: . lºc §§ º: ºğ. - § GREENYAVIC]º [. MERIDIAN ZENITH DISTANCES of ). DRACONIs witH THE REFLEx ZENITH TUBE, 1886 TO 1899. APPENDIX TO GREEN WICH OBSERVATIONS 1904. = Nº Miſſºl!'); 'º Nº!!! TITTF -N Yºniº ſºº - - : =}|E|IIIſºlº || ſºlº IIHIIIIHE -- AARTÉ's AW (SCIENTiºjº º: OTT º | LIBRARYºº RSITYOF ^of THE || MICHIC s Tººntº'ſ #ºn ; &R’s - . : E E E E E E E E \ # :f H f # # Tºll | l º % Z. }: # ſ#| ſ ** H . IIITIIITITIIIHIIIHITIſ: Ú .. º Astronomica; Observatory Q. B 6 \ . G. 342. MERIDIAN ZENITH DISTANCES () F Y DRACONIS * FROM OBSERVATION'S MADE AT THE ROYAL OBSERVATORY, GREEN WICH, WITH THE ERE FILE X Z E NIT H TU BE DURING THE YEARS 1886 TO | 899 : UNDER THE DIRECTION OF SIR WILLIAM HENRY MAHONEY CHRISTIE, K.C.B., M.A., F.R.S., ASTRONOMER-ROYAL. (FORMING AN APPENDIX TO THE VOLUME OF GREENWICH OBSERVATIONS FOR THE YEAR 1904) e ºf e © & & ' º E D IN B U R G H : PR IN T E D F O R H IS M A J E S TY'S ST. A TI O N E R Y O F FIC E * By NEILL & CO., LIMITED, BELLEVUE. tº-ººmºº 1906. {A} & A ...? & - & A- p ...: 'y ſº - f * ,- &/ºw h Zºº. &#,A#2 } g ** t * &ern t/ e. Zººtº eſ * P. , f r /. { 4. Álvº. *.*.*...* r Aft. +--a wº cº- * ... * } / f ! --- tºº § IN T R O DU CTION. THE reflex zenith tube was erected at the Royal Observatory, Greenwich, in 1854, and a full description of it is given in Appendix I. to the Greenwich Observations for that year. The instrument was designed by Sir George Airy for the observation of zenith distances of stars which pass very near the zenith, especially of y Draconis, with the object of determining the constant of aberration, and also the parallax of the star. Discussions of the observations by Mr. Main (Memoirs, R.A.S. Vol. XXIX.) and by Dr. Downing (Monthly Notices, R.A.S. Vol. XLII.) gave in both cases a negative parallax and a value of the constant of aberration which was inconsistent with other determina- tions. These anomalous results were regarded as evidence of undiscovered instrumental error, and it was suspected that the annual variation of temperature might affect the observations by alteration of the scale value. An investigation of the scale value at different temperatures was accordingly made in the years 1883 to 1885, by transits of y Draconis, with the result that no explanation of the anomalous results could be found. The regular observations of y Draconis were resumed in 1886 and continued to 1899, when observations were discontinued. In 1902 Dr. Chandler showed (Astronomical Journal, No. 511) that the anomalous results were entirely accounted for by variation. of latitude. The observations from 1886 to 1889 are accordingly printed in this Appendix, with a very brief account of the investigations of scale value at different. temperatures made in 1883–1885. An examination of the possible effect of temperature was prompted by the following considerations. The temperature at the time of observation reaches its maximum and minimum respectively at nearly the same time as the parallax. The zenith distance (north) of the star would, due to parallax alone, be greatest in June and least in December. This zenith distance is measured by the interval between two wires, mounted in a gun- metal frame, and if the angular value of this interval varies with the temperature through the difference of expansion of gun metal and the object-glass, a spurious parallactic effect will be produced. For more accurate determination of the focus a prismatic focussing rod with scale reading (by vernier) to gºoth of an inch (representing Tºoth of an inch in the focal iv. MERIDIAN ZENITH DISTANCES OF y DRACONIs. length) and ivory point for contact with the mercury, was applied to the instrument in 1882, April, in place of the former light brass rod and wooden float. The focussing rod and the micrometer frame are both of gun metal. A system of thirty wires was inserted in the micrometer frame, and values of the scale corresponding to different temperatures and to different readings of the focal length were determined by means of transits of y Draconis across the wires, the wire frame being rotated through 90° for this purpose. The reading for focus was noted at each transit, and a thermometer, placed close to the instrument, was read before and after the observations. The intervals of the wires were also measured in terms of each of the micrometer screws A and B by means of cross-wires in a four-glass eye-piece, which was mounted so that it could be brought opposite to each wire in succession. The interval between this wire and an adjacent one was then accurately measured in terms of the micrometer screw. Thus the relative intervals of the wires were found and referred to the mean interval. The following table gives the deduced value of the mean wire interval on each day of observation, along with the corresponding temperature and reading for focus. A few observations of 9 Aurigae, made in 1885, February, are included. These are made comparable with those of y Draconis by multiplying by the factor 1.0015. As far as practicable, transits were observed over all the thirty wires, and in the case of incomplete transits corrections were applied to reduce to the mean interval for the complete set of wires. In several cases the instrument was re-focussed in the middle of the transit, the second reading given in the table being that to which it was then set. As the wires were renewed in 1883, October, these observations were discussed in two groups. The first group of 44 observations at temperatures extending from 54° to 72° gives a change of +*0023 for 1° of temperature in a mean wire interval of about 21°, while the second group of 69 observations at temperatures from 45° to 71° gives a change of — “0008. The discordance in these two results shows that many more observations would be required to obtain a measure of the actual change of scale due to temperature. The readings for focus were also compared with the temperatures, and the results obtained from the two groups are of opposite signs. INTRODUCTION. V. Mean Intervals of Wires from Transits over thirty wires. º Reading || Reading Date. Observer. Temperature. F * g 1:... Date. Observer. Temperature. F *. tººl 1883 O l]]. S . 1883. O in. S May 15 L 59 O e º 'º 2O. 947 | Sept. 19 T 66 - O o: 28 || 2 I O4o I6 HC 63' o o' 42 2 I o62 26 H 63 - I O 32 || 2 I O45 17 H 59 o O' 41 || 2 I of 2 2 I H 59.8 O' 4o 2 I OoA Oct. I H 54." O o' 34 || 2 I of 8 2 2. AD 59'8 ::::) 2O ‘979 I 8 H 55 ° 2 o' 29 || 2 I o25 2 3 L 65 o o' 30 || 2 I o67 Mean..... 63 - 6 O 32 || 2 I O3 I 25 H 62. 9 O' 42 || 2 I O44 3 I L 57 - 2 o' 34 || 2 I O23 June I T 6 I o o' 37 || 2 I og I f e te .26 4. H 6o o o' 39 2 I og I Nov. 26 H 49' I o' 30 2 I oô4. 8 H 59 - 7 O' 43 || 2 I O J I 1884 9 * º º ...? May 22 L 57° 3 o' 24 || 2 I of 6 | | | | }. ... . . . . 26 || || || 3:6 || 3 || “...º. 29 AD 68. 3 o’ 23 2 I o4.o 27 L 58. I o' 28 || 2 I 119 3O T 68 - O 9° 23 | ** '957 |June Io H 56-o o' 39 || 2 I og 2 t I I JP 60 - 2 o' 38 || 2 I of 4 July 4 T 67 o o: 23 2 I OS2 I 2 L 62 - 4. O' 38 || 2 I of 3 6 JP 66. I o' 3o 2 I or I I6 JP 59 - O o' 39 || 2 I oz.9 9 HC 66 - 8 o. 28 2 I ooé 2 3 H 65 o o' 385 2 I O24. I I SD 64' 9 o 28 2 I or 6 3o L 68 - 2 o' 38 || 2 I of 6 17 H 59'8 o' 29 || 2 I O47 * 26 HC 62 - O o: 29 21 o28 |July 1 H 68: 5 o' 38 21 o24 28 L 65.6 O' 30 2 I O25 & o- 38 g 3O H 64 - O o' 37 || 2 I o42 2. AD 69' 9 J. ::, 21 of 8 4. L 73° 9 o' 38 21 o27 Aug. 3 H 65 - 1 o. 38 21 o61 7 H 68 - O o' 38 || 2 I on 9 9 T 6I - O o' 38 21 o28 9 T 72 3 o' 38 21 oz 3 I I BB 64-7 o' 30 2 I O34 * * ſo. 38 o I 3 T 69' o O 32 2 I o29 I 2 AD 67 - 2 to-1, *05 I4. HC 68 - 2 o' 30 || 2 I o26 o' 37 º I6 H 63 - 1 o' 38 || 2 I o28 I6 L 64-4 o. 27 | ** oz8 I 8 BB 67 - 3 O' 3o 2 I o42 17 H 64-6 o' 38 21 og 3 2. I # §: o' 3 I 2 I O45 I9 T 62-7 ...; 2 I og.9 2 3 9° o: 29 21 o27 * > o' 3 g 24 HC 69 9. o' 27 2 I oz 3 25 AD 62 - 9 ſ: 2 I ooô 25 SD 67. 5 o' 25 2 I Os3 {º o. 38 e 28 H 69. I o' 39 || 2 I of 9 3 I L 72.7 o., | ****7 Sept. 8 AD 59° 2 o' 27 2 I o41 o & o' 38 º I 2 L 61 - 2 o' 29 2 I o24. Aug. |H 70 ° 3 o. 35 | ** o26 I 3 AD 62 - 8 o: 28 2 I o27 e ſo. 54 © 18 HC 66 o o' 29 2 I oso 6 H 69' o io. # | ** o:6 1883 June 9. Focussed at wires 1–4. 1884 July 9. Focus fairly good. July 31. Focus very little better after alteration. Aug. 2. A piece was cut off ivory point of scale, shortening it by '1 12 inches or 224 in scale-reading. vi MERIDIAN ZENITH DISTANCES OF y DRACONIs. Mean Intervals of Wires from Transits over thirty wires—continued. Reading Mean Reading Mean Date. Observer. Temperature, r: Interval. Date. Observer. Temperature. for Interval. OCU.S. Focus. 1884. o in. S 1885. © in. | S Sept. I AP 63-8 o. 38 20. 983 e ſo. 5 I • *\ ºf A-7 4. T 6I • I O' 37 || 2 I O40 July 1o AD 67. 9 lo'44 2 I O47 17 HT 74-6 |: 2 I on 7 I I T 69' o ſº 2 I o64 ſo. 51 I4. H 64. 9 lo. 54 2 I og 2 I 8 AD 72 - 2 lo'42 2 I • O28 17 L 63' 9 O' 52 2 I og 3 25 JP 60 - O O 5 I 2 I O42 20 AD 67 - 3 |...} 2 I O43 | Nov. 3 HT 52.8 o' 51 20. 976 2 2. T 65° 4 o' 56 2 I O40 25 JP 71 - 3 o' 51 2 I O65 Aug. 8 H 65 - O O 5 I 2 I O43 1885. I O L 65. 2 O' 52 2 I O4. I Feb. 6 H 45 ° 9 o' 51 || 2 I o68 I 4. L 6I 2 O 54 || 2 I O29 I 5 T 63-6 o' 51 2 I oš6 May 8 HT 46' 2 o' 51 || 2 I of 8 2 O H 60 - O o. 51 21 o66 23 H 51 - 7 O' 51 2 I O42 2 2. L 61 - 4. o' 48 2 I o61 27 H 60 4 O 5 I 2 I O49 º ſo. 5 I º 29 L 59 7 || O' 52 || 2 I of 4. 24 H 62.5 ||...}, 21:939 June 4 || RW 67.8 O 5 I 2 I O25 | Sept. 3 AP 63 - 2 O 5 I 2 I O55 e o' 48 e 4. RW 62 - 3 o 5 I 2 I o6 I IO L 59' I |...; 2 I of I 5 R 63' o O' 5 I 2 I O 54 g O' 54. e º ſo 5 I º I I AD 57.8 {:}; 2 I O35 I I AD 57 ° 4 lo. 48 2 I oz.9 I 2 AP 61 - 9 O 5 I 2 I of 3 2 I L 61 - O o. 5 I 2 I O22 I 3 T 63-8 o 5 I 2 I of 7 2 2. RW 6o 8 o' 48 || 2 I O4. I 17 RW 58' 5 o' 51 || 2 I oz.6 I 8 H 60. 9 ſº 2 I O34. 62 - 8 2 I of 7 2 - o' 5 I º 2 O AD 58-7 |...}. 2 I O48 9 AURIGE. ſo. 51 o 1885. 26 H 57' 5 {...}. *942 Feb. 7 H 48.7 o' 5 I 2 I oš9 27 L 6o. 5 o' 5 I 2 I or 9 I 8 L 48° 5 o' 55 || 2 I O4·o º ſo. 51 e Zºº ºf 19 T 4.3 ° 2 O' 55 2 I O25 3O H 60 - 5 to.19 |**5. 2. I L 42 6 o' 57 || 2 I of 7 25 L 56' 5 o' 54 || 2 I O24. July 6 AD 69' o o: 51 || 2 I o26 27 T 49° 7 o' 51 || 2 I Oo3 8 H 64' I o' 5 I 2 I of 6 9 L 65 " I o' 49 || 2 I of 8 48 - 2 2 I of I 1884 Sept. 18. Focus bad at to 51. Sept. 25. Focus good. Nov. 3. Focus fair, 1885 June Io. Image bad ; not improved by focussing. June 17, 20, Aug. 8, 14, Sept. 4. Focus good. June 27, July 17, Sept. 21. Focus fair. July 20. In good focus at 'o';1. July 25. In good focus. Aug. Io. Fair image. Aug. 24. Focus not good at 'o';1. Sept. 5. Very faint at times; cloudy. INTRODUCTION. vii Taking the coefficient of expansion for brass as 000018, a variation of +0°00038 per 1° Fahrenheit would be expected in an interval of 21°. With a range of 20° in the temperature between summer and winter, this variation would imply an effect on the parallax of 0"-036, whereas the observations discussed by Mr. Main and Dr. Downing showed that the quantity in question was 0"-20. It was concluded therefore that the spurious parallax was not attributable to temperature. As stated above, the anomalous results were accounted for by Dr. Chandler by the variation of latitude which had not been discovered when these discussions were undertaken. The observations of zenith distance of y Draconis 1886–1899 were made as in previous years, and the results are given in substantially the same form as in the Greenwich Observations up to 1881. s The correction due to the readings of the level-scale is determined from the following considerations:—When micrometer A is to the left—that is, south of the zenith—the micrometer readings increase as the wire moves to the left—-that is, as the star's zenith distance north increases; and, in this position, the readings of the level-scale increase from left to right, and therefore the level-indications will increase when the right or northern edge of the object-glass is raised. Supposing this northern edge to be raised, the central ray of light for a Zenithal star, descending through the focal centre and reflected up through the focal centre, meets the wire-frame (which is above the focal centre) not at its zenithal point, but at a point which is north or to the right of the zenithal point. Therefore the wire, when in that position it is laid upon the star, is more to the north or right than it ought to be ; and therefore its micrometer-reading is smaller than it ought to be, and a positive correction is required: that is, for increasing readings of the level-scale the correction is positive. The linear amount of the correction (omitting a constant depending on the zero of the level-scale) is {dist. from focal centre to wire-frame} × {} sum of readings of level-scale; x {value of one division of level-scale). The angular amount of the correction is this quantity divided by the focal length of the object-glass. viii MERIDIAN ZENITH DISTANCEs of y DRACONIs. From statements made by the late Mr. William Simms, it is assumed that the focal centre coincides sensibly with the upper surface of the object-glass, and therefore that the distance of the plane of the wires from the focal centre = 0"25; and that the value of one division of the level-scale is 6" nearly. Also, the focal length of the object-glass, which is that of Troughton's transit instrument dismounted in the year 1851, is 116 inches. With these data, the correction to zenith distance due to the readings of the level- scale is found to be 0"-00646 x sum of readings of the level-scale. From these numbers, the numerical value of the sums of equivalents for micro- meter-readings and for level-readings is computed by the formula given in the foot- notes to the Observations; and thus is obtained the zenithal distance of the star, as measured towards micrometer B, increased by an instrumental constant, which it is necessary to determine from the observations. This constant is usually determined by forming for each day the half-sum of the two sums of equivalents in the two reversed positions of the instrument, and by taking the arithmetical mean of those half-sums determined on different days. By subtracting this constant from the sum of equivalents when A is to the left, or by subtracting the sum of equivalents from this constant when A is to the right, the star's observed zenith distance north is obtained; and by applying to the mean of the two results L and R, the correction for the reduction of apparent Z.D. to mean Z.D. north, the mean zenith distances north given in the last column of the tabular arrangement are found. - f - W. H. M. CHRISTIE, Royal OBSERVATORY, GREENWICH, - , - 1906 February 27. . ROYAL OBSERVATORY, GREENWICH. MERIDIAN ZENITH DISTANCES OF 7: DRACONIS THE REFLEX ZENITH TUBE 18 S 6 T 0 || 8 99. GREENWICH OBSERVATIONS, 1904.—APPENDIX I. - {B} OBSERVERS WITH THE REFLEX ZENITH TUBE IN THE YEARS 1883–99. Observer. Mr H. H. Turner Mr A. M. W. Downing Mr W. G. Thackeray. Mr T. Lewis Mr H. P. Hollis. Mr A. C. D. Crommelin Mr W. W. Bryant Mr T. C. Hudson Mr J. W. H. Pead Mr J. Power Mr J. A. J. Pead Mr B. Bennett . Mr W. H. Cox . Mr S. Dolman Mr R. Woodgate Mr F. C. Robinson Initials. HT AD T L H AC B TH HP JP AP BB HC SD RW R Observer. Mr T. F. Fisher. Mr H. A. Wise . Mr W. Russell . Mr A. Cochrane. Mr A. P. Miskin Mr H. H. Furner Mr C. R. Davidson Mr C. Martin Mr D. J. R. Edney Mr W. Bowyer . Mr R. W. Cheeseman. Mr G. F. Johns. Mr E. H. Banks. Mr P. G. ShoWell - Mr W. M. Witchell . © Mr J. Storey Initials. F AW WR A C* AM HF CD CM DE WB RC J EB S W JS The letters L and R in column 4 denote respectively that micrometer A was to the Left or to the Right. MERIDIAN ZENITH DISTANCES OF y DRAGONIS WITH THE REFLEx ZENITH TUBE, AT THE ROYAL OBSERVATORY, GREENWICH, 1886–1899. 3 - MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEX ZENITH TUBE. # - Micrometer Readings. Level Readings. Sum of Equiva- Concluded º Day and Hour º --> lents for wire, Star’s Mean ‘s of ... . . . ; 5, , for Micrometer- observed Star Zenith p3 Observation, g 5 É A. B. r: g: Readings and Zenith Distance | Correction. Distance . 3 I886. § # g div. div. º º for Level- North. North Ž à || 3: : 7". 7". ă3 Readings. I886°o. - h f / f A f f 4 / 4 / & ºf I June I. I 3 || L | L | 16 || 27'Ooo 47.245 9°2 66-6 o'49 7. 16.63 I. 35’ I 5 – 3' 17 | I. 32'24. R I 5 27:362 47°245 25'4. 82°5 o'70 4. 5'8 I I. 35-67 º 2. 4. I 3 | H | L | 16 27°ooo 47°390 I I "O 68-8 o' 52 7. I 9'09 1. 37-61 — 4.' I 6 I, 22 ° 2 O R I 5 27'253 47'390 23'O 81°o o'67 4, 6'38 I. 35' Io 4. . 32 3 7. 12 |AD | R | 15 27°536 || 47°ooo 27.4 | 84.9 o'72 || 4. 4.63 ! 3: – 5:15 | 1.31-60 L | 16 27°536 || 46.799 9'5 67°o o°49 7. 18:13 1. 36.65 4. Io. 12 | T | R I 5 27-209 47'O35 23.8 81.4 o'68 7. 16.81 I. 35' 33 – 6: I I, 2 O' H L | 16 || 27-209 47' 218 Io'3 67.7 o'50 4. 2'59 I. 38.89 4. . 3o'97 5 12. I2 | H | L | 16 28-ooo 46:342 8:8 66°o o'49 7. 18:25 1. 36-77 – 6-78 1. 3 1:40 R I 5 28'03 I 46'342 26-6 84°o o'71 4. I '89 I. 39'59 7 - 3 I '4 6 I 5. I2 AD R | 15 28-073 46:350 26-3 84'o o'71 4. 2 73 I. 38.75 – "7" I, 2 O' L | 16 || 28'073 46.353 8-O 67°o o'49 7. 19:67 1. 38' 19 7'74. . 3O'73 7 28. 12 || AD | R | 16 || 22 oz.8 4O'2 oo 27.7 83.5 o'72 3. 55°22 I. 46 26 - I I "OO I. 2 2-6 L | 17 22 oz8 4 I 253 9°o 65°o o'48 7. 26:36 I. 44-88 9 . 33-07 8 3o. 1 1 | T | L | 16 || 27:600 46'996 6-6 || 62'3 o'45 7. 22'48 I. 4 I too – I 2'54 I 3o4. R | 15 27.058 46'996 || 31.5 | 86.7 o'76 3.56-59 I. 44'89 © 9 July 1. II | L R 15 26'947 47"Ooo 86-6 3o’8 o'76 3. 54*79 I. 46-69 — 1 2-84 1. 32°20 L | 16 || 26'947 47 '79 I 6'5 62°4 o'45 7. 24.86 I. 43°38 I O 2. I I AD | L | 16 27°ooo 47-833 7:o 63'o o'45 7. 26:45 I. 44'97 – I 3 'I 4 I. 3 I '74. R | I 5 || 26'229 || 47°833 29'5 | 85.3 o'74 3. 56'70 I. 4478 I I 3. I I | H | R | I 5 26°og7 48'Ooo 3O'3 84'4 o'74 3. 56-28 I. 45’2 O – I 3 '44. I. 3 I-69 L | 16 || 26-oa 7 48.8oo 8-5 | 62-5 o'46 7. 26.53 I. 45 ‘O 5 e I 2 5. II | T | R I 5 25' 139 || 48-829 35.8 89.4 o°81 3. 55' IQ I. 46.29 – I4'O4. I. 3 I '85 L | 16 || 25°139 || 49'725 3° 3 || 57'2 O'4. I 7. 26.96 I. 45°48 I 3 6. I 1 | AD L | 16 || 25°ooo 49'87 I 6'o 59°5 O'42 7. 27-07 I. 45° 59 – I 4'34. I. 3 I '83 R I 5 24'072 49'87 I 32°9 86.2 o'77 3. 54'73 I. 46.75 I4. Io. II | T | R | 15 24'081 49'90o 32-8 89.3 o'79 3. 55°39 I. 46-09 – I T * . - L | 16 || 24'o81 50'905 2'3 60-7 o°41 7. 28'98 I. 47' 5o I 5'54 I. 3 I-26 I 5 12. Io H | L | 16 24'ooo 5 I ‘O2O 5' 5 62-8 || O'44 7. 29'59 I. 48*I I — 16: Io I. 3 I 58 R I 5 22.895 5 I ozo 297 86°4 o'75 3. 54'24. I. 47'24. - 3 I 5 I6 15. Io L | R. I 5 5O'O4. I 23.8oo 3 I 3 88.2 o'77 3. 53'O2 I. 48°46 – I fºr " g L | 16 || 5o'o.41 25'Ooo 4' 5 61.8 o'43 7. 29'93 I. 48°45 I6'94 I. 3 I ‘52 17 16. Io | H | L | 16 || 5 o'ooo 25°167 8°o 63-6 o°46 7. 32.08 I. 50-60 — 17°22 I. 33°O 5 R 15 48.588 25' 167 297 85°o o'74 3. 5 I 55 I. 49'93 18 August 2. 9 | H | L | 16 49'OOO 26-312 9°o 65.8 o'48 7. 34°52 I. 53'O4 – 21 50 I. 31-67 R | I 5 || 47°244 26-312 26' 5 83’5 o'71 3.48° 18 I. 53° 30 º The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 6or) x 16" 78o + sum of Level-Readings x o”“oo646; where the Wire Interval for wire 15 is zero, for wire 16 = + 3’. 17”. 1 1, and for wire 17 = + 6'. go”82. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1886 the adopted Instrumental Constant was 5'.41"'48. 2. The reading of micrometer B has been increased I rev. 4. The reading of micrometer A has been diminished I rev. 5. Cloudy. 6. The reading of micrometer B has been diminished 1 rev. 9. The reading of micrometer B, position R, has been diminished I rev. 13. The reading of micrometer B was set down 50°129. It has been assumed, however, that the micrometer-head was read in the wrong direction. 18. Diffused and tremulous. * MERIDIAN ZENITH DISTANCEs of y DRACONIs witH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. Concluded # Micrometer Readings. Level Readings. Sum of Equiva- : Day and Hour * --> lents for wire, Star’s Mean º of :- gº ". ; , ; for Micrometer- observed Star Zenith pº Observation, g 5 É A. B. º: £ Readings and Zenith Distance Correction. | Distance 3 1886. § | 3 || s div. div, 3.3 for Level- North. North c .# 3 : 7". 7" § 5 Readings. 1886°o. 2. O Pi— © 5: ‘Sº d h Af f */ f A M & 4 & 4 & I August 6. 9 | H | L | 16 || 47.1 oo 28-258 8'2 64'o o'47 7.35°28 1. 53.8o — 22° 28 I, 2 I* I R I 5 || 45'298 28-258 28°2 83.8 o'72 3.48°19 I. 53°29 3 . 3 I*I'ſ . 2. Io. 8 | H | L | 16 || 45'300 || 3 o'I3 I I 1.2 | 67.3 o'51 7. 36'55 I. 55°o7 tº * R I 5 43'328 3O' I 3 I 24'9 8 I'o o'68 3. 46-52 I. 54-96 — 23°22 I. 3 I-80 3 14. 8 | H | L | 16 || 43°200 32°240 || 1 || 6 | 68.8 o'52 7. 36.71 I. 55 '23 = *) º º * R I 5 || 4 I ‘225 32'24.O 25°o 81.5 o'69 3. 46.63 I. 54'85 23°94 I. 3 I Io 4. 3o. 7 | H | L | 16 || 45°ooo 30-638 I 5' 5 69.6 O'55 7.4o'o6 1.58:58 — 26-22 I. 3 I ‘Al2 R I 5 || 42.720 30-638 23'2 77°o o'65 3. 44'79 I. 56-69 . 3 I ‘4. 5 31. 7 | T | R | I 5 || 42-650 || 30-640 I ‘5 || 74’3 o°62 3.43°63 I. 57'85 = 2. f.) * º - L | 16 || 42-650 32-94.1 5'8 | 68.3 o'54 7. 39'27 I. 57'79 26-30 | I. 31'52 - 6 September 1, 7 || AD | L | 16 || 42°65o 32°974 I5'9 69°o o'55 7. 39'84 I. 58°36 –26-28 I. 3 I*30 R | 15 40°367 32°974 22-2 || 75-6 o'63 3.44:49 I. 56'99 38 I. 7 3. 7 | H | L | 16 || 41 ooo 34-602 I6'o 71°8 o'57 7. 39'48 I. 58°oo smass 2 ſº * g R 15 38-656 34-602 2 O' I 757 o°62 3. 43'09 I, 58.39 26'54 I. 3 I-66 8 6. 7 || L | R 15 38.732 34-600 2O" 2 76.2 o°62 3. 44'32 I. 57 16 – 2 ºn * . L | 16 || 387.32 36'978 I6'8 72°2 o'58 7. 4 I 3 I I. 59'83 2678 I. 3 I'72 9 7. 7 | H | L | 16 || 39-ooo 36'642 I 6-6 72. o:57 7. 4o’ I 5 1. 58-67 = 2 ſº * ſº R 15 || 36-602 || 36.642 20-6 76°o o'62 3, 42.86 1.58-62 2686 | 1.3179 IO 8. 7 | R R 15 36-327 37°ooo 2O'8 76.6 o'63 3. 44-26 I. 57°22 º ~~~~ L | 16 || 36-327 39'3 II I5'9 71.6 o'56 7. 4o'o'7 I. 58'59 –26'94 I. 3O'97 I I 13. 7 || AD R I 5 || 33°619 39'650 19:6 75.3 o°61 3. 43'27 I. 58.2 I sms 2 ºf * tº L | 16 || 33°619 || 42'o66 14:9 || 71.4 o'56 7.40-86 I. 59°38 27°14 I. 3 I-66 I 2 I4. 6 JP L | 16 || 33-62o 42’ I 52 I6' I 72°3 o'57 7. 42°34 2. o'86 – 27 I 8 I. 32-61 R 15 31'087 42’ I 52 197 75-7 o°61 3.42.76 I. 58-72 7 ... 3 I 3 16. 6 L | L | 16 || 33-ooo 42 7 I 5 II 4 || 70°8 o'53 7. 4. I'34. I. 59'86 tº * > R I 5 || 30-536 42 7 I 5 23'3 8o'4 o'67 3.43°O3 I. 58:45 – 27.26 I. 3 I-90 I4. 17. 6 || AD R I 5 || 30-545 42'700 26°o 837 o'70 3. 42'95 I. 58°53 * gº L | 16 || 30°545 45°o97 8-8 66-2 O'49 7.40-24 1.5876 – 27°30 I. 3 I 35 I 5 2.2. 6 JP L | 16 28:20o 47.351 5.8 63'2 o'45 7. 38' 5 I I. 57'O3 – 27-26 ~~ R I5 25'938 47'351 29.8 87.5 o'76 || 3. 43-75 I. 5773 27:20 I. 30. I2 The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 6or) x 16" 780 + sum of Level-Readings × o”oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3’. 17”. 11. 9 The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1886 the adopted Instrumental Constant was 5'.41”:48. 5. Very diffused. The reading of micrometer B, position R, was set down 34-64o. 8. Diffused and tremulous. 15. W ery cloudy. The reading of micrometer A, position 6. Wery tremulous, L, has been diminished I rev. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886–1899. MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEX ZENITH TUBE-continued. § Micrometer Readings. Level Readings. Sum of Equiva- Concluded # Day and Hour tº --> lents for wire, Star's - Mean à of H . . Tº - § - for Micrometer- observed Star Zenith as & Observation, g 3 || 3 A. B. is § | Readings and Zenith Distance Correction. Distance 3 § | 3 || 3: div. div. 3.3 for Level- North. North Ž - É É : 7". 7". ă 3 Readings. 1887“o. d h 4 / & 4./ & 4 / f f & ºf f I June Io. 12 JP L | 16 || 30-500 43-684 17.8 74°4 O'60 4. 27°92 I. 33.85 — 4'60 I • 2 Q"'7 O R I 5 || 31°oo8 43-684 18'5 75' I o'60 I. I9'33 I. 34'74. 4. . 29.7 2. 11. 12 F | L | 16 || 30-800 43’508 || 16.5 | 72°o o'57 4, 29.96 I. 35'89 - 4."O2 | I. 3 I "S 2 R I 5 || 3 I oA.8 43’508 I 8°8 79°o o'63 1. 17:08 1. 36'99 \ 4'9 . 3 I'5 3 13. 12 |RW L | 16 || 31 ooo 43'479 I6'6 71°8 o' 57 4, 32-84 1. 38.77 — K. 56 I. 22 °2 I R I 5 31'o60 43'479 74°5 20°o o°61 I. 17'I I 1. 36.96 5°5 . 32°3 4. 14. 12 F | L | 16 || 31°ooo 43°391 || 17-3 || 72°o or 58 4. 3 I ‘37 1. 37:30 — 5'88 I. 32°o7 R I 5 || 3 I'o'70 43°39 I I9'o 75°o o'61 I. I 5'47 1. 38'60 & 5 ... I 5. I2 || AD | R I 5 || 3 I Io; 43'4Oo 19:6 74-6 o’61 I. 16:20 1. 37.87 mes ſh" tº L | 16 || 31°105 || 43°297 15-6 || 71°3 o'56 || 4, 31-53 I. 37°46 6’20 | I. 31'47 6 16. 12 L | L | 16 || 31°ooo 43°496 15-8 || 70.6 o'56 4, 33° II I. 39°o4. – 6: R2 I, 2 I ‘2 R I 5 || 3 I’og2 43'496 2 o'8 762 o'63 1. 17-61 I. 36.46 || 5 - . 3 I ‘23 7 17. I 2 | H | R I 5 || 3 o'5o I 44°ooo 22 "O 777 o-65 I. 16' 18 I. 37.89 — 6-8 I. 3 o'48 L | 16 || 30-501 43°859 I4'8 7o'2 o°55 4. 3O'82 I. 36.75 4. • 30°4 8 20. 12 || AD R I 5 3o 106 44'4Oo 23°o 79.6 o'66 1. 16.27 1. 37.8o sºme ºf * tº L | 16 || 3 o' loé 44'347 I I-6 68-6 o-52 4- 32°35 1. 38'28 7.8o I. 3 o'24. | tº e : , º 9 3o. II | H | R 15 29.261 45°ooo 25°2 81.8 o'69 I. I 2 °2O 1. 41.87 am iſ ſº * * , L | 16 29.261 45' 393 2O"O 66.8 o'50 4. 35'7 I I. 41'64 Io'90 1. 30-86 Io July 2. I I AD L | 16 29:300 45°328 I O'O 65°o o'49 4. 35.26 I. 4 I IQ amme * ſº R | I 5 28'946 45°328 26'8 717 o:64 I. I.2°37 I. 4 I '7C I I'52 I. 29'93 I I 3. I I | T | R | 15 28:920 45 °35'O 27' 5 8o-6 o'70 I. I.2°39 1. 41.68 ams * © L | 16 || 28'920 45'82O I O'2 63-8 o'48 4. 37' I 3 I. 43'o6 11.83 | 1. 39'54 I 2 II. I I | HT | R I 5 || 31-326 42:700 3o' 5 84'2 o'74 I. 8:30 I. 45'77 = . A * Q L | 16 || 31°326 42'33O 8'2 62.8 o°46 4. 35'70 I. 41'63 14:28 I. 29°42 I 3 18. Io L L | 16 || 29°ooo 46-046 7.9 || 64.2 o'47 4. 42°25 I. 48.18 * I ºn " tº R | 15 27.892 46°oA6 28.6 85°o o'74 I. 6-8 I I. 47.26 I6'24 I. 31'48 I4. 20. Io AD | R | 15 27: 542 46'40o 28:8 84°o o'73 1. 6'87 I. 47°2O sms I fºl" e L | 16 || 27: 542 || 47-335 8-6 64°o o'47 4. 39'42 I. 45°35 I6'8o I. 29 * I 5 27. Io T | R I 5 3 I '835 42 "Ooo 3 I'o 85.3 o'75 I. 5°og I. 48.98 - 1 × " & L | 16 || 31 835 | 43°354 || 7-9 || 62-8 o'46 || 4.44:64 I. 5 o'57 18°55 I. 3 I-23 I6 28. Io AD | L | 16 || 3 || 8oo 43°427 8:3 637 o'47 4. 4.5°30 I. 5 I ‘23 —1880 I. 2 I* I R I 5 3O'427 43'427 29' I 84-6 o'73 I. 5'40 1. 48-67 . 3 I’ I 5 17 31. 9 | T | R I 5 || 30-878 43°ooo 29'2 84-6 o'74 I. 5'8 I 1. 48-26 – I ſh" © L | 16 || 30-878 || 44.289 7-8 63-1 || 0:46 4. 44:28 I. 5 o'2 I I9'5 I I. 29.73 I 8 || August 3. 9 || L || R. I5 29'650 44'OOO 297 85.8 o'75 I. 2 "OO I. 52'o'7 * e L | 16 || 29'650 || 45-466 6-6 || 62:4. o'45 4. 43'4. I I. 49°34. – 20° 14 I. 30°57 The numerical value of the Sum of Equivalents in column 11 = Wire Interval +...(sum of Micrometer-Readings – 7or) x 16" 780 + sum of Level-Readings x o'''ooô46 ; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3'.17”. 11. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1887 the adopted Instrumental Constant was 2.54”'oZ. 1, 7, 13. Diffused. 2, 4, 17. Very diffused. 11. The reading of micrometer A was set down 31*020. 15, 18. Very diffused and tremulous. 2. The reading of micrometer A, position L, has been diminished 1 rev. 5. The readings of micrometer B have been diminished each I rev. 12. The reading of micrometer B, position L, has been diminished 1 rev. " 16. Faint ; cloudy. 6, 14. Very tremulous, MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEX ZENITH TUBE, MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEX ZENITH TUBE-continued. # Micrometer Readings. Level Readings. Sum of Equiva- Concluded : Day and Hour * ... --> lents for wire, Star’s Mean *::: of :- . . . ; : for Micrometer- observed Star Zenith & Observation, g 5 É A. B. + £ Readings and Zenith Distance Correction. Distance 3 1887. ; # g div. div. º º for Level- North. North % à | < : 7". 7". 33 Readings. 1887'o. d h 6 6 6 6 44 4 A w 4 4 / 4 / 4 A f I August 4. 9 || T | L | 16 29'65o 45'554 ‘5 27 | O'45 4. 44'89 I. 50.82 - ? (Y" , a. as e +. R I 5 27.988 45'554 3 I I 86.2 o'76 I. o' 19 1. 53-88 2O'35 I. 32°oo 2. 5. 9 || AP R | 15 28°482 45-556 307 | 85.6 o°75 I. 8:50 I. 45" 57 – 2 Ch" & L | 16 28°482 46-600 7'o 61-8 o'45 4. 42'83 1. 4876 so 56 (1.26-61) 3 22. 8 || L || R. I 5 3o'58o 43°ooo 32’6 89'o o'79 I. o'86 I. 53'2 I 'a-, *, *, * g L | 16 || 30-580 || 44:816 3-8 60-6 o'42 4.48°O7 I. 54°oo 23°49 I. 3 o' I 2 The numerical value of the Sum of Equivalents in column I I = Wire Interval + (sum of Micrometer-Readings – 7or) x 16" 780 + sum of Level-Readings x o”ooô46; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3'.17". II. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1887 the adopted Instrumental Constant was 2.54" oz. 1. The reading of micrometer A was set down 31°988. 2. Very diffused. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886–1899. MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. # Micrometer Readings. Level Readings. Sum of Equiva- Concluded § Day and Hour º --> lents for wire, Star’s - Mean ‘5 of H e Tº | 5.3 for Micrometer- observed Star Zenith fº Observation, § s É A. B. + £ Readings and Zenith Distance | Correction. Distance & 1888. ; # g div. div. #5 for Level- North. . North Ž à | # | : 7". ')". āş Readings. 1888°o. - d h A ſº f 4 * , º 44 f / f */ I May 12. I4 | T | L | 16 || 34:200 39'444 3 8o.6 o'66 4. I 892 I. 22.8 I 6 - o I. 20:46 R | 15 35'929 39'444 70-6 o'53 I. 30.69 I. 23'42 + 6'35 9'4 2. 22. 14 | H | R I 5 || 33-088 42'ooo 13°o 71°8 o'55 I. 25'92 I. 28.19 • , a tº © L | 16 || 33-088 40°652 20:4 || 78.8 o-64 4. 2 o’5 I I. 26:40 + 3°4 I I. 3 o'71 3 23. I4 || L | L | 16 || 3 o' 5oo 43.395 I 8:8 77°4 o'62 4. 23°o8 I. 28'97 o s R I 5 || 31.842 43°395 14'o | 72-6 o'56 I. 28'44 1. 25-67 + 3’ Io I. 3 o'42 4. 26. 14 | H | R 15 32-161 43°ooo I 5'9 74-8 o'59 1. 27.20 I. 26'91 º e I, 16 || 32° 161 4I '819 I7'4 77'I o-61 4. 24°50 I. 3 o'39 + 2. 17 1. 30.82 5 June II. I 3 | T | R 15 - 32°525 42'20O 20:9 77.3 o'63 I. I 9-92 I. 34” Ig º º - L | 16 || 32°525 || 41'544 || 14-4 || 706 o'55 || 4. 25.94 ; ; ; – 28 i. 3020 6 I4. I2 JP L | 16 || 31-ooo 43' 193 13.8 71. O'55 4. 28'02 I. 33°9 I e I. zo'82 R 15 31'587 43' 193 zo’9 78°5 o'64 I. 20.85 1. 33°26 — 3°77 . 29 7 25. I2 | H | L | 16 || 32-ooo 42'402 I 8-6 73°2 o' 59 4. 31'56 I. 37°45 - *7" - º R 15 32°o28 42'402 17'o 71°8 o'57 I. I.490 I. 39'2 I 7:29 I. 3 I ‘O4. 8 July 19. Io | T | L | 16 - 3 I ‘ooo 43-832 24.8 819 o'69 4. 38'87 I. 44-76 Q º R. I 5 || 3o:265 43'832 Io'3 66. o:50 I. 9:25 I. 44-86 – 14'27 I. 3O'54 9 23. Io | T | R 15 30-295 43-83 I 9°4. 65.6 o:49 I. 97.3 I. 44-38 = ºr " e L | 16 || 30-295 || 44'535 | 26-1 || 82.8 o'76 || 4.38.85 I. 44"74. I 5-27 | I. 29°29 Io August 2. 9 || AD | R 15 29-361 44'6oo 8:3 66-2 o°48 I. 6'95 I. 47' 16 º º L | 16 29-361 || 45-641 25.8 | 84'o o'71 4, 41.75 ; :43, –1761 1, 1979 I I 23. 7 | H | L | 16 || 30-ooo 45.329 22.5 || 797 o'66 4. 4.7’ I 9 I. 53 'o6 e --~ R I 5 28.32 I 45°329 I 2-8 69.8 o°53 1. 1.78 I. 52' 33 –2 I'32 I. 3 I ‘39 I 2 31. 7 | H | L | 16 || 3 o'ooo 45' 309 22 "I 80.2 o'66 4. 46'85 I. 52 '74. - e e R I5 28-306 || 45.309 Io. 5 | 68.3 o'51 1. 1' 17 I. 52 '94. - 22°2 I I. 3c-63 I 3 | September 3. 7 || AP R 15 28-3oz 45' 354. Io'7 67.5 o'51 I. I '86 I. 52'25 º º L | 16 || 28.302 46-978 24' 5 81.4 o'68 4.46°39 I. 52'28 – 22:45 I. 29'82 I4. 6. 7 || AW L | 16 || 28-ooo 47'24.2 26's 832 o'71 4. 45°78 1. 51-67 º e R I 5 26.421 47'24.2 9°o 66.1 o'49 I. I'96 I. 52 'I 5 – 22-69 I. 29'22 I 5 7. 7 | F | R 15 30:856 42700 10:4 68-o o'51 I. O’ I 8 I. 53’93 e º L | 16 || 30-856 || 44'460 25'3 83°o o'70 4. 47°o I I. 52'90 — 22 77 1. 30.65 I6 I I. 6 | H | L | 16 3o-ooo 45°33O 24'6 83°o o'70 4. 47' 24. I. 53° I 3 ~. R I 5 28-2 52 45 °33O Io’9 69'2 of 52 I. or 62 I. 53'49 — 22.89 I. 3O'42 17 | October I. 5 |AW L | 16 || 3o-ooo 45.338 24.5 83.3 o'70 4. 47'37 I. 53°26 º e R 15 28-225 45' 338 8.7 67.9 o°49 I. o. 28 I. 53.83 — 22-69 I. 3 o'86 18 I9. 4 F | R. 15 28-942 45' IOO I6'o 76.3 o'60 I. 8:42 I. 45.69 º e L | 16 || 28-942 46’184 17. I 77.2 o°61 4. 4.3°74. I. 49-63 –2 o'73 (1.26-93) The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 7or) x 16" 780 + sum of Level-Readings × o” ‘oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3'.17”. 11. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1888 the adopted Instrumental Constant was 2'.54” 11. 4. Cloudy ; 2nd bisection very uncertain, the star being only seen at intervals. 7. Wires scarcely visible. 16. The reading of micrometer A, position R, was set down 31r2s2. 17. Faint and diffused. 5. Very diffused. 15. Very cloudy. 18. Scarcely visible. MERIDIAN ZENITH DISTANCES OF y DRAGONIS WITH THE REFLEX ZENITH TUBE, MERIDIAN ZENITH DISTANCES of y DRACONIs observed with the REFLEX ZENITH TUBE–continued, # - Micrometer Readings. Level Readings. Sum of Equiva- Concluded 5 Day and Hour e | --> lents for wire, Star’s Mean ‘5 of . * . . . ; : for Micrometer- observed Star Zenith p: Observation, §: 5 É A. B. º: £ Readings and Zenith Distance Correction. | Distance 3 # | # .# — div, div. £5 for . North. North à à | * B= 7". 7". 33 Readings. n 1889'o. - d h 6 W f * Af f A f £ 4 º f/ I March 22, 18 | T | L | 1 31 ooo 37.865 23'5 86°o o'71 3. 32°33 I. I I'71 º e R I 5 || 34°13o 37.865 87 7o:6 o'51 I. 7' 54 I. I 3 'o6 + 17:47 1. 29.87 2 May 22. 14 | HT | R 15 32°598 38:700 8-0 || 65°o o°47 o. 55'81 I. 24'81 0. e L | 16 || 32°598 37:280 25°3 82.7 o'70 3.49°32 1. 28.70 + 6:36 (1.33:12) 3 30. I 3 || L | L | 16 || 31 ooo 38°587 24.8 82.9 o'70 3. 44'44 I. 23'82 o e R | 15 32678 38°587 92 67.7 o'50 O. 55’29 I. 25°33 + 3-88 I. 28°46 - 4. 3 I. I 3 | H | R I5 29:200 42°ooo 9°o | 668 o'49 o. 54.' I 9 I. 26'43 º I. 2C).” L | 16 29:200 | 40'475 259 || 837 o'71 3. 45°93 I. 25'3 I + 3'57 29°44. 5 || June 4. I 3 | H R 15 31 200 || 4 o'ooo 30°2 66°o o°62 o. 54°32 I. 26°30' e e - L | 16 || 3 1:200 38°642 26'5 82.3 o'70 3.48°7 I I. 28'09 + 2'29 I. 29°49 6 12. I2 | H | R | I 5 27°940 || 43-ooo 9°o 66.5 o'49 o. 49'82 I. 3 o'8o - Ch" e L I6 27'94o 4I'988 26'5 837 o'71 3. So I 7 I. 29'55 o:27 I. 29'91 7 18. 12 ||WR. R. 15 || 30-545 40.266 94 | 66.4 o'49 o. 47.66 : ...?? | – 2:19 i. 29.07 L | 16 || 29'661 40°266 27.2 84'o o'72 3. 50'17 I. 29° 55 o 8 22. 12 | H | R | 15 29'613 4 I'Ooo Io'7 66°o o'50 O. 44' 35 1. 36-27 - 3:45 I. 32'25 L | 16 29'613 40-648 24'6 8o'2 o'68 3. 55°74 I. 35' I 2 4. e 9 25. 12 AD L | 16 29'600 40.738 22°5 78°o o-65 3. 56'98 1. 36:36 * A * º R | I 5 || 3o'I 53 | 40.738 || 13°4 69°o o'53 o. 49'04 I. 3 I'58 4’38 || I. 29'59 IO 27. I I WR R I 5 || 30-545 4o’ I 58 I4'8 69'6 o'55 O. 45'91 I. 34°7 I – f * º L | 16 || 30-107 | 40'158 22-6 || 77.8 o'65 3. 55'77 I. 35’ I 5 5°oo I. 29'93 | I 28. I I | L | R I 5 || 30-7 16 || 4o-ooo 5'4 || 70°2 | O'55 o. 46' 13 I. 34°49 - f * e L | 16 || 30-716 || 39'535 1.5 76.3 o'63 3. 55°52 I. 34'90 5°3 I º 12 July 5. I I | H | R 15 28'579 42 "Ooo 17' 5 72°3 o' 58 o. 43.86 1. 36.76 * "Z * © L I6 28'579 4I '757 I 8:8 73°4. o:6o 3. 56'90 I. 36:28 7 38 I. 29 I4 I 3 6. I 1 | L | L | 16 || 28.60o 4.1°743 16:9 72. I o:58 3. 57°oo 1. 36:38 – 7:6 . 28.86 |. R | 15 28:840 || 41-743 | 19.4 || 74’3 o'61 o. 43.95 1. 36.67 7.67 2 I 4. 15. Io | T | R 15 29' 175 4I ‘3oo 16-5 72°8 o'58 O. 42 II 1. 38'51 * I O" X • L | 16 || 29' 175 41.286 17.8 74°3 O'59 3. 59°oo 1. 38'38 Io'23 I. 28°22 I 5 |.. 18. Io JP L | 16 || 30-400 40’082 I6.8 73°9 o'59 3. 59' 34 1. 38'72 = | | | | * * R I 5 || 30-375 4 o'o82 177 || 74.6 o'60 o. 4 I '83 1. 38'79 - 1 1-07 1. 27.69 I6 | 19. Io WR R I 5 || 30-545 39'818 1918 76.6 o°62 o. 4o'27 I. 4 o'35 - T iſ " 8. L | 16 || 3 o'730 39.8.18 I6'6 73'2 o'58 4. O'44. 1. 39'82 II '35 I. 28'74. 17 | August 5. 9 |WR R 15 || 30-545 39:710 | 16.8 || 722 o'58 o. 38'42 * {3. – 15:29 | 1. 28.09 L | 16 || 311 18 39.7 Io 2O’8 76°4. o'63 4. 5’ I 9 I. 43°77 I 8 6. 9 | H | R 15 28-121 42 "Ooo 16:9 727 o'58 o. 36.18 1.45:24 – I 5'5o . 3o'I I L | 16 28'12 I 42'84o 18-6 || 74.4 o'60 4. 7'40 I. 45'98 x o” ‘ooô46; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3’. 17”. 11. -º-º- The numerical value of the Sum of Equivalents in column 1 i = Wire Interval + (sum of Micrometer-Readings – 68). K 16" 780 + sum of . Level-Readings The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1889 the adopted Instrumental Constant was 2.20"62 until July 19 ; from August 5, 2.21"42. 2. Definition very poor; 2nd bisection a mere estimation. 11. Very faint ; scarcely visible. 13. Very faint and diffused. The reading of micrometer A, position L, has been diminished 1 rev. 1. The reading of micrometer B was set down 41F-865. 8. Wery faint ; cloudy. 12. Unsteady. 14. Diffused. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886–1899. MERIDIAN ZENITH DISTANCES of y DRACONIS observed with the REFLEx ZENITH TUBE-continued. # Micrometer Readings. Level Readings, Sum of Equiva- Concluded 3. Day and Hour - -4-> lents for wire, Star’s Mean 3 of . ~ . . Tº § - for Micrometer- observed Star Zenith º Observation, : 5 # A. B. fig | Readings and Zenith Distance | Correction. Distance 3 1889. ; # .# div. div. 3.3 for Level- North. North Ž à & 5: 7". 7°. 3.3 Readings. 1889 'o. d ** W f / & f / f 9 w A f I August I7. WR. R. I 5 || 30-545 39'571 15-8 71.6 o'56 O. 36-07 I. 45°35 – 17'49 I. 28'24. L | 16 || 31°396 39'57 I 2 O 2. 75'8 o'62 4. 7' 52 I. 46: Io º 2 3 I. WR. R. 15 30°545 39'323 16.8 71.6 o. 57 O. 3 I '91 I. 49'5 I tº º - L | 16 || 31-688 39'323 I9'4. 74°4 || O'61 4. 8:25 I. 46.83 — 19:27 I. 28'90 3 September Io. WR. R. 15 3O' 54.5 39°34'O 1 5-7 71.2 o'56 o. 32: 18 I. 49'24. — I o'8 I. 28'91 L | 16 || 31760 39'340 22:7 78.3 o'65 4. 9.78 I. 48:36 9°89 & 4. I 2. AD | R. I 5 || 30-584 39°25o 15-6 7o'3 or 55 O. 3 I'32 I. 5 o' Io – I 995 I. 297 I L | 16 || 30-584 || 4o'569 2O-6 75'4 O-62 4. Io:64 I. 49'22 b e 5 I 3. A C*| L | 16 || 30-545 40-690 2 I to 75'9 o'63 4. I2 'O2 1. 50-60 — I O'o 8 I. 3 o'o8 R 15 29' 178 40-690 17:0 7 I'5 O'57 o. 3 I '91 I. 49' 5 I 9'9 º 6 I6. A C*| R. I 5 || 30-545 39'422 18.5 75'4 o°61 O. 33.62 I. 47°80 — 2 o'o.7 I. 28' 55 L | 16 || 31°744 || 39°422 | 18.5 || 75.3 o'61 4. Io'85 I - 49°43 7 I7. RW R 15 31 or 2 39°ooo I9' 5 77.3 o'63 o. 34’39 I. 47°o 3 – 2 O "I O 1. 27.81 L 16 || 31 or 2 4 o' I 18 I6'2 73°4 o'58 4. IO-2 I I. 48.79 8 I 8. JP L | 16 || 30-ooo 4. I* I 23 I 5'4. 727 o'57 4. Io'O9 1. 48-67 - 2 O' I I. 28.66 R I 5 28-778 4. I ‘I 23 I 92 76.3 o°62 O. 32°52 I. 48'90 3 º 9 2 O. AD | R | 15 28:739 4 I ‘IOO 17:6 767 o°61 o. 31'46 I. 49.96 * 2 (T) * tº L | 16 28:739 42°408 I 4-8 74°3 o:58 4. Io' So I. 49'08 2O’og I. 29°43 IO 25. A C*| R 15 3O' 54.5 39'382 2 I ‘5 78.2 o-64 o. 32.98 I. 48.44 - I C) * I. 28- L | 16 || 3 I-737 || 39:382 ‘5 | 73°4 o'56 || 4. Io'o I I. 48°59 9'99 53 I I 26. R R | I 5 || 30°545 || 39°333 | 199 || 79.2 o'64 o. 32 'I 5 I. 49'27 — 19-97 I. 28.89 L | 16 || 31°779 || 39°333 | 12:4 || 7 || 7 | o'54 4. 9.87 I. 48:45 I 2 October I O. R | R. I 5 30°545 39°372 2 I ‘O 79°9 o'65 o. 32.82 1. 48.60 ame iſ 2". " © Lº ºf L | 16 31-632 39°372 I2 5 7I 3 || O'54 4. 8'o6 I. 46-64 18-97 I. 28.65 I 3 | November 13. RW L | 15 38°ooo 44'568 22'4. 83°o o'68 4. 5* I 3 I. 43°7'I — I 2°47 I. 3 o'84 R I4 37°436 44'568 I I-6 || 72°3 o'54 o. 38'52 I. 42'90 I4 December 19. H R. I 5 26'992 || 44°ooo 6-7 | 68.8 o'49 o. 50-69 I. 3 o'73 — O'83 I. 3 o'2O L | 16 || 26:992 43'088 25'4. 87.1 o'73 3. 52 '74. I. 3 I'32 x o” ‘oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3' 17"I 1. 2'.21’’ ‘42. The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 681) x 16" 78o + sum of Level-Readings The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1889 the adopted Instrumental Constant was 2.20"-62 until July 19 ; from August 5, GREENWICH OBSERVATIONS, 1904.—APPENDIx I. {G} 10 MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCES of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. # - Micrometer Readings. Level Readings. Sum of Equiva- Concluded 5 Day and Hour e --> lents for wire, Star's Mean ‘. . of : . . Tº # , for Micrometer- observed Star Zenith : Observation, g ă É A. B. ": T. Readings and Zenith Distance | Correction. Distance 3 1890. § | 3 || 3: div, div, 33 for Level- North. North c .# % = 7" 7. t Sº 3 Readings. 1890°o. Z! O Pi— e º ºr <3 - d h 6; £6 4. f / f A M 6 A / 4. f / I May 3o. I 3 || AD | R | I 5 25'890 44' 65 O 17°o 77.2 o'o I o. 43'23 I. 2 I "OO º tº L | 16 || 25.890 || 42'591 I4'o 74°8 o'57 3. 25’75 I. 2 o'92 + 7"O2 I. 28'28 2 June 7, 13 ||WR. R. I4 || 39°440 42-700 2 O 2. 78.2 o'64 o. 40-99 I, 23’93 - º 8. I 5 39'44O 4O'977 I4'4. 72°4 o' 5 3. 28'92 I. 2 4°og 3 18, 12 AD | R 15 27.273 || 42:800 || 17-8 || 74.6 o'60 o. 35' 39 I. 29°44 - e L | 16 || 27:273 41-630 I 5'8 73°o o' 57 3. 32°83 I. 28 ‘oo + I to 5 I. 29.77 + 19. 12 HT | L | 16 || 28°ooo 40-888 I 5' 3 72°9 o'57 3. 32°57 I. 27.74 - º R I 5 29.277 40-888 19°o ,763 o'62 o. 36-95 1.27-88 + o'73 I. 28'54. 5 2c. 12 | H | R I 5 28°o 59 42-ooo | 18-6 75°o o'60 O. 35’ I 5 1. 29'68 - - (T) * • 2 ö" L | 16 || 28'059 | 40-805 I5'o | 72°o o'56 3. 32° 17 I. 27'34. H o'4I I. 28'92 6 24. 12 | H | R | I 5 29'038 4I ooo 18:3 74: I o'60 O. 34.79 I. 3O'O4. e & L | 16 29'038 39'930 16-8 || 72.9 o'58 3. 33°93 I. 29' Io o'83 I. 28.74 7 26. I2 AD R 15 30'I 17 | 40'000 | 18-0 - 74.6 o'60 o. 36:13 I. 28.70 — I’. I. 28'o L | 16 3o. I 17 38-92.2 16' 5 73-8 o' 58 3. 35 “I 2 I. 3 o' 29 45 e 5 8 July I. I I L | L | 16 || 30'Ooo 39' 147 16-5 73-8 o'58 3. 36-94 I. 32 II – 2 I. 28'08 R | I 5 3 o'785 39' I 47 17'o 75'2 O'60 O. 33°o I I. 3 I-82 99 . 28'9 9 29. 9 | H R I 5 26°499 43'Ooo 2 O" 2 76°o o-62 O. 25.77 I. 39'o6 — Io-64 I. 2866 L 16 || 26°499 || 43'092 || 15'5 718 o'56 || 3.44:37 I. 39'54 I O | August 7. 9 SD | R. 15 26-947 42.7 oo 18.5 74°5 o'60 o. 28-24 I. 36'59 – I 2 ° I 27:27 - L | 16 || 26-947 42-856 I 5'4 71°o o'56 3. 47'92 I. 43'09 57 - -, . I I 20. 8 || L | R 15 26-566 42-700 I 5'o 72°2 o'56 o. 2 I-8 I I. 43'O2 – 14-81 I. 27°42 L | 16 || 26'566 || 43' 134 || 2 o'o 77°o o'63 3. 46-27 I. 4 I 44. 12 September 8. 7 || AD | R I 5 26:43 I 42-700 I6'o 71°8 o'57 O. I 9'55 I. 45'28 — 16.6 I. 27.6 L | 16 26:431 43'385 18-6 || 74.4 o'60 3.48 I 8 I. 43°35 9 º 3 I 3 15. 6 | H | L 16 || 28°ooo 41 '908 9°3 75-6 o-61 3. 49'73 I. 44'90 — 16:90 I. 28' 55 - R 15 27'180 41°908 74°o O'59 O. 18.84 I. 45'99 ſº I4. 16. 6 WR R 15 26.438 || 42:700 7-7 | 73°2 o'59 o. 19.68 I. 45’ I 5 — 16: I. 28-8 I L | 16 26.438 43’556 || 17-7 | 73°6 o'59 || 3. 51-16 I. 46.33 93 I. The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 681) x 16" 780 + sum of Level-Readings x o”“oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3’. 17”. 11. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1890 the adopted Instrumental Constant was 2.4”-83. -- 3. The reading of micrometer A was set down 32°273. 6. The reading of micrometer A has been diminished 2 revs. 6, 9. Very diffused. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARs 1886–1899. 11 MERIDIAN ZENITH DISTANCES of y DRACONIs observed with the REFLEx ZENITH TUBE–continued. š Micrometer Readings. Level Readings. Sum of Equiva- Concluded # Day and Hour º --> lents for wire, Star's Mean ‘5 of -: . . . 5–3 for Micrometer- observed Star Zenith : Observation, §: 3 É A. B. r; gº Readings and Zenith Distance | Correction. Distance •S ; ; §: div. div. # 5 for Level- North. North à à | * > 7". 7". 33 Readings. 1891 'o. - d h * / / f / A / / / / f /f I June 16. 12 ||WR} R 15 27-700 42-700 8'o 65’2 | O'47 1. 31'o6 I. 23'58 e P-y º ... I - L | 16 27.700 4o'884 27.2 84'4 O'72 4. I7'97 I. 23:31 + 4*76 I. 28'2 I 2 17. 12 |AM R I 5 27.693 42-700 8.7 65°o O'48 I. 3 o'97 I. 23.69 * g g L | 16 || 27.693 4O'923 269 82.8 o'71 4. I 8:50 I. 23-84 + 4'44 1, 28.21 3 19. I2 | H | R I 5 28-302 42 "Ooo 8:8 637 o'47 I. 29°43 I. 25°23 ! ~. Q - g - L | 16 || 28'302 40°285 24.8 79.7 o'68 4. I7-98 I. 23° 32 + 3.80 1.28 O8 4. 25. I2 WR R I 5 27-564 42 700 8-8 64'8 o'48 I. 28'82 I. 25'84 + I - I. 28: 56 L | 16 || 27-564 4 I-263 27.8 83.8 o'72 4, 22°o 5 I. 27°39 94. zo 5 5 27. 12 AM | R I 5 27°518 42-700 8-6 65.3 o'48 I. 28'O4. I. 26'62 1 - . * A A L | 16 27:518 4. I'323 27-8 83. I o'72 4, 22:28 1. 27.62 + 1:32 - 1. 28'44. 6 July I. I2 | H | R I 5 28:24.1 42 "Ooo 97 66°o º I. 28'44 I. 26'22 s , L I6 28:24.1 40.657 26°o 81.5 o'69 4. 23'20 I. 28'54 + O." IO I. 27-48 7 3. I I | L | R. I 5 || 27°414 42 7 Oo I 2" 2 68-6 or 52 I. 26' 34 I. 28.32 – o' e L | 16 || 27-414 || 41-435 23.7 | 8o'5 o'67 4. 22:36 1. 27.70 O'5o I. 27°5 I 8 4. II |A C*| L | 16 || 27-418 41°497 26. I 92°2 o'76 4. 23:56 I. 28'90 — o'80 I. 28° 2 R I 5 28'569 4. I'497 9.8 66-2 || O'49 I. 25 SO I. 29' 16 e 3 9 6. I I | H R 15 28:088 42-ooo 9.2 | 66°o o°49 I. 25-86 I. 28.8o – T * ſº L | 16 || 28-o88 40-828 26-4 82°9 o'71 4. 23’53 1. 28.87 I '40 I. 27'44. IO 9. I I AM R I 5 27.282 42 7oo 8.7 66-2 o-48 I. 24'O7 I. 3 o'59 a- ? " - L | 16 27.282 4 I'790 || 25'9 83.2 o'70 4. 26. I4 I 3 I ‘48 2' 30 I. 28.74 I I Io. I I | H | R I 5 27.062 43°ooo 9°7 66.4 o'49 I. 2 5 4 3 I. 29°23 •- 2 * º L | 16 || 27.062 4. I-612 23'2 8o'o o'67 4. I9'44 I. 2478 2'58 (1.24'43) I 2. II. II | WR R I 5 27:454 42:700 I O'O 66-8 o 50 I. 26'99 1. 27.67 sº- 2 ° e L | 16 || 27°454 || 41'516 24'6 82.6 o'69 4. 24'42 I. 29.76 2.86 I. 25-86 I 3 13. Io |A|C*| R 15 28.371 4. I* 5 I 7 I 2 "I 68.3 o'52 I. 22°53 I. 32° I 3 – 2 * º L | 16 28.371 40-61 I 23' I 79.6 o'66 4. 24°58 I. 29-92 3'42 I. 27.6 I I4. 14. Io | H | R 15 28-135 | 42-ooo 12:5 68.8 o'53 1. 26:69 I. 27°97 – ?" • A- L | 16 || 28-135 4o’909 24'4. 8o’8 o’68 4. 25.65 I. 3O'99 3'70 I. 25.78 I 5 17. Io |A C*| L | 16 || 28-12o 41'o63 23.7 78.4 o'66 4, 27°46 1. 32°8o – 4' 5 I. 29 '93 R | 15 28-616 4 I ‘O33 I 2.6 67.5 o'52 I. 18°53 I. 36' 13 4' 54. . 29 '9 I6 23. Io WR R 15 27:163 42-700 I O'8 68.4 o'51 I. 2 I "I I I. 33'55 – 6: Io I. 27°2 I L | 16 27, 163 42°oo4. 24'4. 81.8 o'69 4. 27°73 I. 33’O7 e 17 3o. 9 |AM R 15 27'08o 42'70o Io'5 69'o o'51 I. 2 o'72 I. 33’94 - '7" º L | 16 || 27'08o 42-213 22-6 80.8 o'67 4. 29'82 1. 35' 16 7.82 I. 26'73 18 || August 5. 9 HT | R I 5 26'732 43-ooo Io'o 68.3 o' 51 I. I9'91 I. 34*75 - ſh" t L | 16 || 26732 42'604 23.8 8 I. I o°68 4. 3O'54 1. 35'88 9'I 4. I. 26' 18 The numerical difference between this sum of Equivalents and the § Instrumental Constant is the star's Z. D. North. During the year 1891 the adopted Instrumental Constant was 2.54"'66. The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 65) x 16”78o + sum of Level-Readings x o'''ooã46; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3' 17"11. 5. Very diffused and tremulous. 14. Very tremulous. Io, 14. Very faint and diffused. 15. Very diffused ; 2nd bisection uncertain. II. Image bad. 16. Invisible at times. 12 MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. # Micrometer Readings. Level Readings. Sum of Equiva- Concluded § Day and Hour * --> lents for wire, Star’s Mean 3. of . ~ | ". 5– for Micrometer- observed Star Zenith º Observation, g 5 É A. B. r: ; Readings and Zenith Distance Correction, Distance & 1892. ; : # div, div. 3 .* for Level- North. North ź à || 3 || > 7" 7°. 53 Readings. 1892'o. d h 4./ 4 I July 22. IO | L | R. I5 7:723 I 3'300 23.6 8o:6 o'67 O. 1%84 i. 3ío.6 & 4 f f { L | 16 7:723 | 12:457 | Io:8 || 67.7 or 51 3. 20-64 I. 3 I ‘74. — 370 I. 27.70 2 30. 9 L | L | 16 6.720 13:468 I 3-2 69°o o'53 3. 2 o'79 I. 3 I-89 g g R I 5 7'39 I 13°468 24'2 80.6 o'67 o, 15'08 I. 33.82 – 5-64 I. 27°22 3 || August II. 9 |AM R 15 7'496 I 3'300 23'5 80.2 o'67 O. I4'O3 I. 34.87 tº “. L | 16 7'496 12.798 I O'O 66-2 O'49 3. 22 °54. 1. 33°64 – 8: I 2 I. 26'14 4. 15. 8 CD | R. 15 7-322 I 3'300 24'3 79.6 o'67 O. II* II I. 37.79 g e L | 16 7'322 | I 3 'O7I 12:9 67.9 o'52 3.24°22 I. 35' 32 – 8:84 I. 27.72 5 || October 22. 4 |TH | R 15 7'333 I 3'300 18-4 8o'o o°63 o. I 1 -25 I. 37-65 © L | 16 || 7-333 || 13 I 25 || 14-6 || 76.2 o'58 || 3.25°37 ; :4; – 994 | 1.28 or The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 201) x 16" 780 + sum of Level-Readings x o”oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3' 17"11. g * w; The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1892 the adopted Instrumental Constant was 1'.48"'90 2. The reading of micrometer A, position L, has been diminished 1 rev. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886–1899. 13 MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. § Micrometer Readings. Level Readings. Sum of Equiva. Concluded # Day and Hour * --> lents for wire, Star’s Mean ‘35 of * . . . Tº 5–3 for Micrometer. observed Star Zenith ca Observation, £ | 5 || 3 A. B. H. S. Readings and Zenith Distance | Correction. Distance 3 1893. § £ sº div. div. 3 º for Level- North. North % à É : 7". ''. āş Readings. 1893'o. | - d h M/ Aſ * { f / 4 / 4 // I May 24. 14 | H | L | 16 7-700 I I- 2 I 3 8-O 65.8 o'48 . 32°9 I I. I I I 3 + 16-16 I 26.66 R. I 5 Io’97 I II 2 I 3 26-3 84'o o'71 . I I '92 1. 9.86 2. 25. I4 || B | R. I 5 8-932 I 3-3oo 27-9 84-8 o'73 I. I I '74. I. I O'O4 º --. - L | 16 8'932 9:816 8'2 64'4 o'47 . 3O' I 3 I. 8'35 + 1 5'85 I. 25 OS 3 3o. I 3 || B | R. I 5 8’495 I 3-3CO 26'6 85.3 o'72 • 4'4O 1. 17:38 e * - L | 16 8’495 Io'464 7'4 | 66.3 o'48 . 33.68 I. I I-90 +14:30 I. 28'94 4 June i 5. I 3 || WB. R 15 8-5 Io I 3' 300 3O'3 93.7 o'80 . 473 I. 17-05 , º • I r —s L | I6 8-5 Io II 724 I 3-3 63'o o°49 . 38.31 I. I6'53 + 12'38 I. 29' 17 5 I 3. I2 J R. I 5 8’408 I 3'300 32°o 87.1 o'77 • 2'99 1. 1879 e º ? L | 16 8’408 Io'893 5°2 61°o o'43 3. 39°37 I. I 7°59 + 9'82 I. 28°o I 6 14. 12 |TH | R 15 8’425 I 3'300 32-8 87°5 o'78 I. 3'29 I. I 8:49 + 9°50 I. 28'52 L | 16 || 8:425 | Io'994 4' 5 59° 5 || O'4. I 3. 4 I 33 I. I 9'55 7 I 5. I 2 | AC R 15 1 o'652 I O'994 33°7 88.2 o'79 . I-97 1. 19-81. , ſº * tº * L | 16 || Io:652 8-964 4' I 58-9 || O'4 I 44-64 I. 22.86 + 9:18 I. 3O'52 8 I9. I2 | AC | L 16 7'999 II 503 3' I 57.2 o' 39 . 42'70 I. 2 O'92 ~~ e R 15 IO' I I 5 I 1-503 35' I 88.9 o'80 I 5 I 1. 20:27 + 7.90 1.28 5o 9 2 I. I 2 | H | R 15 8'502 I 2'990 33'O 88.9 o'79 . 59' 38 I. 22 °40 tº r — Sº a L | 16 8' 502 Io'990 3-6 6o'o O'41 . 42'55 1. 2 o'77 + 7.26 I. 28.85 I O 27. I 2 | AC L | 16 8-5 or II "O45 3' I 6o'I o°41 . 43°46 I. 2 I-68 gº © R I 5 I O'435 I 1 o45 || 32-6 89.2 o'79 . 59 18 1. 22-60 + 5°34. I. 27′48 I I 29. I I | H | R. I 5 - 8:390 I 3 'Ooo 33°7 90°o o'80 . 57.68 I. 24. Io ſº to L | I 6 8:390 11:388 4."O 60-6 o'42 . 47 '37 I. 25'59 + 4*70 I. 29° 55 12 July 2. I I | CD | R 15 8'O44 I 3'30O || 33' 5 88:o o'79 . 56-90 1. 24.88 ... º. º. & L | 16 8-O44 II 537 5'O 58-6 o'41 • 44'O5 I. 22°27 + 3°77 I. 27°35 I 3 5. I I WB | R 15 8-125 I 3' 300 37'3 87.6 o'80 . 58-27 I. 23° 5 I º g L I6 8-125 II ‘S79 I4'5 60'4 o'48 . 46' 19 I. 24°4 I + 2 84. I. 26.8o I 4 Io. Io | CD R | 15 7'961 I 3'300 33-6 887 o'79 . 55' 52 I. 26:26 o L | 16 || 7.961 I 1865 || 2:7 57.8 oºg 3.48-14 :::::: + +3° i. 27.62 - I 5 II. Io | H | R. 15 8'28 I I 3-ooo 33 "O 87.2 o'78 . 55'84 I. 25'94 e * L | I 6 8,281 II 585 6-o 61 I o'43 . 48-85 1. 27'07 + I'O4. I. 27°55 I6 I2. Io B | R | 15 8'O34. I 3'300 29-9 85-7 o'75 O. 56-69 I. 25 °og & & L | 16 8'O34. I I-694 6-4 62-6 o'45 . 46°o 5 I. 24'27 + o'76 I. 25'44. | 17 17. Io | AC R 15 7.875 I 3'300 29'9 86-8 o'76 O. 54."O4. I. 27°74. t tº L | 16 7.875 12 oz.6 6°o 63.2 o'45 . 49-63 I. 27°85 — o'64 I. 27. 16 I 8 20. Io B | R 15 7:676 I 3' 300 28°4. 847 o'73 . 50-67 I. 3 I II * ! ~ Q. - l L I6 7.676 I2°300 7.8 . 64' 5 O'47 . 5 o'74. I. 28.96 – I ‘45 I. 28 59 The numerical value of the Šºm of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 18r) x 16" 780 + sum of Level-Readings x o”oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3' 17” II. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1893 the adopted Instrumental Constant was 2.21”.78. 2. Very faint; cloudy. * 6, 7. Diffused. 14. Very diffused. 15. The integral number of revolutions of micrometer B, position L, has been Supplied. 16. Scarcely visible. The reading of micrometer A has been increased I rev. 14 MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCES of y DRAGONIS observed with the REFLEX ZENITH TUBE—continued. ă Micrometer Readings. Level Readings. Sum of Equiva- Concluded g Day and Hour i.e. --> lents for wire, Star's Mean ‘. of 2: . . . § – for Micrometer- observed Star Zenith ſº Observation, § | 5 | # A. B. 'ſ Readings and Zenith Distance | Correction. Distance & 1893. à || 3 || 3: div. div. #5 for Level- North. North c .3 3 • F-4 7 7". S. 5 Readings. 1893 °o. d h # / f f f Z # / ſ & & 1, I July 27, 9 J R. 15 773. 3.375 *7 $2.4 o'66 O. 47'74 1. 34.94 — 3'20 . 3O'O 5 L | 16 7'731 | 12:454 || Io'o 6o'7 o'46 3. 54°23 I. 32 '45 2 August 4, 8 ||WB| R 15 7'723 || 13:300 $34 32.4 oz; o. 5 I ‘48 I. 3 o'30 — 5’ O2 . 27' 20 L | 16 7:723 12:560 II 5 65: I o'50 3. 55'92 I. 34.’ I 4 3 9. 8 || B | R 15 7'429 || 13:300 297 | 83°4 o'73 o, 46-53 I. 35'25 – 6: 8-88 L | 16 7'429 12°887 | 9.3 63'O o'47 3.56°44 1. 34.66 O8 ... 2 4. Io. 8 ||WB. R 15 7-718 I 3'300 || 3 o'7 84-3 || O'74 o. 5 I 38 I. 3 o'40 – h" L | 16 7-718 12-63 I 12-0 | 61-6 o'48 3. 57°oo I. 35'22 6'26 . 26'55 5 September 4, 7 | HF | R 15 7:200 I 3'300 3O'7 83'I o'73 O. 43°07 1. 38-85 5 - f \" º L | 16 || 7-2 oo 13°317 99 || 65’2 o°49 3. 59'84 1. 38'o6 9:63 . 28.83 6 7. 6 CD | R 15 7,410 | 13:300 26.8 || 81.8 o'70 o. 46.18 I. 35.60 © º L | 16 7'4. Io 13°o 16 I O'O 65°o o'49 3. 58.31 I. 36.53 – 9'90 .* 7 || October 3o. 4 || CD | R º 7-506 I 3'300 27.2 88-o o'74 o. 47.82 1. 33.96 — fº " º i. ió | #:06 || 13788 || 4.5 || 65.0 oº; 3.56:06 I. 34:28 6-17 | 1. 27.95 The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 18F) x 16" 780 + sum of Level-Readings x o”“oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = + 3' 17" 'I 1. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1893 the adopted Instrumental Constant was 2.21"'78. 1. Very diffused. 7. Very faint. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886–1899. 15 MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEX ZENITH TUBE-continued. # - Micrometer Readings. Level Readings. Sum of Equiva- Concluded # Day and Hour . --> lents for wire, Star’s Mean *; of H . . ; 5– for Micrometer- observed Star Zenith º Observations, g 3 É A. P. 3 & Readings and | Zenith Distance Correction. Distance 3. 1894. # | # se div. div. 5 .# for Level. North. North - Ž ?. - - à & : 7". 7". §§ Readings. 1894'o. d h 6 6 4./ 6 4 // / / / . // A // I | January 18. 22 CD R 15 8.989 I 3'30O 4-' 66.1 o'4 I. I 2°43 I. 9°35 - I 8: I. 28'08 L | 16 || 8-989 9'933 26:9 88°4 || O'74 || 3.33'32 ...;; +1854 i. 89 2 July II. I I | H | R I 5 || 4o'252 I4°ooo 27.6 84'o o'72 o. 38'51 I. 26.5o 8* I - L I6 40°252 I2°432 I O'O 66.7 O'50 3. 30.76 I. 25.75 + 2 oz 1. 28’ I 5 3 25. 9 || WB - R I 5 | 40-865 I 3' 300 74°o 18-2 o'59 o. 36-92 I. 28-09 — I '8o I. 28:26 - L | 16 || 4 o'865 I2. I 88 167 72°6 o'58 3. 37'O3 I. 32'O2 4. 27. 9 |DE | R 15 | 40870 I 3'300 I9' I 739 o'60 o. 37'02 . 27'99 – 2:30 I. 25'93 L | 16 || 40870 I I'971 17.7 72°4 o'58 3. 33°47 I. 28.46 5 28. 9 | H | R. 15 42-193 12 ooo 20:8 75°o o'62 o. 37°42 I. 27°59 – 2'55 I. 25" 53 L | 16 || 42° 193 Io:655 17°o 71°8 o'58 3.33'58 I. 28'57 tº dº *" . 6 || August 15. 8 || B || R. 15 4o'602 I 3'300 2 I-3 77's o:64 - O. 32°55 I. 32°46 — 6' I. 2 " " 'ſ 2 L | 16 || 40-602 12'407 I4°o 7O'4 || O'54 3.36:25 I. 3 I ‘24. 33 . 25.5 7 September 1. 7 | B | R 15 4 o'4 II I 3 '300 18:3 74'2 o'60 o. 29°32 1. 35'69 — X" o L | 16 || 4o'4II 12:898 I6'o 7 I’9 || O'57 || 3. 4 I ‘3 I I. 36°30 8'66 I. 27'34. 8 I 2. AC | R. I o: I 3 ° 2 O I 2O"O o o:6 o. 28°2 I. 36.78 e e 7 L ł ::::: :::: O IA. "O 77.5 & ź e : I. 3 7 – 9:40 I. 26'18 | 49.344 5 4'o 7 I-7 o'5 3. 39'3 34’37 9 || October 1. 7 | H | R 15 4O'594. I 3°ooo 16-6 || 75-8 o'59 o. 27°34. 1. 37.67 — O " º . . - L | 16 || 4o'594 | 12-698 || 15°o 74.4 o'58 || 3.41.04 I. 36:03 9°3o | I. 27°55 of Level-Readings x o'"ooé46; where the Wire Interval for wire 15 is zero, and for wire 16 = 3’. 18".78 [but for Jan. 18, 3’. 17”. 11]. between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. Durin 2'.5” or [but for Jan. 18, 2'.21”78]. The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings — 52+ [but for Jan. 18, -18°) x 16" 789 + sum The numerical difference g the year 1894 the adopted Instrumental Constant was 1. Very faint. - I, 4. The reading of micrometer B, position, L, has been diminished I rev. 3. Very diffused. July 10. The wires were found broken. 6. Very windy. 16 MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. # Micrometer Readings. Level Readin º Sum of Equiva- Concluded # Day and Hour º ... lents for wire, Star's Mean ‘5 of +: . | ". F. : T for Micrometer- observed Star Zenith ſº Observations, § | 5 || 3 A. B. Tº ºf Readings and Zenith Distance Correction. Distance 3 1895. ; # 2 div. div. £5 for Level- North. - North à à # : 7°. 7". ă 3. Readings. 1895'o. d h - 6 ¥6 f A / 4 A / f / , a I May 30. 14 | H | R 15 19 178 35°ooo 2 I-8 767 o'64 I. IO'75 I. IO-50 ~ | . . . L | 16 || 19:178 3 I-5 18 I6. I 71°o o'56 3. 3 I ‘O2 I. 977 + I 5'30 I. 25*44. 2 31. 14 AC L | 17 | 5.364 33603 | 153 || 706 o’ss 3.30-37 I. 9"I 2 " . . . * ~ a • R. I6 872 I 33'603 2 o'9 76.3 o'63 I. Io:60 I. Io-65 + 14.98 I. 24. s: 3 June 5. 13 | B | R 15 I4°75o 39'145 || 2 o’8 77°5 o°64. I. 5'99 I. I 5:26 r a • º - L | 16 || 14-750 36. I 14 I4-6 7 1-2 O'56 3. 33°84 I. I.2°59 + 1 3:38 I. 27°3 I 4 6. 13 CM R 15 19'o69 || 35-ooo 22°o 79.2 o'65 I. 8-93 i. i*32 ...-a -- L | 16 19:069 || 31°793 14-7 || 71 7 o'56 3. 33.80 I. I2'55 + 1 3'o6 I. 25'50 5. 7. 13 | H | L | 16 | 19°ooo 31°923 || 14-3 || 706 o'55 3. 34-82 I. I 3'57 º • . R I 5 22:07.5 3 I '923 2 I "O 768 . o.63 I. 77 I I. I 3 '54. + I2'74. 1. 26.30 6 8. I 3 | AC R | 15 22:078 || 31924 227 | 77.6 o'65 1. 7.80 I. I 3 '45 • * * * * & L | 16 22 oz8 28'924 14-8 7o'o O'55 3. 36. I4 I. I 4'89 + I 2:42 I. 26'59 7 13. 12 | HF | R 15 25'08o 29°ooo 20:7 8o 5 o°65 I. 9°I I I. I2. I4. º - L | 16 || 25°o8o 25'8 Io Io'o 67°o o'50 3. 34.2 I I. I2-96 + Io'78 I. 23° 33 8 18. 12 | B | R 15 2 I-820 32°ooo 3 I I 87.7 o'77 I. 4'87 1. 16:38 ~ * º L | 16 21.820 29, 186 6'O | 63. I o'45 3. 36 II I. 14.86 + 9°13 I, 24*75 9 19. I2 | H R 15 23'58o 3o-ooo 28:8 86°o o'74 I. O’8 I I. 2 O'44 & tº - L | 16 || 23:580 27.747 8°o 65.1 o'47 3. 4 I ‘52 I. 2 o'27 + 880 I. 29' 16 IO 24. I2 | H | R. I 5 || 23'541 3O'Ooo 29.7 85. O'74 I. o. 16 I. 2 I og © º L | 16 || 23'541 27-891 8 ‘o 64'o o°47 3. 43°27 I. 2 2 "O2 + 7"I 5 1. 287 I II July I. I I CD R 15 24-379 29°ooo 30:6 86.3 o'76 o. 57.46 I. 23.79 º o L | 16 || 24°379 27:161. 6.8 62°4 o°45 3. 45°o7 I. 23.82 + 4-88 I. 28-69 I 2 2. 11 | H | L | 16 24°ooo 27. 517 6'9 63-8 o'46 3.44. 70 I. 23°45 e -s. R 15 25'829 27' 517 3 I-2 87°o o'76 o. 56-90 I. 24' 35 + 4' 57 I. 28°47 I 3 4. I I | AC | R I 5 || 25.712 27' 517 3O'3 86.7 o'76 O. 54'95 1. 26.30 tº Q L | 16 || 25.712 25'961 6-6 63' I o'45 3. 47'3 I I. 26'o6 + 3’95 I. 3 o' I 3 I 4 6. I I | H | L | 16 || 26-ooo 25'472 6. I 62°o o'44 3. 43°92 1. 22.67 e ge R I 5 27-874 25'472 3 I'o 87.2 o'76 O. 56-90 I. 24°35 + 3°33 I. 26.84 I 5 8. II | AC R | 15 27'940 25'46o 34'9 88.7 o'80 O. 57.85 I. 23°40 e tº L | 16 27°940 23:637 6'8 61 ‘I o'44 3. 45-69 I. 24'44. + 2*7 I I. 26.63 I6 9. I I B | R 15 29'68o 23.625 32°5 87-1 || o'77 o. 56-22 I. 25°o 3 º e L | 16 29-680 2 I '955 6. I 60-6 || O'43 3. 46-64. I. 25°39 + 2 4o 1. 27°61 17 | August 6. 9 | AC R 15 23740 29°ooo 28' I 85. I o'73 O. 46.7 I I. 34' 54. — 4.86 º ke L | 16 || 23°740 28°416 77 65°o o'47 3. 55 43 I. 34’ I 8 4'8 I. 29'50 I 8 7. 9 | B | R | 15 24' 357 28°415 || 28-3 || 85.3 || O'73 O. 47' 25 I. 34."Oo — K'o& . 28' L | 16 || 24' 357 27768 6-8 63-8 o'46 3. 54'90 I. 33°65 5'o I. 28°75 The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 50) x 16" 789 + sum of Level. Readings x o”oo646; where the Wire Interval for wire 15 is zero, for wire 16 = 3", 18”78, and for wire 17 = 6.34"'95. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1895 the adopted Instrumental Constant was 2'.21”:25. 1. The reading of micrometer A has been diminished 1 rev. 6, 15, 16. Very diffused and unsteady. 7, 17. The reading of micrometer B, position L, has been diminished I rev. e 8. Observation hurried. 13. Diffused and unsteady. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886–1899. 17 MERIDIAN ZENITH DISTANCES of y DRACONIS observed with the REFLEX ZENITH TUBE-continued. ă Micrometer Readings. Level Readings. Sum of Equiva- Concluded 35 Day and Hour iº --> lents for wire, Star’s Mean *; of * , E - 5-; for Micrometer- observed Star Zenith g Observation, § 3. É A. B. º: £ Readings and Zenith Distance | Correction. Distance 3 1895. É # ? div. div. 3.5 for Level- North. North à - à ń. : 7”. 7". 3.3 Readings. 1895 'o. | d h // # ſ! ſ Al /l f // I August 12. 8 || WB. R 15 24'811 28°ooo 29°o 85'4 O'74 O. 479 I I. 33'34. – 6:02 I. 27. K8 L 16 || 24.81 I 27'327 7-9 63-8 o°46 3. 55' I I I. 33.86 . 27' 5 2. 19. 8 | AC R 15 23-827 29'Ooo 3O'4. 84-7 || O'74 o. 48° 18 I. 33 'O? — 7 °2 I. 26' I L | 16 || 23.827 28'300 9'O 63.2 O'47 3. 54'95 I. 33°7'O 7:25 e 4. 3 20, 8 | H | L | 16 || 24-ooo 28° I O2 9' 5 63-9 o'47 3, 54. 52 I. 33°27 – 7:40 I. 25.78 R I 5 24.725 28' I oz 29'4. 83'2 o'73 o. 48°17 I. 33°o8 5 4. 2 i. 8 || B | R 15 34.86; 28'o69 3 I'o | 84-6 o'75 o. 49'98 I. 3 I’27 – ’7” I. 2 4.' I S L | 16 24'865 27°169 8-9 62-7 || 0:46 3. 53°37 I. 32°12 7' 55 4 b 5 22. 8 || WB. R 15 25'852 27-ooo 32°o 86°o o'76 o. 48-61 I. 32°64 — 7°7 O I. 25.46 L | 16 || 25'852 26-274 9'O 62°o o'46 3. 54'92 I. 33.67 7.7 5'4. 6 23. 8 || S R I 5 25'81 I 27"Ooo || 3 I’o 83°o o'74 O. 479 I I. 33'34. — 7'85 I. 25-63 L I6 25'81 I 26'3 Io II "O 65°o O'49 3. 54.87 I • 33.62 º 7 24. 8 | H | R I 5 23.852 29°ooo 28-7 84°o o'73 o. 48° 58 1. 32°67 - > * - L | 16 || 23-852 28-209 8.7 64'o o'47 3. 53-84 I. 32° 59 8°oo I. 24'63 8 - - - - - 27. 7 | AC R I 5 24'672 28.207 29' I 85.2 O'74 O. 49°o 5 I. 32°2O — X" . . - L | 16 24'672 27'4O9 6:3 62.5 O'45 3. 54." I 5 I. 32°9o 8:45 I. 24.' I O 9 28. 7 |CM R 15 23.698 29°ooo 3I '7 87°5 o'77 o. 46'04 I. 35'2 I — X" e L | I 6 23.698 28°357 6-2 62°o O'44. 3. 53°7'O 1. 32°45 8.60 I. 25°23 IO 3o. 7 | H | R I 5 || 2:3:692 29°ooo 3O'o 84-7 || O'74. O. 45'91 I. 35' 34 — X* º L | 16 || 2:3:692 28'561 79 627 o'46 3.57°o 5 I. 35'8o 8'8o 1. 26-77 I I 31. 7 | AC | R. . I 5 24'I 32 28'572 29' 3 849 o'74. o. 46' 12 I. 35 “I 3 - X" P- - L | 16 || 24; 132 28°o39 8'o 637 o'46 3. 55.68 I. 34'43 8-90 1. 25.88 12 September 2. 7 | B | R I 5 23:659 29°ooo 29'2 837 o'73 O. 45°35 I. 35'90 - C)." IO I. 26'47 L | 16 || 23.659 28'560 8:8 63-5 o'47 3.56-49 I. 35'24. 9 e I 3 3. 7 || RC R 15 23700 29°ooo 34 88:o o'79 o. 46' Io I. 35’ I 5 = f\" e L I6 23.700 28'532 I 60°o O'42 3• 56-65 I. 35'40 9:20 I. 26-ob I4. 4. 7 | AC | R 15 24'092 28-553 || 3o'o | 84.4 o'74 o. 45"I 2 1. 36:13 — ſh" g L | 16 || 24'092 28: 155 | 8.2 | 62-4 o°46 3. 5695 I. 35'70 9:30 I. 26.62 I 5 6. 7 | B | R 15 24:466 28-275 29'5 84-6 o'74 o. 46'8o I. 34°45 — O' " I. 24.8 L | 16 || 24'466 27-699 || 8-5 63.4 o'46 || 3. 55'57 I. 34'32 9'5o I. 24'89 I6 7. 7 | DE | R. 15 24'760 28-ooo 31.1 85'4 o'75 o. 47'o'7 I. 34°18 — ſh" - L | 16 || 24'760 27:423 8’o 62-6 o'46 3.55'87 1. 32-62 9-60 | 1. 24.80 17 13. 6 J R 15 27.659 25°ooo 34°o 90.7 o°81 O. 45°43 I. 35'82 — o'8 I. 27°O L | 16 27°659 24-72 I 7'o 63.9 o'46 3. 59' I 7 I. 37'92 9°84. 7:03 I8 14. 6 B | R I 5 28°o 13 24'58 I 29'9 86.5 o'75 o. 44'28 1. 36-97 - — ſh" - L | 16 28°ol 3 24'277 5-6 62-9 o'44 3. 57-65 I. 36:40 9-88 I. 26-8 I The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 5or) x 16" 780 + sum of Level-Readings x o'''oot,46; where the Wire Interval for wire 15 is zero, for wire 16 = 3’. 18”78, and for wire 17 = 6'.34”9 Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1895 the adopted Instrumental Constant was 2.21"-25. 5. The numerical difference between this sum of 1, 6, 16. Very diffused. 5. Wery faint ; cloudy. 17. The reading of micrometer B, position R, has been diminished 2 revs. GREENWICH OBSERVATIONS, 1904.—APPENDIx I. {D} 18 MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEX ZENITH TUBE-continued. š w Micrometer Readings. Level Readings. Sum of Equiva- Concluded # Day and Hour e --> lents for wire, Star’s Mean *::: of -: º § – for Micrometer- observed Star Zenith º Observation, §: 5 É A. B. † : Readings and Zenith Distance | Correction. Distance 3 1895. ; E 9 div. div. £5 for Tevel- North. North à 3 à #: 7°. 7". 3.3 Readings. 1895'o d h - */ - 4. f / * f / 4 / 4 f / I | September 16. 6 |DE| R 15 24:612 28.000 || 31.8 89°o o'78 o. 44-61 I. 36-64 'o6 | 1. 27. I L | 16 || 24.612 27.748 5' I 62-3 o'43 3. 58-81 I. 37'56 – 9:9 . 27" I4. 2 20. 6 S R 15 24'822 28°ooo 3 I'o 86°o o'76 o. 48 I I I. 33' I4. s. e L | 16 || 24'822 27' 573 I 2 "O 66°o o' 50 3. 59:46 1. 38'2 I - I O'OO 1. 25.68 3 21. 6 | AC | R 15 25-643 26.999 || 294 | 86.9 o'75 O. 45°o? 1. 36.17 – Io:oo | I. 26'34 L | 16 || 25-643 26:653 6'2 63-6 o'45 3. 57.76 I. 36:51 - e 4. 3o. 5 || J R. I 5 22°oco 3 o' 595 32°o 86°4 o'77 O. 44'3 I I. 36-94 – 9:85 I. 26. L | 16 || 2 I-690 30'595 6-6 6 I'o O'43 3.57°55 I. 36:30 9 . 2077 5 || October 3. 5 H | R I5 23-645 29'ooo 27.2 85.8 o'73 o, 45° II I. 36'14 — 9'70 I. 26' 54. L | 16 || 23°645 28,639 7.7 66 1 o'48 3. 57' 59 I. 36°34 9 , 26°54. 6 | November 14, 2 | B | R 15 23:999 || 29'000 22.8 82:1 o:63 2.51% 1. 39.25 – 290 | 1. 27.06 - L | 16 || 23:999 27.885 I I "I 7 o’3 o' 53 3. 5 O'92 1. 29.67 7 18. 2 | W R 15 23.953 29°ooo 2 3'2 83’5 o'69 O. soº I. 3 I'o I - iſ " º L | 16 || 23.953 27-989 9'4. 69'5 O'5 I 3. 51:87 I. 30.62 I-84 I. 28'98 The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (Sum of Micrometer-Readings - 501) x 16" 780 + sum of Level-Readings x o'''ooô46; where the Wire Interval for wire 15 is zero, for wire 16 = 3’. 18"'78, and for wire 17 = 6'.34”95. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star’s Z. D. North. During the year 1895 the adopted Instrumental Constant was 2.21”25. 1, 2. Very diffused. 2. The reading of micrometer B, position R, has been increased 1 rev. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886–1899. 19 MERIDIAN ZENITH DISTANCES of y DRACONIS observed with the REFLEx ZENITH TUBE–continued. # Micrometer Readings. Level Readings, Sum of Equiva- Concluded § Day and Hour e --> lents for wire, Star's Mean , 3 of . : . º: 5- for Micrometer- observed Star Zenith 2– Observation # | 5 || 3 A. B. *: § Readings and Zenith Distance | Correction. Distance •S 1896. ; # £ div. div. #5 for Level- North. North Ž à | }. : 7". 7°. 33 Readings. 1896'o. 3. d h f f * f / Af & I June II. I 3 || B | R | 15 24'901 | 29'000 32°o 87-6 || 0-77 I. 6:23 i. 1; 35 & ſº . L | 16 || 24'901 26.361 3’5 6o’9 o°41. 3. 40°37 I. 1879 + Io'IO 1, 27'17 2. 20. 12 || WB. R 15 21'4oz 32-ooo 31-6 87.3 o'77 o. 57.8 I. 23" L | 16 || 2 I 402 29:760 7:6 63'o o'46 3. ś I. ;34% + 7' I 3 I. 27.58 3 26. 12 | B | R I 5 23°4 IO 3 o'Ooo 3 o'o 86.2 o'75 O. 57°97 I. 23-61 tº e L | 16 || 23°4 Io 28°o2O 4' 5 6 I'o o'42 3.34% 1.2.61 | "t 5'5 1. 27.76 4 July 20. Io B | R I 5 24-268 29°ooo 38°4 92°o o'84. o. 55.68 I. 25'90 ſº e L | 16 24-268 27.703 I’9 557 o'36 3. 52'22 :::::: – “to . .617 5 22. Io W L | 16 || 24-ooo 27.718 4'o 58.8 o'41 3.48°O2 I. 26:44 ſº te R | 15 25-344 27-718 35' 3 90°O o°8 I O. 52' I 9 I. 29'39 — 2-62 I. 25'30 6 24. Io | AC R | I 5 || 25'025 28 ooo 36-1 91 2 o'82 O. 5 I 58 I. 3O'OO & L I6 25 O25 26-837 I '9 56.9 o:38 3. 5O'4O I. 28'82 *-º-º-º: 3 I4. I. 26 27 7 August I. 9 || S | R. I 5 || 25°o 54 28°ood 42 "O 93°o o'87 O. 52 I 2 I. 29:46 tº * L | 16 || 25°o 54 26'930 I ‘O 56°o o'37 3. 52'44. 1, 30-86 — 5: IO I. 25 off 8 4. 9 || CD | R. I 5 25'972 27°ooo 36°o 92°o o'83 O. 50-70 1. 30.88 e - gº L | 16 || 25'972 26°og I o’9 57. I o'38 3. 5.277 ; :... – 576 sº 9 Io. 8 || EB | R I 5 || 25'950 27°ooo 34°2 9I'O o'81 O. 50'3 I I. 3 I-27 & g L | I6 25'95o 26-232 I '8 58-7 o'39 3. 55-78 I. 34'2O – 7:O2 I.-2 5'72 IO 11. 8 W R 15 25.763 27°ooo 36°o 92°2 o'83 o. 47-2 O I. 34'38 o * * L I6 25'763 26'22'o o'9 57.8 o:38 3. 52'43 I. 3O'85 — 7°2 I I. 2 5 4 I I I 12. 8 CD R | 15 25.820 27°ooo 34°9 90.6 o'81 O. 48' I 3 I. 33°45 ſº e L I6 25'82O 26.294 3'3 59°o O'4O 3. 54.66 I. 33'08 * 7 4O I. 25 87 I 2 25. 8 || W R 15 25.707 27°ooo 27. 83.8 o'72 o. 46. I 5 I. 35'43 º • 23 L | | 6 || 25.707 26'592 8-9 65.2 o'48 3.57°84 1. 36-26 – 9 52 I. 26°33 13 31. 7 || W R 15 || 25-612 27°ooo 31°o 88.2 o'77 o. 44-60 1. 36.98 - te * - L | 16 25'612 26.638 6'2 63'5 O'45 3. 56'99 I. 35'4. I — I o'24. I. 25-96 I4 September 3. 7 || W R | I 5 || 25-632 27°ooo 26°o 83.8 o'71 O. 44'87 1. 36'71 tº g L | 16 || 25-632 26-65 I | 89 | 66°o o-48 || 3. 57-57 ; ::, -io's 25.8 I 5 19. 6 | H | R 15 24:612 28°ooo I "2 78.4 o'64 O. 44'47 I. 37: I I º º L | 16 || 24'612 27.673 3-6 7 I I o'55 3.57-67 I. 36'09 — I I 34 I. 25.26 I6 || October 5. 5 || B | R. I 5 24.433 28°ooo 18-3 || 78°o o-62 O. 4 I '44. I. 4.O.' I 4. º º L | 16 || 24'433 27'90o I 3-7 | 73°o o' 56 || 3. 58.48 ...; –1986 | 1.2766 17 9. 5 || B | R. I 5 24*72O 27-900 2O" 78-7 || 0:64 o. 44:61 1. 36-97 i.e. g L | 16 || 24.720 27.600 I 2 3 7 o’7 | O'54 3. 58°25 1. 36.67 — Io' 54. I. 26-28 18 November 5. 3 | AC R I 5 25-849 27°oo I 23:9 || 85°o o'70 O. 48° 52 I. 33'06 & gº L | 16 || 25-849 26-239 7'o 68.2 o'49 3. 54'3O I. 32.72 — 6'34. I. 26'55 The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 5or) x 16" 78o + sum of Level-Readings x o”-oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = 3'.18”.78. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1896 the adopted Instrumental Constant was 2'.21"'58. . 1. Wires not vertical. 2, 5, 7. Very diffused. 3. The reading of micrometer A has been increased I rev. 5. Very cloudy. 8, 10. Diffused. 9, 12, 16. Cloudy. MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. d5 # Micrometer Readings. Level Readings. Sum of Equiva- Concluded # Day and Hour e --> lents for wire, Star’s Mean º of : T. § – for Micrometer observed Star Zenith £d Observation, g 5 É A. B. r; gº Readings and Zenith Distance | Correction. Distance & 1896. ; , ; g div. div. º º for Level- North. North à à § : 7°. 7" É Readings. 1896'o. d h f / & # / Z f f f / f f / I November 6. 3 || B | R. . I 5 26.650 26-239 2 3'2 85°o o'70 O. 49' I 7 I. 32°4. I 6- te * * e e ſº º — or I 4 I. 26'23 L | 16 || 26:650 25'413 8’4 || 702 || 0:51 3. 53'91 I. 32°33 e B | R. I 2 º' " 27 ‘OOO I O' 82'2 | O'6 O. § O' I I, 2 I " I O. 2 5 5.949 Z. 9.4 e 5 5O' I 3 3.45 – 5' I 4 I. 26'30 L | 16 || 25'949 26'o60 9°o 71°8 o' 52 3. 53°O I I. 3 I'43 The numerical value of the Sum of Equivalents in column II = Wire Interval + (sum of Micrometer-Readings = 50) x 16" 78o + sum of Level-Readings x o”oo646; where the Wile Interval for wire 15 is zero, and for wire 16 = 3, 18" Z8. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1896 the adopted Instrumental Constant was 2.21"'58. 2. Very faint ; hazy. Nov. 3od 2h. All wires found broken. AT THE ROYAL OBSERVATORY GREENWICH DURING THE YEARS 1886–1899. MERIDIAN ZENITH DISTANCEs of y DRACONIs observed with the REFLEX ZENITH TUBE-continued. ---------> à Micrometer Readings. Level Readings. Sum of Equiva- . Concluded # Day and Hour . --> lents for wire, Star’s - Mean ‘5 of +5 . . Tº : 5-; for Micrometer- observed Star Zenith º Observation, § 5 3 A. B. *: $. Readings and Zenith Distance Correction. , Distance 3 1897. § #E 2 div. div. 5 # for Level. North. North ź - . à } É : 7", 7" É Readings. 1897. % •. d H. 8 # / 4 & f & £4 Aſ f & # f I July I 3. Io B | R | 15 24'040 27"Ooo 297 5'3 O'74 O. 18.19 I. 28'92 — a • g - L | 16 || 24'O4o 25-673 8-3 || 639 o'47 3. I 3°47 I. 26:36 — 2-04 || I. 25.60 2. 14. Io | CD | R I 5 24'099 27°ooo 3O'O 849 O'74 O. 19:18 I. 27.93 – 2 33 I. 2 K-82 L | 16 || 24°o99 || 25'734 8’4 63-4 o'47 3. I 5°48 I. 28'37 • 2 5 3 15. Io RC R | I 5 24°o85 27 ooo 32 'O 86°o o'76 o. 1896 I. 28:15 •= 2 * , ſº a L | 16 || 24'085 25.810 8:o 63.0 o'46 3. I6'52 I. 29°4 I 2-62 I. 26-16 4. 16. 10 | H | R 15 24-os) 27-ooo 3 I ‘2 85'o o'75 o. I 9°o2 I. 28'09 — 2 "O I I. 2 S. "I L | 16 || 24'089 25-728 8:3 62°4 o'46 3. I 5’2 I I. 28' Io . 9 . 25"I Q 5 *7, 9 |AO | | || 4:45 5.3% tº $º º? | 3: 2.54 32.43 | – ; so | 1.247, R 15 25:620 25'309 28'3 84°o O'73 o. 16:32 I. 3O'79 9 e 6 || August 4. 9 | B | R | I 5 24'8oo 26°ooo 287 817 o'71 O. I4' I 3 I. 32 '98 – 7' I. 2 R " L | 16 24'8oo 25°393 || Io'7 639 o°48 || 3. 2 I-54 I. 34°43 7'77 | I. 25'94 7 27, 7 || S R | 15 24.618 26-ooo 31 ‘o 86°o o'76 O. II ‘I 3 I. 35'98 … * L | 16 || 24-618 25-730 I 2 "O 64'o o'49 || 3.24°14 I. 37°O3 — 1 1-89 I. 24.62 8 I O. 7 CD R I 5 23°456 27°ooo 25-6 84'o o'71 o. 8:36 1. 38°75 — I 2 °2 I. 2 5 4.8 L | 16 || 23.456 26'992 8:3 66-8 o'49 3. 25'82 1. 38-71 3'25 . 25'4 9 II. 6 | AC L | 16 || 23°456 26'932 9:4 67.9 o'50 3. 24-82 I. 37'71 – T 2 * e R | I 5 23: 560 26'932 26-2 848 o'72 o. 897 I. 38 I 4 I 3°29 I. 24'64 IO 2 I. 6 || B | R I 5 || 23'440 27°ooo 23° 5 81.9 o'68 o. 8. O6 I. 39'O5 I 3 '' I. 2 K. 28 - - L | 16 || 23'44o 27°ooo 9'5 68.3 o' 5o 3. 25'70 I. 38'59 — I 3’54. . 25 } 11 || October I6. 4 || JS | R. I 5 24'490 26°ooo 23.7 8 I-2 o°68 o. 8:90 1. 38'2 I tº e t L | 16 || 24'490 || 25'865 17'o 79°1 o'62 3. 24’39 1. 37:28 — I 2 of 1. 25.68 ! 12 3o. 3 | H | R 15 23-679 27-ooo 2 I ‘5 80.2 o-66 o. 12'o6 I. 35 “OS — o'8 I. 2 S. " - L | 16 || 23-679 26°584 || 12'o 70-8 o'54 || 3. 2278 I. 35-67 9'87 | I. 25'49 The numerical value of the Sum of Equivalents in column 11 = Wire Interval, + (sum of Micrometer-Readings – 5or) x 16" 78o + sum of Level-Readings x o”oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = 3". 17”82. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1897 the adopted Instrumental Constant was 1'.47”. 11. 22 MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCES of y. DRACONIS observed with the REFLEx ZENITH TUBE-continued. # Micrometer Readings. Level Readings. Sum of Equiva- Concluded # Day and Hour <- --> lents for wire, Star’s Mean *5 Of : . . . ; : for Micrometer- observed Star Zenith º Observation, g g É A. B. H. g. Readings and Zenith Distance | Correction. Distance 3 1898. # # sº div. div. #5 for Level- North. North % à & : ')". 7°. -: É Readings. 1898'o. h * / £ A / f A / A M 4 44 1 || May 2 I. I4 || B | R 15 27.861 24°ooo 24'4. 83.8 o'70 I. 5'49 I. I 3 '85 º e L | 16 || 27.861 2 I oz.6 8. I 67.5 O'49 3. 33' 19 I. I 3 '85 + 12'59 I. 26'44 2 June 2. I 3 || B | R I 5 25'774 25°ooo 2 I ‘5 80-9 o'66 O. 47°22 1. 16.83 + 87 I I. 26.7 I L | 16 || 25.774 22:513 I4-7 || 74°o o'58 3. 23-22 I. I9' 17 7 . 20.7 3 7. I 3 | S R I 5 247 Io 26-ooo 24'O 83'o o'69 o. 46.17 I. 17-88 º º L | 16 24.7 Io 23’5 I4. 8'O 69'o o'50 3. 22°09 I. I 8'04 + 7'ol I. 24°97 4. Io. 13 | W R 15 25-690 25'OOO 23 °o 82°5 o 68 O. 45'82 I. I 8:23 º e L | 16 25-690 22°598 I 2 "O 70'2 o' 53 3.23. I 8 I. I 9' I 3 + 5°99 I. 24.67 5 19. I 2 | W R 15 24' 504. 26-ooo 24 O 8oro o'67 o. 42'69 I. 2 I 36 e © L | 16 || 24' 504 || 23'923 I 2-8 69'2 O'53 3. 25'52 I. 2 I'47 + 3'O2 I - 24°44. 6 20. I2 | H R I 5 24'412 26-ooo 24'3 8O-2 O'68 O. 4 I 15 I. 22 '90 + 2-6 26°oo L | 16 24'412 24' I 49 12:9 | 68-9 o'53 3.2777 I. 23-72 9 te 7 22. I2 | B | R 15 26:006 24:358 23°4 || 799 || 0-67 O. 4O'34. I. 237 I + 2 to 3 25°75 L | 16 26°ooô 22:556 12-9 69'2 o' 53 3. 27.78 I. 23.73 º 8 || July 7. II | RC R 15 24; 148 26-ooo 27°o 83°o o'71 o. 36.75 I. 27:30 — 2-85 I. 23°43 L | 16 24; 148 24°507 I O' O 66"o o'49 3. 29°30 25°25 e 9 I4. Io | H | R. 15 25°oo2 2 5'Ooo 29°2 85'o O'74 O. 34’33 I. 29.72 - A * º I, 16 || 25°oo2 23:861 8'2 64'I O'47 3. 32°77 I. 28-72 4-97 I. 24'25 I O 16. Io RC R 15 25 odo 25-ooo 29-0 | 84°o o'73 O. 34°29 1. 2976 – 5:55 | 1. 24:28 L | 16 25 'ooo 23'933 9.8 65°o O'48 3. 33’95 I. 29-90 . 24 I I 22. Io | H | R 15 24.825 25°ooo 28' I 83.7 o'72 O. 3 I'34. I. 327 I – 7: º L I6 24'825 24'238 8'5 64'9 O'47 3. 36. I 3 I, 32°o8 7:23 I. 25°17 12 August Io. 8 RC R 15 24 585 25°ooo 27°o 84'o o'72 O. 27°31 I. 3674 – T T * . . . L | 16 || 24 585 24'760 8'2 65’7 o'48 3. 40-86 1. 36.81 II '8o I. 24'98 I 3 I 3. 8 || B | R | 15 24:631 25°ooo 3O'2 83.7 o'74. o. 28' I I I. 35'94, - T © " te L | 16 24.631 24-730 I O'O 63'o O'47 3. 4 I I 3 1. 37'08 12:37 I. 24.' I 4 I4 16. 8 CD R 15 24:577 25°ooo 29:6 82.3 o'72 O. 27° 19 1. 36.86 — I 2 ° I. 24." L | 16 24' 577 24'833 Io'9 64°o o'49 3. 4 I '97 I. 37'92 2'94 I. 24'45 { I 5 I7. 8 B | R 15 24' 530 25°ooo 28.6 82°o o'72 O. 26' 39 1. 37.66 — I 3° I 3 I. 24'60 L | 16 24' 53o 24'870 7.8 74-6 o'53 3. 4 I '84 I. 37.79 I6 24. 8 RC R 15 24°360 25°ooo 33°o 87.2 o'78 o. 23.60 I. 4O'45 — I4'21 I. 2 5'74 L | 16 24°360 25° I 45 6.2 61 °o o'43 3. 43’50 I. 39'45 17 September 16. 6 | H | R 15 24:28o 25-ooo 35-6 | 89° 1 || O'81 O. 22:29 1. 4I /6 — 16:23 I. 25 17 L | 16 2428O 25°322 3'9 57'3 O'39 3. 45 ‘O9 I. 4 I ‘O4. I 8 26. 6 B | R 15 24-329 25"Ooo 33' 3 91'o o'80 O. 23' I O I. 4O'95 — 16°31 I. 24°37 L | 16 || 24-329 25°234 2 °2 6o'o O'40 3. 44'45 I. 4O'4O The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings - 48) × 16" 780 + sum of Level-Readings x o"'ooé46; where the Wire Interval for wire 15 is zero, and for wire 16 = 3.17”82. The numerical difference, between this slim of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1898 the adopted Instrumental Constant was 2',4"oş (but for May 21, 2', 19":34). 2. Very diffused. AT THE ROYAL OBSERVATORY, GREENWICH, DURING THE YEARS 1886-1899. 23 MERIDIAN ZENITH DISTANCES of y DRACONIs observed with the REFLEx ZENITH TUBE-continued. § Micrometer Readings. Level Readings. Sum of Equiva- Concluded # Day and Hour tº --> lents for wire, Star's Mean *: of : . . Tº -- 5.3 for Micrometer- observed Star Zenith £d Observation, § g 3 A. B. º; ; Readings and Zenith Distance | Correction. Distance § 1898. § # § div. div. # º for Level- North. North c; - à # : 7". 7". ã3 Readings. 1898 ‘o. 2: Cº- d h // 4. */ f & M. # / f * / I | October 3. 5 W R 15 24'328 25°ooo 34°o 92°4 o'81 O. 23°og 1. 40.96 I6'ol I. 24.8 6 24' 328 2 K-2 56 I • º O' º I. A.O." º- . 24'84. L | I 4’3 5' 25 4 59'4 39 3. 44°79 4O'74. 2 2O. 4 || B | R. 15 24:420 25°ooo 26'5 85.3 o'72 O. 24' 55 I. 39'50 – I A " º L | 16 || 24'420 25 o81 7. I 66-2 o'47 3.43°48 I. 39'43 I 4’39 I. 25'08 3 28. 4 || B | R. I 5 24°52′o 25°ooo 25°o 83’5 o'70 o. 26'2 I I. 37.84 – I 2 * I I I. 24." R2 - L | 16 24°52′o 24'860 8-9 67°o o'49 3. 41'46 I. 37°4 I 3 • 24' 5 4. 31. 3 || W R I 5 24' 5 I4. 25'OOO. 25'4. 82°o o'69 o. 26' Io I. 37'95 - I 2 " ... I I. 25 '26 L | 16 || 24°514 24,888 9'4. 66-2 o°49 3. 4I '83 1. 37-78 5 . 25°3 5 | November I. 3 || B | R 15 24' 560 25'OOO 23'4. 83.6 o'69 o, 26-87 1. 37:18 - I 2 ° 2 I I. 24." L 16 24' 560 24-766 8.8 68.8 o'50 3. 4o'57 I. 36'52 3 . 24'54 6 8. 3 || W R | 15 24'630 25-ooo 24-2 | 84°o o'70 o. 28'05 1. 36°oo -io's I, 2 N. "I L | 16 24-630 24'664 9°o 69'o o' 50 3. 4-o'O4. I. 35'99 7 . 25 I 3 7 Io. 3 || W R 5 24'694 25°ooo 23 °o 83'o o:69 o. 29' 12 I. 34°93 = I (Y" e L | 16 || 24-694 24' 586 I I*O 7o'o o' 52 3. 39'82 I. 35'77 Io'39 I. 24-96 8 22. 2 | W R I 5 24.842 25°ooo I9'5 81: 5 o'65 o. 3 I 55 I. 32°50 - "7" - L | 16 || 24.842 24, 182 I I*O 72°2 O'54 3. 35° 55 I. 3 I 50 7'3 I I. 24. 69 9 || December 22, 23 W R I 5 25'446 25-ooo 15.8 80°o o°62 o. 41'66 * **, 39 || -- 2:66 I. 2 N. "I L | 16 || 25'446 2 3'O43 I 3 '4. 762 o'58 3. 26'60 I. 22' 55 . 25' I 3 I O 29. 23 W R 15 26:604 24'OOO 17°o 75°o o'59 o. 44'29 1. 1976 º º L | 16 || 26-604 || 2 I-744 | 1.4°o 76.5 || O'58 || 3. 24'23 . .343 | + 5°97 | 1. 25'04 The numerical value of the Sum of Equivalents in column 11 = Wire Interval + (sum of Micrometer-Readings – 481) x 16"'78o + sum of Level-Readings x o”oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = 3’. 17”82. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1898 the adopted Instrumental Constant was 2'.4"'o'; (but for May 21, 2', 19”34). 2. Cloudy. 24 MERIDIAN ZENITH DISTANCES OF y DRACONIS WITH THE REFLEx ZENITH TUBE, MERIDIAN ZENITH DISTANCEs of y DRACONIS observed with the REFLEx ZENITH TUBE-continued. à Micrometer Readings. Level Readings. Sum of Equiva- cºnclude: § Day and Hour ---> lents for wire, Star’s Mean ‘; of *t e ". | 5– for Micrometer- observed Star Zenith º Observation, g 5 # A. B. 'g : Readings and Zenith Distance | Correction. Distance 3 1899. ; # g div div, ‘E H for Level- North. North à 5 || 3 | = 7 7°. ää Readings. 1899'o. h - 6 A / Z # / * A / # / w f / I January 2. 23 W R 15 25-652 25°ooo I O ‘O 79.2 o'61 O. 45° II I. I 8:8 I e o L | 16 25-652 22°574 13.8 762 o' 58 3. 22°2O I. I 8:28 + 5°89 I. 24'44 2. Io. 23 || W R 15 25'852 25'OOO I 3'5 74.8 o'57 - o. 48°42 I. I 5'59 e º L | 16 25.852 22-181 | 18.7 | 802 o'64 3. I 9°o I I. I 5°og + 8:53 I. 23.83 3 25. 22 || W R 15 26. Io9 25°ooo I 2 "O 75’7 o' 57 O. 52 '74. I. I I I 8 º wº L | 16 || 26' 109 2 I '8o I I6'o 79.2 o'62 3. I6'93 I. I 3 'O I + 1 3'22 I. 25°32 4. 26. I | W R | 15 26-068 25°ooo I4'O 77°4 O'59 o. 52-07 I. I I-85 e e L | 16 26-068 2 I '784 I5'4. 79°o o'61 . I 5'95 I. I 2 “O2 + 1 3’51 I. 25°45 5 27. 21 | W R | 15 26: I I I 25'OOO I4'O 78.2 o'59 . 52'8o I. I I "I 2 º s - L | 16 || 26: I I I 2 I-690 I4-9 78.2 o'60 . I 5 'o'7 I. I I I 5 + I 3 '80 . 24'94. 6 | February 20, 20 | B | R. 15 26-402 25°ooo 1 4-8 76°4 o'59 o. 57.67 I. 6:25 e e L | 16 || 26:402 20:987 16-5 78.1 o’61 8-17 4'25 + 19:26 . 24°5 I 7 || March 4. 19 | B | R. I 5 26-554 25°ooo I 5"9" | 79°o o°61 o:25 I. 3-67 e o L | 16 26-554 20:873 13-6 || 76.8 o'58 878 1. 4.86 +20:70 I. 2497 8 May 6. 15 W R | 15 26-151 25"Ooo 25°o 85'4 O'71 - 53'59 I. IO-33 e e L | 16 || 26-151 2 I 590 7-8 68.2 o°49 3. I 3-96 I. Io'O4. + I4°o I I. 24'2 O The numerical value of the Sum of Equivalents in column 1 I = Wire Interval + (sum of Micrometer-Readings – 48*) x 16”78o + sum of Level-Readings x o”“oo646; where the Wire Interval for wire 15 is zero, and for wire 16 = 3'. 17”82. The numerical difference between this sum of Equivalents and the Instrumental Constant is the star's Z. D. North. During the year 1899 the adopted Instrumental Constant was 2'.3"'92. 3. Unsteady. GREENYAVI (CIH [. wº MERIDIAN ZENITH DISTANCES of ). DRACONIs witH THE REFLEx ZENITH TUBE, 1886 TO 1899.