LONGITUDE FROM ZENITH DISTANCES OF THE MOON. 



25 



Observer, Nichol. tl 



1874, Oct. 29, Procyon o - 3 



Nov. 1 5, 8 Capricorn! .... 3'i 



1 6, Fomalhaut + 1*4 



22, a, Arietis + o - 3 



23, a Tauri 



27, y Leonis . 



28, ft Ursae . . 



29, a Leonis . 

 29, a Leonis . 



Dec. 14, ft Ceti . . . 

 i5, ft Ceti . . . 

 1 8, a Arietis. 



o'o 



0-8 



i -o 



3-o 



2'2 



+07 

 +07 

 - 0-6 



Observer, Tupman, 



1874, Oct. 26, a Tauri 



26, a Tauri 



26, Procyon 



1875, Jan. 20, ft Gemiuorum. 



20, (3 Geminorum 



20, ft Geminorum. 



2 1 , a. Leonis 

 21,0. Leonis 



22, ft Leonis 



22, ft Leonis .... 



+ 2-0 



O'O 



4- 0-4 

 + o-5 

 + o-3 

 ro 

 o-3 

 o-i 



- 2-3 



- 3-3 



+ 

 4 



19, a Tauri ........ + o'4 



21, y Geminorum 

 26, 8 Leonis 

 3o, a Yirginis 



r3 



i -8 



o - 5 



3i, a 2 Libras ...... + r 



1876, Jan. i, a 2 Librae 



1 3, ft Arietis , 



14, ft Arietis 



1 6, a Tauri ....... 4- i -3 



1 8, y Geminorum . 

 19, ft Geminorum . 

 19, ft Geminorum. . 

 19, ft Geminorum. . 



23, 8 Leonis 



24, ft Leonis 



25, a Virginia 



27, a. Virginia ...... + 3'2 



27, a Virginia ..... 2 - o 



The means of the above numbers 



2*9 

 + 3'i 

 4- 1-4 



n 



ro 



2'5 



o - 3 



are, for Mr. Nichol o % i o 

 for Capt. Tupman o'23 



These quantities show that a very small systematic error is introduced 

 by using the time found by the transit instrument. 



65. The whole of the vertical transits of the Moon and of stars are given 

 in Table IX. 



Column 4 is the mean of the clock times of transit over the five horizontal 

 wires. No imperfect transits were observed. No correction is ever required 

 for inequality of motion in z. d. The local sidereal time of observation 

 (subject to a small constant correction of + O s -07) is obtained by applying 

 to the time in column 4 the proper clock correction taken from Table VI. 



Column 6 contains the reading of the vertical circle, as obtained always 

 from the mean of the four microscope-micrometers corrected for runs. 



Column 7 is the level indication, always additive, and is the sum of the four 

 level readings divided by 2, the divisions on the levels being of the value of 2". 



Column 8 contains the readings of the mercurial barometer suspended in 



