730 REPORT— 1896. 
From a considerable number of photographs of Jupiter, four of the best, taken 
on the following dates, were selected for measurement:— 
1895, February 24, region &’—D, orthochromatic plate. 
1895, March 21, ,,° O—D, rr 
1896, April 22, ,, G—F, ordinary plate. 
1896, May Go, 1G= 5; + on 
The following table contains the data, taken in part from Marth’s ephemeris, 
which are required for the reduction of the photographs :— 
3? 
| Date of Photograph a B Eq. Diam. p | 
| DH ° ' ’ 5 ie ' w" m. 
1895, Febrnary 24 8 TO 22 2 05 41-09 0°654 
| 4, March ~ 21 82 11 05 2 01 37°91 0-263 
1896; April 228. .| 10 53. 0 34 38-00 0:4286 
» May GiBi ce es kn 40:4 $88 0 32 36-48 0-4114 
mm. 
Focal length of telescope for )= 4640. 
” ” rr Hy= 4653. 
L=velocity oflightin kilometres = 299860). 
ReEsvLts. 
Photograph of February 24, 1895. Photograph of April 22, 1896. 
A D tang Vkm. A D tan p V km. 
5230 23°65 0326 10°37 4352 11°30 ‘O744 12°53 
5270 24:75 “0470 15 54 4415 12°35 0644 11°68 
5328 26°20 “0404 14°11 A427 12°70 0626 11°64 
5372 27:25 “0434 15°50 4476 13°80 “0614 12°28 
5430 28°75 0434 LN SEA U7) 4495 14:40 0660 13°42 
5456 19:40 0296 11:22 4529 14°75 0490 1035 
Mean 13°82 Mean 11:98 
Photograph of March 21, 1895. Photograph of May 6, 1896, 
5230 23°65 "0656 19°14 4315 10°60 0816 12°47 
5270 24°75 0464 14:06 4370 11°65 0846 14:03 
5328 26°20 0484 15°50 4427 12:70 ‘0774 13°81 
5372 27:25 0390 12°77 4476 13°80 0590 11°32 
5430 28°75 0460 15:72 4495 14:10 “0594 11:59 
5456 29°40 .0390 13°56 4529 14°75 0544 11:02 
Mean 15:12 Mean 12°37 
Giving double weight to the last two photographs, for which the dispersion is 
about twice that of the first two, the result of all the measures is 
km. km. 
V=12-94 +027. 
Deslandres found V =12°5, 11:9, 12°1, 11:7. Bélopolsky found V = 11°42. 
The computed value is 12:1 to 12°8, according to the value of the equatorial 
diameter of Jupiter which is assumed. 
Bélopolsky has pointed out that his spectroscopic observations of both Jupiter 
and Saturn give a smaller velocity than that deduced from observations of spots, 
and he suggests, in explanation of this fact, that Jupiter may be a body like that 
considered in Schmidt’s theory of the sun, so that rays apparently proceeding 
