ON THE LIGHT OF THE MOON AND OF THE PLANET JUPITER. 951 
h m : : o A ft. 
7 56 Sidereal time. — Venus.  —— d d = 50.6 
8 23 “ e | d = 61.1 
8 5. 279 Jupiter. | : d" = 93.6 
gg er “ : d" == 93.4 
819^. = z “ Perfectly clear." d" = 94.9 
March 27th. Perfectly clear. 
h m ft. 
9 2 Sid. time. Moon 54 days old. Diaphragm Z. a@ == ¢ 514 
9-6 " : s y d = 5.65 
pes = “ « « d= 5.68 
9 10 ia ee Diaphragm X. ge 1210 
pe See A p M uo M d — 11.00 
919 Wa s e SC | d = 12.10 
Lamp without diaphragm. Average e 
e D & VR 
m aca from wick 17.50, to apex 1.75. PTS 
To reduce the comparisons made with X to the standard aperture Z, the ratio 
Light from Z ` 1 
Light from X 4.63’ 
à as determined by experiment, is to be used. 
1860, March 29th. Clear. 
ER, Kë ft. 
9 00 - Sid. time. Moon, first quarter. Diaphragm X. d — 544 
« «o s « E « d = 5.77 
« m « « « d — 582 
S D ú ú | Full flame without diaphragm. d == 65.6 
Mean height from wick 1'”.68, to extreme apex 2^.10. d = 63.1 
The hour was not noted, but it was nearly as stated. : 
March 30th. “A red haze in the sky, which does not appear to obstruct the light 
much." * 
h ; CTS 
10 14 Sid. time. Moon 84 days old. . Diaphragm X. d = 5.95 
“ Di [11 [11 e d = 6.50 
“ E Di Di o Di d — 6.48 
"There was no glass screen before the lamp disc, and to reduce the observations to the 
usual standard, the lamp-light must be multiplied by the coefficient y = $, as well as 
by the ratio of Z to X, given under the date of March 27th. 
- * It appears, from the reductions, that the effect of the haze was more considerable than was at first sup- 
posed. 
