OF HEAT FROM THE MOON. 
625 
will rise more rapidly towards full moon than the total heat-curve, and should therefore 
diverge less from Zollner’s than the total lieat-curve, when the ordinates are increased 
by a suitable factor. 
This comparison has accordingly been made. The ordinates of the curve B (Plate 
XLVIII.) have been multiplied by 5*7916; to make the curve correspond in average 
height with curve A (Plate XLVIII.) ; and, with the same object, Zollner’s photometric 
determinations obtained with two different photometers and those by Sir John PIerschel 
with the prism photometer -were multiplied respectively by the following factors"*: — 
Zollner’s 1st method 3-8471 
„ 2nd (or improved) method .... 3-8304 
Herschel’s 4-2920 
Applying these factors to the numbers given at page 102 of the ‘ Photometrische 
Untersuchungen’ (for Zollner’s observations), and to the quantities taken from plate iv. 
of that work for Herschel’s results, the following numbers were obtained : — 
Professor Zollner; 1st method. 
e. 
Moon’s light. 
£. 
Moon’s light. 
1 
Oo 
181-2 
+ 13 
317-7 
-28 
217-1 
+ 27 
222-7 
- 8 
354-7 
+ 42 
146-7 
- 1 
379-3 
+ 69 
56-1 
+ 5 
335-5 
Professor Zollner ; 2nd method. 
S. 
Moon’s light. 
£. 
Moon’s light. 
I 
-r 
Oo 
77-8 
0 
-19 
262-0 . 
-58 
103-9 
-11 
339-9 
-46 
138-3 
+ 28 
218-3 
-41 
168-2 
+ 39 
159-7 
-33 
187-1; 
+ 52 
111-5 
-27 
243-1' 
+ 62 
78-1 
-24 
273-4 
* The necessity for 
applying different factors to render comparable groups 
of observations already similarly 
treated by Zollner, arises from the fact that Zollner, 
since he constructed his diagram, has added four obser- 
vations by his second method, and has discovered two errors of 10° each in the elongation of the moon as given 
in the ‘ Cape Observations.’ 
