82 
Hence D= -Jdb, and 
(1 - BaWy = a A (b .k) + b A ( a.k ) 
taking the upper or lower sign throughout. 
r_*_ = + =T [ C 
J A (x.k) J A (y.k) J 
dx 
A (x.k) J A (y.h) ' J A {cc.k) 
o b b 
and ultimately 
f a dx , dx _ r 
J A(x.k)~J A{x.k) J 
dx 
A (cc.k) 
A {x.k) 
ooo 
aA(ii)fiA(ai) 
wneie c- i_ kw 
according as the upper or lower sign is taken. 
“Observations made in St. Moritz* in the Winter 1882-3,” 
by Arthur Wm. Waters, F.G.S., F.L.S. 
Knowing that the session of the Society will soon close I 
hasten to put together a few of my winter observations in 
order that they may be read at the closing Meeting. 
Much of my time has been occupied in preparing new 
instruments adapted for the climate, and therefore my 
observations are few and imperfect, but I have tried to 
obtain a few figures bearing upon the question of the 
influence of a snow covering upon climate. This can only 
be worked out after many years’ observations, but I hope that 
some of the points noticed will afterwards be of considerable 
use, and perhaps the most interesting are those on the tem- 
perature indicated by a thermometer placed in the snow. 
The thermometer used was a common one painted white 
over the bulb, and which I carefully tested for the freezing 
point, but some of the lower degrees may not be absolutely 
correct. It was placed vertically with the bulb about 25 
centimetres below the surface and with the upper part one 
or two inches below the surface; and there will all through 
the winter have been at least half a metre of snow between 
the bulb and the earth. 
# St. Moritz, the highest village in the Engadine, is 6089 feet above 
the sea. 
