in SPHERICAL BODIES- 367 
18. Hencs, by reafoning as in § 6. the momentary incre- 
ment of the temperature, or fenfible heat, of any ftratum, is as 
es directly, and its capacity for heat, or m b inverfely, 
Tipe a 
ais Oar ae x b 
2 mre 
ax a 
ee a and 
3mx  3mr 
LET = =y, then — re = 7, fo that — 
2 
a by a J 
therefore = ae ¥,°:. Hence @.= C-- 3mrLogb Bi oe 
a = 
C3, 3mrLogb ss 
19. To determine C, if T be the temperature of the air at 
2 
ab 
the furface, when r=7, T = C+ 3m Loge? dnd» C= 
a b 
ae 3mrLogb 
ne ab a b : 
Hesce: bt 2 3mr Log b ui 3mrLogb — 
a (b—b7) 
eye 3mrLogd 
Tuis formula, when x =7 gives 5=T, and when »# is in- 
tee *(b— 5 : 
finite, it gives k= T— mr In all intermediate 
cafes, 
