248 TRANSACTIONS OF THE 
Equation (1) becomes on substitution of these values 
T—110-1.4L-.002h-+ (.9L-12) cos t+-9 cos © (5) 
which holds for the eastern division and 
T—121-1.4L-.0033h-+-23 cos t+11 cos ©+3 cos ® cost (6) 
for the arid west. 
The equations assume that the annual and daily 
march of temperature are cosine functions, and that the 
mean annual temperature and the annual range ‘are linear 
functions of the latitude and elevation. The facts justify 
these assumptions. The mean evror in using equation (1) 
was +214 deg. F. and in using equations (5) and (6) 
+314 deg. F. 
