Pressure and Temperature Results for the Great Plateau. 2051 
6. For the monthly mean temperature at Kimberley— 
a = 64°5 — 13-365 sin (283° 15’ + 2) 
+ 1-626 sin (318° 13’ + 2¢) 
— 0-271 sin (42° 30’ + 3¢) 
— 0-159 sin (24° 48" + 44) +... 
7. For the monthly minimum temperature at Kimberley— 
a = 49°8 — 12-162 sin (272° 6’ + 2) 
+ 1-724 sin (318° 54’ + 2t) 
— 0-247 sin (61° 14-6’ + 32) 
— 0:148 sin (347° 0-3’ + 44) +. . 
8. For the monthly mean pressure at Kimberley— 
a@ = 26-055 inches + 0-1182 sin (285° 26-5’ + 2) 
— 0:0070 sin (330° + 2t) 
+ 0:0087 sin (275° 29:4’ + 32) 
— 0-0052 sin (348° 18 + 4#) +... 
Although Lambert’s and Bessel’s formule represent the facts of 
observation with remarkable accuracy, the simple sine curve, be- 
cause it is less cumbersome, is advantageous when, searching for 
analogies, we wish to roughly compare different curves together, 
say, for example, the temperatures of Durban with those of Kimberley. 
Neither, however, has any actual physical basis, or involves the 
effecting agencies any more than p, q, and a, in Lambert’s equation, 
applied to the path described by an inebriate would have anything to 
do with pints and quarts or the price of alcohol. The variable in 
each case, 2, or 7/7, or t, depends upon the sun’s Right Ascension. 
The seasons depend almost entirely upon the sun’s Declination. 
Right Ascension and Declination, it is true, vary together, but in 
such a totally different manner that the changes of temperature have 
no proportion to the sun’s angular velocity. In fact, of the two only 
the Declination needs to appear in any physical formula dealing 
with the supply of heat received from the sun. This, manifestly, 
does not imply that such a formula is easy to discover. Indeed it is 
not; the diversity of condition prevailing over the earth’s surface: 
land and water, garden and desert, acting and reacting upon the 
heat received ; weather not being made where it is used; and so 
forth—all help to order it otherwise. Thus we are, in general, 
content to accept the purely mathematical equation to a curve 
drawn on paper in the place of a formula based upon natural 
phenomena. — 
