RADIATION IN ABSOLUTE MEASURE AT VERY LOW TEMPERATURES. 365 
and t 2 ; to divide these columns similarly, then to take the sums of the numbers in each 
of the equal parts, and to use the respective sums as the values of??, t, and t 2 , to form 
three equations. If this is done the equations become the following, as will be seen 
from the sums indicated in the specimen page, the coefficients of a being 10, as there 
are ten numbers in each of the three sums. 
10a + 45/3+ 285y = 220, 
10a+145/3 +218 5y = 542, 
10a + 245/3 +G085y = 454. 
Solving these simultaneous equations, we find for the values of the three unknown 
quantities, 
a = -4-175 ; /3 = 7'115 ; y = -0'205. 
33. Having determined the values of a, /3, and y, the next process is to find the 
series of values of n', which is done by putting the numerical values of t into the 
equation n' — a + /3 t + yt 2 . The number n' is not required for the calculation of e, but 
is needed for comparison with n, and for verification of the exactness of the process. 
The values of fit and yt 2 are most easily obtained by means of Crelle’s Multiplication 
n = a + /3t + yt 2 + 8t 3 . 
Silvered globe in vacuum = O'06 M. April 2, 1906. 
[In this diagram and the next one the small dots representing n have not come out, as they lie on the curve.] 
