3G6 
DR. J. T. BOTTOMLEY AND MR. F. A. KING ON THERMAL 
Tables. When calculated they are placed in suitable columns not shown in the 
specimen table, and from these columns the successive values of n' are obtained by 
addition, and they are placed in Column 8 ; while Column 9 gives the comparison 
between n and n'. Remembering that n—n' has to be multiplied by 10~ 4 , it will be 
seen that the process of averaging leaves nothing to be desired. 
34. An interesting experimental way of looking at this last question is to plot the 
values of n and n' on squared paper and to compare the curves. The results are 
shown in the accompanying diagrams, pp. 362, 365, 366 ; and the closeness of the 
Sooted globe cooling in vacuum. September 18, 1906. 
agreement between the smooth and the unsmoothed curves is shown to the eye to 
be quite satisfactory. If it were not, the necessity for revision of the work would at 
once be revealed. In' every case the plotted form of n and n' has been found to be 
obviously parabolic. 
35. Column 10 contains the “ time correction,” as defined above. The numbers in 
this column are added to the emissivity at t — 0 , which is the number that heads 
Column 11 , and the sums thus obtained give the emissivities at times t = 1 , t = 2 , 
&c., &c. These emissivities are placed in Column 11 ; and opposite to them, in 
Column 12 , the differences of temperatures between cooling body and surroundings 
at those times are shown ; while, in Column 13, the corresponding absolute tempera¬ 
tures of the cooling globe are given. 
