368 



HENRY A. ROWLAND 



between and 100, and say 10 and -f 10. This difference I at 

 first determined from Regnault's tables, but afterwards made a deter- 

 mination of it, and have applied the correction. 11 



The table given by Regnault is for one specimen of glass only; and 

 I sought to better it by taking the expansion at 100 from the mean 

 of the five specimens given by Regnault on p. 231 of the first volume 

 of his Relation des Experiences, and reducing the numbers on page 237 

 in the same proportion. I thus found the values given in the second 

 column of the following table. 



TABLE VIII. COEFFICIENT OF EXPANSION OF THE GLASS OF THE AIR THER- 

 MOMETER, ACCORDING TO THE AIR THERMOMETER. 



The second column contains the values which I have used, and one 

 of the last three columns contains my experimental results, the last 

 being probably the best. The errors by the use of the second column 

 compared with the last are as follows: 



TT i inr from using & 100 6 40 = -0000008 instead of -0000011; 

 TD 3 r j r from using & 100 = -0000264 instead of -0000287; 



or, ^Vrr for both together. 



As the error is so small, I have not thought it worth while to entirely 

 recalculate the tables, but have calculated a table of corrections (see 

 opposite page), and have so corrected them. 



11 This was determined by means of a large weight thermometer in which the mer- 

 cury had been carefully boiled. The glass was from the same tube as that of the air 

 thermometer, and they were cut from it within a few inches of each other. 



12 Relations des Experiences, i, 328. 

 13 Fogg. Ann., cxiii, 135. 

 "Experimental Physik, Wiillner, i, 67. 



