130 



Mr. W. Sutherland on the 



In order to compare the equation with the results of An- 

 drews's experiments as well as with those of Amagat, I have 

 converted Andrews's pressures (which are given in air- 

 manometer atmospheres, i. e. which are calculated from the 

 indications of an air-manometer on the assumption that air 

 obeys the Boyle-Mariotte law) into pressures in metres of 

 mercury, by means of the data for air at 16°, published by 

 Amagat (Comptes Rendu s, xcix. 1884). The temperature of 

 the air-manometer varied in Andrews's experiments : thus, 

 in the 35°*5 series it was about 16°, in the 64° series it was 9°, 

 and in the 100° series about 6° ; but I have assumed it in all 

 cases to be 16°. To convert Andrews's pressures, which are 

 greater than 65 metres of mercury, the greatest in Amagat's 

 air-determinations, I have had to use Amagat's determinations 

 for nitrogen at 17°*7* with such a correction as the difference 

 in the behaviour of air and nitrogen at lower pressures sug- 

 gests. In order to compare Amagat's results with those of 

 Andrews at the temperatures of 35°*5 C, 64°, and 100°, we 

 must regard his series at 35 c, l as taken at 35°'5, and we must 

 interpolate for the 64° series from his series for 60° and 70°. 

 This I have done for the construction of the subjoined table, 

 in which the top row of figures contains the volumes to which 

 unit volume at 0° and 760 millim. is reduced, and the suc- 

 cessive rows contain the corresponding pressures in metres 

 of mercury as given by Andrews, by Amagat, and by the 

 equation. 







co 2 



at 100° C. 











Volume 



•07628 



•04158 



•02712 



01422 



•00625 



•00359 



•00293 



•00264 





Pressure, Andrews ... 



„ Amagat 



„ equation . . . 



1315 

 1318 



23-33 

 23-42 



34-36 

 34-30 

 34-44 



59 77 

 59-20 

 60-00 



11053 

 109-40 

 109-63 



178-0 

 175-0 

 176-7 



236-5 

 241-6 



303-0 



301-5 



C0 2 at64°C. 



Volume 



06671 



•03560 



•02 64 



•01083 



•00377 



•00277 



•00235 



•00226 





Pressure, Andrews ... 



,, Amagat 



„ equation ... 



1328 

 13-34 



23-58 

 23-78 



34-79 

 34 80 

 3507 



60-40 

 60-20 

 60-22 



110-6 

 108-0 

 103 



178-0 

 1640 

 169-6 



2720 



278-5 



3200 

 318-8 



* Ann. de Chim. et de Phys. 5 ser. vol. xxii. 



