580 
DR. ANDREWS ON THE CONTINUITY OE THE 
correction was always applied, as was also a trifling correction of 7 millims. for a differ- 
ence of capillary depression in the two tubes. 
In order to show more clearly the methods of reduction, I will give the details of one 
experiment. 
Volume of air at 0° and 760 millims. calculated from the observations when the air 
was expanded to a e, 0-3124 cub. centim. 
Volume of same air calculated from the observations when the air was expanded to 
ad, 0-3122 cub. centim. 
Mean volume of air at 0° and 760 millims., 0'3123 cub. centim. 
The volumes of the carbonic acid, deduced in like manner from two independent 
observations, were 0-3096 cub. centim. and 0-3094 cub. centim. Mean 0-3095 cub. 
centim. 
The length of the column of air after compression, at 10°-76, in the capillary air-tube 
was 272-9 millims., corresponding to 0-006757 cub. centim. Hence we have 
v_ Q-006757 L_ 
6 — 0-3123 x 1*0394 ~48-04‘ 
But as the difference in the heights of the mercurial columns in the air-tube and car- 
bonic-acid-tube, after allowing for the difference of capillary depression, was 178 millims., 
this result requires a further correction of an atmosphere), in order to render it 
comparable with the compression in the carbonic-acid-tube. The final value for c>, the 
fraction representing the ratio of the volume of the compressed air at the temperature 
of the experiment to its volume at the same temperature and under the pressure of one 
atmosphere, will be 
S = ifST 
The corresponding length of the carbonic acid at 13°-22, in its capillary tube, was 124-6 
millims., equivalent to 0-004211 cub. centim., from which we deduce for the corre- 
sponding fraction for the carbonic acid 
0-004211 1 
£ — 0-3095 x l-0489~77-09’ 
Hence it follows that the same pressure, which reduced a given volume of air at 10°-76 
to 4 - 7 1 8 1 of its volume at the same temperature under one atmosphere, reduced carbonic 
acid at 13°‘22 to 7 - ? V ^ of its volume at the temperature of 13°-22, and under a pressure 
of one atmosphere. Or assuming the compression of the air to be approximately a 
measure of the pressure, we may state that under a pressure of about 47*8 atmospheres 
carbonic acid at 13°-22 contracts to 7 - 7 f Q9 of its volume under one atmosphere. 
In the following Tables, S is the fraction representing the ratio of the volumes of the 
air after and before compression to one another, s the corresponding fraction for the 
carbonic acid, t and the temperatures of the air and carbonic acid respectively, l the 
number of volumes which 17,000 volumes of carbonic acid, measured at 0° and 760 
