352 
PROFESSOR GRAHAM ON THE MOTION OF GASES. 
Table I. — Transpiration by Capillary H 237*875 inches in length, and inch 
in diameter. 
Gas transpired. 
Experi- 
ment I. 
Experi- 
ment II. 
Mean. 
Air=l. 
Oxygen =1. 
Observations. 
Oxygen 
Air 
Hydrogen 
Protocarb. hydrogen (CH^). 
Carbonic oxide 
1146 
1032 
509 
631 
994 
1147 
1032 
510 
630 
995 
1146*5 
1032* 
509*5 
630*5 
994*5 
1*0000 
1*0000 
0*9001 
0*4443 
0*5499 
0*8674 
Bar. 29 * 696 . Temp. 67° Fahr. 
Air 
Carbonic acid 
798 
668 
799 
668 
798*5 
668* 
0*8366 
0*7529 
Bar. 29 * 602 . Temp. 69° Fahr. 
I produce these results principally to show how small the variation is in carefully 
made experiments, not amounting to more than 1 second in times which exceed 1000 
seconds for two of the gases, as well as to afford standard numbers to compare with 
those obtained for reduced lengths of the same tube. 
Table II. — Transpiration times of equal volumes by Capillary H of different 
lengths. 
Length of capillary. 
Oxygen. 
Air. 
Carbonic 
oxide. 
Carbonic 
acid. 
Protocarburetted 
hydrogen. 
Hydrogen. 
237*875 inches= 1*0000 
1 
0*9001 
0*8674 
0*7529 
0*5499 
0*4443 
0*8539 
1 
0*8983 
0*4422 
0*6521 
1 
0*9009 
0*8681 
0*7585 
0*5506 
0*4434 
0*4513 
1 
0*9013 
0*8743 
0*7900 
0*5636 
0*4424 
0*3195 
1 
0*9131 
0*8793 
0*8501 
0*5826 
0*4041 
0*2149 
1 
0*9149 
0*8799 
0*8849 
0*6049 
0*3842 
0*1234 
1 
0*9131 
0*8790 
0*8802 
0*5860 
0*3924 
18*125 inches = 0*0762 
1 
0*9138 
0*8879 
1*0395 
0*5948 
0*3879 
The absolute times of transpiration varied with air from 1032 seconds for the 
greatest to 116 seconds for the shortest length of the capillary. 
It will be remarked that the transpiration times of air and hydrogen are preserved 
with the greatest uniformity, while the length of the capillary is reduced from 1 to 
0*4513, air varying only from 0*9001 to 0*9013, and hydrogen from 0*4443 to 0*4424. 
The variation of the rate of carbonic oxide is more sensible although still small, 
namely, from 0*8674 to 0*8743. Protocarburetted hydrogen, however, rises for the 
same change in the tube from 0*5499 to 0*5636, and carbonic acid still more con- 
siderably, namely, from 0*7529 to 0*7900. The resistance of the tube is insufficient 
for shorter lengths, the influence of effusion becoming manifest, and most conspicu- 
ously so in carbonic acid. The times of effusion of equal volumes, to which the gases 
are now converging, although with unequal degrees of rapidity, are, for oxygen 1, 
air 0*9507, carbonic oxide 0*9356, carbonic acid 1*1760, protocarburetted hydrogen 
0 * 7071 , and hydrogen 0*2502. 
