OF GASES AT HIGH EXHAUSTIONS. 
401 
654. Table I.—Log. dec.* of dry air at pressures between 760 millims. and 0'76 millim. 
Temp. 1 5° C. 
Pressure. 
Log. 
Pressure. 
Time of one complete vibration. 
Millims. 
decrement. 
Millims. 
Seconds. 
760 
0T124 
772 
11-20 
755 
0-1123 
633 
11-10 
750 
0-1121 
534 
11-05 
730 
0-1117 
425 
11-05 
702 
0-1110 
336 
10-96 
685 
0-1105 
260 
10-88 
664 
0-1100 
155 
10-90 
645 
0-1096 
106 
10-80 
627 
0-1091 
74 
10-80 
605 
0-1086 
50 
10-80 
587 
0-1082 
23 
10-72 
572 
0-1078 
8 
10-76 
550 
0-1073 
1 
10-70 
511 
0-1065 
0-68 
10-76 
495 
0-1062 
475 
0-1057 
M. 
440 
0-1050 
235-0 
10-76 
409 
0-1043 
94-0 
10-72 
395 
0-1040 
47-0 
10-70 
385 
0-1038 
13-5 
10-68 
350 
0-1032 
9-0 
10-72 
324 
0-1027 
2-5 
10-72 
301 
0-1022 
1-3 
10-72 
272 
0-1019 
&c. 
254 
0-1016 
&c. 
233 
0-1013 ' 
210 
0-1010 
180 
0-1008 
155 
0-1006 
120 
0-1004 
112 
0-1003 
68 
0-1002 
47 
o-iooi 
26 
OTOOl 
12 
0-1000 
4 
0-1000 
3 
0-0994 
1 
0-0988 
076 
0-0988 
* In making the experiments described in this paper, and, indeed, in writing the greater part of the 
paper itself, I have assumed that the logarithmic decrement was a measure of the relative viscosities of 
the different gases, at least until exhaustions were reached at which the viscosity begins to break down. 
Professor Stokes has shown that this is not the case except under certain restrictions, and in a note 
appended to this paper he has deduced the results which follow from my experiments when reduced 
according to strict dynamical principles.— W. 0., August 11, 1881. 
