402 
MR. W. CROOKES ON THE VISCOSITY 
Table I. (continued).—Log. dec. of dry air at pressures between 1000 M and 0'02 M. 
Temp. 15° C. 
Pressure. 
Log. 
Repulsive force 
Mean free path of molecules. 
M 
decrement. 
of radiation. 
Millims. 
1000 - 0(=0 - 76 m.m.) 
0-0988 
24 
0-10 
905-0 
0-0983 
3-2 
o-ii 
736-0 
0-0975 
3-5 
0-14 
590-0 
0-0971 
4-5 
0-17 
495-0 
0-0966 
5'5 
0-20 
385-0 
0-0960 
8-5 
0-26 
300-0 
0-0952 
io-o 
0-33 
248-0 
0-0943 
12-0 
0-40 
219-0 
0-0937 
14-0 
0"46 
183-0 
0-0930 
16-5 
0'55 
165-0 
0-0926 
18-0 
0-61 
157-0 
0-0925 
19-5 
0-64 
135-0 
0-0907 
21-3 
0-74 
116-0 
0-0892 
24-5 
0-86 
100-0 
0-0876 
27-0 
1-0 
93-0 
0-0866 
29-0 
1-1 
81-0 
0-0842 
31-1 
1-2 
79-0 
0-0840 
31-5 
1-3 
72-0 
0-0824 
32-9 
1-4 
68-0 
0-0817 
33-5 
1"5 
62-0 
0-0799 
34-6 
1-6 
53-0 
0-0774 
37-0 
1-9 
39-0 
0-0710 
41-4 
2-6 
36-0 
0"0695 
42-5 
2-8 
29-0 
0-0657 
42-6 
3-4 
24-0 
0-0620 
41-2 
4-2 
19-0 
0-0577 
OO 
00 
CO 
5-3 
13-0 
0-0500 
30-9 
7-7 
11-0 
0-0460 
27-1 
91 
8-0 
0-0390 
223 
12-5 
7-2 
0-0372 
20-2 
13-9 
5-9 
0-0337 
17-0 
16-9 
4-1 
0-0281 
13-1 
24-4 
3*4 
0-0256 
11-5 
29-4 
2-6 
0-0225 
8-5 
38-4 
1-9 
0-0198 
7-1 
52-6 
1-3 
0-0175 
4-2 
76 - 9 
1-0 
0-0161 
2-1 
100-0 
0-55 
0-0144 
2-0 
181-8 
0-46 
0-0135 
1-7 
217-4 
0-22 
0-0118 
1-4 
454-5 
0-14 
0-0114 
1-0 
715-9 
0-06 
0-0097 
0-7 
1666-6 
0-02 
0-0072 
0-5 
5000-0 
0-00537 
? 
