752 
PROFESSOR 0. REYNOLDS ON CERTAIN DIMENSIONAL 
Table XI. — Showing the pressures of hydrogen at which the ratio of the difference 
of pressure to the mean pressure is the same for meerschaum No. 3 and stucco 
No. 1. 
Ratio of mean 
pressure to 
difference of 
pressure. 
Corresponding pressures. 
Ratio of 
Meerschaum 
No. 3. 
Stucco 
No. 1. 
corresponding 
pressures. 
44 
inches. 
35 
inches. 
5-8 
6-0 
43 
34 
5-5 
6-2 
40 
32 
5-0 
6-4 
39 
30 
4-8 
6-2 
38 
29-5 
4-6 
6-4 
37 
29-5 
4-4 
6-7 
36 
27 
4-2 
6-4 
32 
22 
3-4 
6-4 
29-5 
18-5 
2-9 
6*3 
31 
18 
3-2 
5-6 
30 
18 
3-0 
6-0 
25 
12 
2-0 
6-0 
24-6 
11-40 
1-9 
6-0 
25 
11-50 
2-0 
5-25 
21 
7-70 
8-0 
9-7 
24 
7-60 
1-7 
4-5 
In Tables X. and XI. the first columns are the ratios taken direct from Tables VIII. 
and IX., the second columns are the pressures also taken direct from Tables VIII. 
and IX. 
In order to find the pressures with the stucco plate which would yield exactly the 
same ratios (difference of pressure to mean pressure) as those in the table, the numbers 
in the ratio columns of Tables VI, and VII. were plotted, the mean pressures being 
taken as abscissae. The points were joined so as to form curves, and then finding 
points on the curve whose ordinates corresponded to a particular number in the first 
column, the abscissae gave the numbers required for the third column in Tables X. 
and XI. In this way the numbers in the third column are rather more uniform than 
they would have been had they been the results of actual observation. 
Tables X. and XI. show T that within the limits of accuracy of the experiments the 
pressures in the stucco correspond with pressures in the meerschaum six times as 
great. This is exactly according to Law V., Art. 7, from which it appears that the 
numerical relation between the corresponding pressures is the relation between the 
diameters of the interstices of the meerschaum and stucco plates. This fact also is 
confirmed, for not only does it appear that the ratio is independent of the mean 
density of the gas, but it is the same for hydrogen as it is for air, showing that the 
relation depends only on the nature of the plates. 
