170 
PROFESSOR O. REYNOLDS ON THE THEORY OF LUBRICATION 
Table I. —Viscosity of Oil compared with Water : 11 April, 1884. 
N amber. 
Third. 
Temperature. 
Time 
seconds. 
r 
107 
experimental. 
log/I 
experimental. 
log n 
calculated. 
r 
107 
calculated. 
Fahrenheit. 
Centigrade. 
i 
Water. 
O 
60 
15-5 
25 
1-640 
2 
99 
99 
99 
99 
99 
o 
9? • 
99 
99 
99 
99 
4 
Olive oil . 
61 
16 
2040 
123-00 
5-08990 
5-090133 
123-06 
5 
99 
81 
1350 
81-00 
6-90848 
6-89807 
79-08 
6 
99 
94 
1000 
60-00 
6-77815 
6-78290 
59-34 
7 
99 • 
120 
555 
33-40 
6-52375 
6-52375 
33-40 
Fig. 3. 
13. The Comparative Values of [x for Different Fluids and Different 
Systems of Units. 
The values of /x given by different writers for air and water, are expressed in various 
units of force and length, so that it is a matter of some trouble to compare them. 
To facilitate this for the future comparative values are here given. Those for water 
have been deduced from Poiseuille’s formula, for air from Maxwell’s formuhe, and 
for olive oil from the experiments recorded in the previous article. 
Idle units of length, mass, and time, being respectively the centimetre, gramme, 
and second, in which case the unit of force is the weight of one 980’5th (p') part 
of a gramme, expressing temperature in degrees Centigrade by T and putting 
P-! = 1 +0-0336793T+0-0002209936T 3 
( 3 ) 
