THE VISCOSITY CF WATER. 43 
The numbers in columns 6 and 7 were used to obtain 
the curves given in Figures 2, 3, 4 and 5. It will be 
noticed that for a considerable distance the lines are 
Straight, indicating constant values fore in equation 2, 
and therefore for m for the particular capillary. This con- 
stancy is remarkable when we consider the enormous speed 
with which the water is forced through the tubes in many 
cases. The individual observations show also that there 
is no variation in any particular case, and that the value 
of m in the general formula can be relied upon, when 
determined in this way. There is therefore no necessity 
to keep the kinetic energy correction small in comparison 
with the first term in determining viscosities by the 
efflux method, provided of course, that the time of flow 
and pressure can be measured with sufficient accuracy. 
This will be shown later, where values have been worked 
out. In certain curves it will also be noticed that at a 
particular point, there is an abrupt change in the direction 
of the line, indicating either a largely increased value for 
m, or a change in the nature of the flow. This is most 
marked in both the curves for Tube IV. and in one of the 
curves for Tube ITI. | 
The following values for C and ec in equation (2) were 
obtained from the curves, and the corresponding values of 
m were deduced by equation (4). 
Tube I. Tube II. | Tube III. Tube IV. 
\ —_———<—<—<——_——< qj] quem _| —— 
RtoL| LtoR|RtoL|LtoR| RtoL|LtoR| RtoL  LtoR 
{- 
| 
' 
C 6350 | 6330 7400 | 7440 | 4570 | 4570 | 5400 | 5390 
10“ x¢| 9°60 POrSl |) 1000) 9:90 pt -78 G18) 1-24 | 7°60 
m | 1-130: 1:164| 1:164] 1-162! 1-128] 1-136 | 1-166 | 1-216 
The values for m are all greater than the theoretical 
value. Thereare also two values for each capillary accord- 
ing as the liquid flows in at one end or the other. This. 
fact is most marked in the case of Capillary IV. 
. 
