VISCOSITY OF WATER BY THE EFFLUX METHOD. 141; 
The only anomalous result in the above table is that for 700 
atmospheres ; the value is probably too small. 
Effect of Pressure on the Fluidity at various Temperatures, 
according to Réntgen’s and Cohen’s experiments. 
Temp. Pressure in Atmospheres. 
! 24 100 200 = 30 600 700 900 
YY — 0215 —— 0327 —~— —— 0670 —— —— 
 — cine 9 Hines lS Crem 
OO — —— 
— 15° —— 0057 0127 0154 0221 0233 0239 0237 0277 
23° —— 0047 0077 — 0100 —— —— 
Nore.—The fluidity under a pressure of one atmosphere is unity for 
nse temperature: that at any other pressure is 1 + the decimal in the 
e. 
The available information is insufficient for the deduction of a 
general formula expressing the fluidity as a function of temperature 
and pressure, for as pointed out by Cohen it is yet undetermined 
whether at higher temperatures the viscosity instead of being 
diminished by pressure, is increased.1 
21. The value of the viscosity by the rotating cylinder method.— 
The values of the viscosity of water as found by other methods 
have differed greatly from that obtained by the efflux method. In 
@recent investigation by Brodmann, this difficulty though not 
completely is at any rate partially resolved. From experiments 
_ of type (6) § 1, using three cylinders of different sizes,” he obtains 
~ following values (i) and (ii) for the viscosity at 15° C. respec- 
mrely from the smallest and middle, and smallest and greatest 
Cylinders. Poiseuilie’s value (iii.) as deduced herein is indicated 
also for comparison 
(i.) a5 = 0-01265 + 0:00049 | 
(ii) m5 = 0-01228 + 0-00011 
(iii) 5 = 0-01143 
7 ute ets p. 684, 
Wied. Annal. Ba. 45, p. 178, see also p. 179. 
