34 R. HOSKING. 



THE VISCOSITY OP WATER. 



By Richard Hosklng, b.a. (Camb.), Physics Master, 

 Sydney Grammar School. 



[Communicated by Prof. Pollock, d. sc ] 



[Bead before the Royal Society of N. 8. Wales, June 2, 1909.~] 



In a paper on the above subject 1 read before this Society 

 on June 3rd last year, I explained how I had obtained absolute 

 values for the viscosity of water at three different 

 temperatures. I have since examined my reductions more 

 carefully, and have found that the values are, in c.g.s. units, 

 '005500 at 50° C, '008926 at 25° C, and '017897 at 0°'05 C. 

 The last value reduces to '017928 at 0° O. Knibbs 2 has 

 deduced the absolute value '013107 at 10° C, from 

 Poiseuille's observations, and has shown that the data of 

 every other experimenter whose work was published earlier 

 than 1895, including Thorpe and Rodger, were not satis- 

 factory for absolute values. So far as I have been able to 

 examine the work published since 1895, I have reached a 

 similar conclusion with regard to it. In order, therefore, 

 to obtain a complete table of absolute values between the 

 temperatures 0° C. and 100° C, I have revised all my earlier 

 work, 3 and reduced my observations for water by applying, 

 in the reduction formula, as given in my last paper the 

 values n = 1*64; andm=l*158. 4 My results, obtained in this 

 way, are collected in the following table. Each value is 

 obtained by the reduction of double sets of observations. 



1 This Journal, xlii, pp. 34-56. 2 This Journal, xxxi, p. 319. 



3 Phil. Mag., March 1900, May 1902, May 1904. 



4 Boussinesq's theoretical correction is 1'12, but experimentally I 

 obtained the average value 1*158 for four tubes which had been treated 

 in exactly the same way as those used in these earlier experiments. 



