66 



On Calculating Surface-Tensions. 



has been employed by Lord Rayleigh * to calculate the wave- 

 length in an oscillating water-jet, and leads, as he himself 

 points out, to too low a result. Had he made use of the cor- 

 rected value (T='0735 gr. = 72'l C.Gr.S. units), the results of 

 p. 82, loc. cit., would have been in very close agreement with 

 theory. 



In conclusion, I would remark that the great value of this 

 particular paper of Prof. Quincke's does not, as it seems to 

 me, depend so much on the absolute accuracy of the results 

 presented as on the emphasis with which, at the time it was 

 written, it represented the capillary constant to be measured 

 as a surface-tension, and on the justice of the general con- 

 siderations which are put forward, and which remain un- 

 impeached. 



A. M. WOBTHINGTON. 

 Clifton, Bristol, June 2, 1885. 



P.S. For the benefit of readers of Maxwell's l Theory 

 of Heat/ in which Prof. Quincke's results are given in a 

 synoptic table, I here reproduce the table with the corrected 

 values. Those in brackets I have been unable to check. It 

 must be borne in mind that the numbers in the second column 

 of tensions are still somewhat uncertain. 



The values are given in grammes weight per linear metre. 



Superficial Tensions at about 20° C. 



Liquid. 



Specific 

 gravity. 



Tension separating the liquid from 



Air. 



Water. Mercury. 



Water 



Mercury 



Bisulphide of Carbon 



Chloroform 



Alcohol 



Olive-oil 



Turpentine 



Petroleum 



Hydrochloric acid 



Solution of Hyposulphite "I 

 of Soda J 



10 

 13543 



1-2687 

 1-4878 

 0-7906 

 0-9136 

 0-8867 

 0-7977 

 11 



1-1248 



7-35 



50-28 



2-99 



[3-12] 



[2-36] 



3-39 



2-82 



2-91 



[7-15] 



C-85 







38-44 

 4-09 

 2-63 



1-82 

 113 



[2-83] 



38-44 







[37-97] 



[40-71] 



35-69 



31-07 



23-60 



26-53 



[38-41] 



42-08 



* * On the Capillary Phenomena of Jets/' Proc. Roy. Soc. no. 196 

 (1870). 



