Spread of Liquids on Solid Bodies. 325 



meridional curve of a bubble* of a fluid 2, of specific gravity 

 <t, under a level glass plate, are found (subject to a small cor- 

 rection dependent on the diameter of the bubble) the cohesion 

 a and *the edge-angle 6 by the equations 



e 



K 



cos~ = 



2 K-k^/2 



(?) 



If we call h the mean ascent, and S the edge-angle of the 

 same fluid in a glass tube of radius r, then 



rha 



(a) = « cos 3 = 



2 



or, dividing equation (9) by equation (7), 



_ (a) _ rh 



00S 3=— = {K _ k y 



(9) 



(10) 



If plates and tubes are made of the same sort of glass, the 

 values of the edge-angles 6 and 3 found from equations (8) 

 and (10) must be equal. 



I have in a former communication f measured for equal 

 times the heights of flat air-bubbles under a glass plate, and 

 the elevation, in newly-drawn glass capillary tubes, for a series 

 of simple liquids. They yield the following values of the edge- 

 angle. 



Table I. 



Liquid. 



Specific 

 gravity. 



Cohesion. 

 a. 



Air- 

 bubbles. 

 Edge-. 



e. 



Capillary 

 tubes, 

 ingle. 



Water 



1 

 0-9136 



1-2687 

 0-7977 

 1-4878 

 0-8867 

 07906 



mgr. 

 8-253 

 3-760 

 3-274 

 3-233 

 3120 

 3 033 

 2-599 



25 32 

 21 50 

 32 16 



36 20 



37 44 

 25 12 



28 48 



29 34 



«o°) 



37 28 

 28 50 

 24 14 



30 35 



Olive-oil 



Bisulphide of carbon .. 



Petroleum 



Chloroform 



Oil of turpentine 



Alcohol 





* Compare with M. Quincke's paper in Pogg. Ann. cxxxix. (1870), and 

 Phil. Mag. [IV.] vol. xli. No. 273, p. 249 (April 1871). 



t Pogg. Ann. cxxxix. p. 15 (1870) ; and Phil. Mag. [IV.] vol. xli. 

 No. 273 (April 1871), p. 252. 



