Spread of Liquids on Solid Bodies. 



337 



for water as fluid 3, we obtain the following values from my 

 earlier observations * : — 



Table VIII. 



Liquid. 



Specific 

 gravity. 



Alcohol I 07906 



Petroleum 7977 



Chloroform 



Turpentine 



Olive-oil 



Bisulphide of carbon 

 Water 



1-4878 

 0-8867 

 0-9136 

 1 -2687 

 1 

 Mercury I 1354,3 



Capillary Air- 

 tubes, bubbles. 



mgr. 

 2-^37 

 2 566 

 2-733 

 2-765 

 3271 

 3-343 

 7235 



mgr. 

 2-352 

 2-604 



2-398 

 3-490 

 2-768 

 7-4J9 

 34-53 



Surface-tension 

 against glass. 



Capillary 

 tubes. 



mgr. 

 4-998 

 4-669 

 4-502 

 4-470 

 3-964 

 3-892 

 



Air- 

 bubbles. 



5097 

 4-845 



5051 ! 

 3959 

 4-681 

 



27-081 



In this Table the liquids are arranged according to the value 

 of their surface-tension at the boundary of glass, as follows 

 from the observations upon capillar}* tubes. 



With the exception of mercury, the bound ing-surface of glass 

 and alcohol exhibits the greatest, and that of glass and water 

 the smallest surface-tension. Instead of which we may also 

 say alcohol has the least, water the greatest adhesion to glassf. 



A similar calculation may be carried out in the case of all 

 the aqueous saline solutions for which I have lately J established 

 the values of a. According to equation (5 c), in the case of all 

 saline solutions for which (a) increases with augmented con- 

 centration, the surface-tension of the common bounding surface 

 of glass and saline solution will be the less, and the adhesion 

 of the saline solution to the glass will be the greater, as the 

 saline solution is the more concentrated. This occurs for all 

 the substances investigated by me, with the exception of hy- 

 drochloric acid, nitric acid, and ammonia ; and it holds also for 

 alcoholic solutions of chloride of lithium and chloride of cal- 

 cium §. Besides, the same quantity « ]2 may be calculated in 



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

 No. 273 (April 1871). 



t For melted glass I have found (Pogg. Ann. cxxxv. p. 642, 1868) 

 otj = 18*09 mgr. ; and since this value was necessarily obtained with a 

 lowering temperature, there is nothing astonishing in the value «j>34-53, 

 as follows from equation (5 a) and the observations on mercury. Accord- 

 ing to this equation, ct l must always be greater than a value of ot 2 cos 6. 



\ Pogg. Ann. clx. pp. 371-374 (1877), table xi. § Loc. cit. p. 566. 



Phil. Mag. S. 5. Vol. 5. No. 32. May 1878. Z 



