84 C. E. Linebarger — Relations between the Surface 



received comparatively little attention, although it is univer- 

 sally recognized that there must be an intimate connection 

 between the capillarity and chemical constitution of liquids. 

 HendeleefP seems to have been the first to have entered this 

 field of investigation, being followed a few years later by 

 Wilhemy ;f the work of Quincke;}: on the surface tension of 

 substances at their point of liquefaction should also be men- 

 tioned here. Robert Schiff,§ too, has published extensive and 

 valuable facts and deduced therefrom some important conclu- 

 sions in this domain of research. I will not enter now into a 

 review of these investigations, as they will be frequently 

 referred to in discussing my results. 



Three principal methods have been employed in the deter- 

 mination of the surface tension of liquids; 1°, the capillary 

 tube method, consisting in observing the height to which a 

 liquid rises in a capillary tube of known bore ; 2°, the drop 

 or biibble method, consisting in the determination of the shape, 

 and size of drops or bubbles formed in various circumstances ; 

 3° — the method consisting in ascertaining the force necessary 

 to pull a disk of known area from the surface of a liquid. 

 These methods have, indeed, been very much modified in 

 individual cases, but, in general, all may be referred to one or 

 another of the foregoing. The results obtained by different 

 methods have been found to be quite concordant. 



Most of the determinations of surface tension have been 

 made with one liquid in contact with air, the surface tension 

 of which being so small, could be safely neglected. About 

 the only investigations of the surface tensions of two liquids 

 in contact are those of Quincke (who determined the shape of 

 drops of one liquid resting in another, and the change in the 

 height of a liquid in a capillary tube when subjected to the 

 influence of another liquid, etc.) and of Guthrie. |j These 

 researches are entirely physical, chemical questions being 

 hardly touched, yet as it was Guthrie's work which induced me 

 to take up this subject, and as his methods resemble mine 

 closely, I will describe some of his experiments and cite some 

 of his conclusions. 



From a glass ball, suspended in a funnel-shaped vessel, water 

 was made to drop, the drops being caught in a graduated tube 

 placed at the bottom of the vessel. Funnel and tube were, 

 filled successively with air, " turpentol," and benzene, and the 

 flow of water so regulated that a drop fell everj five seconds. 

 It was found that there were required to fill the tube up to a 



*Compt. Rend.. 1, 52 and li, 97 (1860). fPogg. Ann., cxxii, 55, (L864.) 

 % Pogg Ann., cxxxv, 621. (1868) and ib. cxxxviii, 141. (1869.) ' 

 §Liebig's Ann., ccxxiii, 47, (1884) and Gazz. chim. ital. xiv, 137, (1S84.) 

 || Proc. Roy. Soc, xiii, 444 and xiv, 22. 



