370 Dr. N. Ernest Dorsey on the Surface-Tension of 



This spring determinations of the surface- tensions of a few 

 solutions were made at concentrations varying from one-tenth 

 normal to normal, and the values found lie upon straight lines 

 starting from the value for pure water. 



Historical and Critical. 



Among those who have worked on the surface-tension of 

 aqueous salt solutions may be mentioned Frankenbeim 1 , 

 Buliginsky 2 , Valson 3 , Quincke 4 , Lippmann 5 , P.Volkmann 6 , 

 0. Rother 7 , Traube 8 , Bontgen and Schneider 9 , Klupathy 10 , 

 Goldstein 11 , Jager 12 , N. Kasanskine 13 , Canestrini l4 , Sentis 15 . 



Excepting Sentis, Jager, and Klupathy, they all used the 

 method of capillary tubes, and Quincke supplemented this 

 with his method of large bubbles. All determinations of the 

 surface-tension from the measured rise of the liquid in capillary 

 tubes involve an assumption in regard to the contact-angle — 

 i. e. in regard to the angle included between the wall of the 

 tube and the tangent to the liquid surface at the point of 

 contact with the tube. This angle cannot be measured ; for by 

 any possible method we must measure the inclination of a 

 finite arc, and as the surface extends on one side only of the 

 point at which we desire the inclination, the finite arc whose 

 inclination we measure must lie entirely on one side of the 

 point of contact. Hence every measured value of this angle 

 will necessarily be too large. This is probably the reason 

 why Prof. Quincke obtains finite contact-angles for liquids 

 that wet the glass in contact with them. 



Another objection to measuring the surface-tensions of 

 solutions at the line of intersection of three bodies — solution, 

 air, and glass — is that probably the tensions of both the 



1 Pogg. Ann. xxxvii. p. 409 (1836). 



2 Pogg. Ann. cxxxiv. p. 440 (1868) ; Ann. chim. phys. [4] xx. p. 361 

 (1870). 



3 Compt. Rend, lxxiv. p. 103 (1872). 



4 Pogg. Ann. clx. pp. 337 & 560 (1877). 



5 Wied. Ann. xi. p. 316 (1880). 



6 Wied. Ann. xvii. p. 353 (1882). 



7 Wied. Ann. xxi. p. 576 (1884). 



8 Journ.f. pr. Che?n. xxxi. p. 192 (1885). 



9 Wied. Ann. xxix. p. 165 (1886). 



10 Math. u. naturwiss. Ber. cms Ungarn, v. p. 101 (1887) ; Wied. Ann. 

 Beibl. xii. p. 750 (1888). 



11 Zeitschr.f. phys. Chem. v. p. 233 (1890). 



12 Acad. d. Wiss. in Wien, 100 2a. p. 493 (1891). 



13 J. de la Soc. phys. chem. Husse, xxiii. p. 468 (1891) ; Jonrn. de Phys. 

 [3] i. p. 406 (1892). 



14 Riv. Sc. ind. p. 33 (1892) ; Wied. Ann. Beibl. xvi. p. 335 (1892). 



15 Journ. de Phys. [2] vi. p. 571 (1887) ; Thesis published at Paris, 

 Feb. 1897 ; Journ. de Phys. [3 vi. p. 183 (1897). 



