Capillarity of Molten Bodies. 



93 



12. I was interested to note the values of the constants of ca- 

 pillarity for water and mercury by this method of drops, as I had 

 made numerous determinations of them at the usual tempera- 

 tures by other methods. As the following Tables show, the re- 

 sults gave very different values (especially for water) for the con- 

 stants, according to the speed with which the drops were formed. 



The numbers obtained for mercury are usually smaller than 

 those resulting from my own previous determinations*|(from55*21 

 to 58*79 milligrammes) ; but they differ from the results of other 

 observers, which were obtained by much more accurate methods 

 (elevations in tubes, and drops on a horizontal surface) by incon- 

 siderable amounts. According as the measurements were made 

 immediately after the formation of the surfaces or at a later time, 

 the results for a ranged for mercury between 40 and 50 milli- 

 grammes. 



Mercury. 





Slow. 



Quick. 



2r. 



W. 



et. 



W. 



et. 



millims. 

 1-029 

 0-308 



grm. 

 0-1307 

 00422 



mgrms. 

 40-42 

 43-62 



grm. 

 0-1359 

 00522 



mgrms. 

 42-06 

 57-06 



Water. 



2-478 

 0-493 



00422 



0-0097 



5-428 

 6-259 



,00450 1 5-781 

 ,00170 10-96 



13. By observation of the capillary elevations, the following 

 results were found for water : — 



Gay-Lussacf • . . a = 7*565 

 Hagent .... =7*558 

 By weighing the capillary-raised meniscus, 



Wilhelmy§ . . . =7*945 

 I had myself determined the capillarity-constant for water 

 ten years ago, when I observed the elevation on the inner wall 

 of a thin-walled glass cylinder of about 50 millims. diameter. 



Distilled water was boiled in a glass vessel with vertical walls 

 till about two-thirds of the fluid was left. While the water 

 was still boiling the vessel was corked, and a glass rod with 



* Pogg. Ann. vol. cv. p. 33 (1858). 



t Poisson, Nouvelle Theorie de V Action Capillaire, p. 113 (1831). 



X Abh. d. Berl. Akad. 1845, p. 34. 



§ Pogg. Ann. vol. cxix. p. 186 (1863). 



