466 



Prof. Guthrie on Drops. 



[Recess, 



the solid and liquid, by altering the size of the surface of contact between 

 the two, that the size of the drop gives no direct clue to the cohesion of 

 the liquid. 



We may now examine a few cases in which, the size of the sphere re- 

 maining the same, and its density in some instances nearly so, the matter 

 of the solid varies, but the liquid wets it in all cases. This will show 

 -whether the differences of Table X. are due wholly to differences of density 

 of the solid, or also or wholly to differences of chemical constitution. 



Table XI.— Water. 

 gt = 2. 

 T=23°C. 

 Radius of curvature = 7 millims. 



1. 



Substance. 



Antimony . 



Sulphur .... 



Cadmium . 



Zinc 



Lead 



Phosphorus 

 Bismuth . . . . 



Tin 



2. 



Weight of 

 20 drops. 



grms. 



r 2-3905] 



J 2-3980 I 



1 2-3968 r 

 12-4016 J 

 f 2-4019 ^ 

 I 2-4067 



\ 2-4046 \ 

 I 2-4063 

 ^2-4022; 

 r 2-4362] 



J 2-4387 

 1 2-4374 f 

 12-4358 J 

 f 2-44951 

 1 2-4481 I 

 I 2-4518 f 

 12-4478] 

 f 2-45221 



J 2-4525 I 

 I 2-4537 [ 

 [2-4528 J 

 r 2-4532] 

 12-4564/ 

 r 2-4528] 

 2-4584 

 2-4580 f 

 L 2-4589 J 

 r 2-4843] 



J 2-4864 



1 2-4829 f 

 [2-4861 J 



Mean weight 

 of single drop. 



grm. 

 0-11984 



0-12021 



0-12185 



0-12246 



0-12264 

 0-12274 

 0-12285 



0-12425 



Specific gravity 

 of solid. 



2-00 



8- 70 



6- 86 



11-44 

 2-08 



9- 90 



7- 29 



Equal spheres of the substances were made by casting them in the same 

 bullet-mould. The surfaces of the metals were roughened by momentary 

 immersion in acid ; tin and antimony in hydrochloric, the rest in nitric 

 acid. Without this precaution a metallic surface is apt to be wetted only 

 locally, the base edge of the drop is irregular and inconstant, and the drop- 



