10 Mr. Daniell on the Action of Mercury 



therefore, take place ; the balance of force which determines 

 its particular direction in the instances pointed out, forms an 

 interesting subject of investigation, which, together with the 

 cleavage and dissection of crystals, and the manner in which 

 they are affected by light and heat, may ultimately contribute 

 to the explanation of the laws of molecular attraction. 



I shall conclude this paper with the result of some experi- 

 ments upon the mutual action of mercury and platinum. 



EXPERIMENT XIV. 



There is no apparent action whatever between mercury and 

 a bar of platinum, at the common temperature of the atmos- 

 phere ; but when exposed together for a short time to the 

 boiling point of the former, the latter becomes superficially 

 coated with the fluid. The combination is so slight, that the 

 mercury may easily be wiped off mechanically, as water from 

 wet glass. Platinum, which has been kept constantly wetted 

 with mercury for six years, has not become disintegrated, or in 

 any way changed its properties. 



EXPERIMENT XV. 



A few grains of spongy platinum, formed from the ammonio- 

 muriate, were violently agitated with mercury and a few drops 

 of water in a test-tube : a kind of thick scum, or semifluid 

 amalgam, speedily collected upon the surface, from which the 

 still fluid metal could easily be poured off. 



EXPERIMENT XVI. 



The foregoing experiment was repeated ; but the water was 

 acidified with acetic acid. The test-tube was five inches long, 

 and about half an inch diameter. The mercury occupied 

 about an inch, and the weak solution of the acid about half an 

 inch of its depth. The platinum was thrown in, and the whole 

 shaken together for a short time ; when the tube became filled 

 with an amalgam, of the consistence of soft butter. When the 

 tube was upset, a very few drops of fluid mercury ran out of it ; 

 and when the amalgam was shaken out into a saucer, it retained 

 its consistence for many weeks. It possessed a dullish metallic 

 hue, like that of lead which has become tarnished ; and very 



