465 



APPENDIX D. 



Account of some Remarkable Facts observed in the Deoxidation of 

 Metals, particularly Silver and Copper, by Samuel Lucas, Esq., 

 of Sheffield (Read March 6, 1818). In a letter to Mr. Dalton. 

 Memoirs of Lit. and Phil. Soc. Manchester, vol. viii. 



Page 271. . . . 'Dear Sir, When I had the pleasure of seeing 

 you in Manchester, I mentioned having observed that pure silver, 

 when melted and while in a fluid state, had the property of uniting 

 with a small proportion of oxygen, not only from the atmosphere, 

 but also from other bodies which gave it out at a suitable degree of 

 heat, as some of the nitrates for instance ; and that the oxygen 

 thus absorbed remains united with the silver only so long as it 

 continues in a fluid state, or while fluid, until some substance be 

 applied having a more powerful attraction for the oxygen. In 

 proof of this I now send for your inspection a few specimens of 

 silver that has been in the different states, and which carry the 

 external marks ; and also a bottle of the gas collected from silver, 

 which had been exposed to the influence of the atmosphere by 

 cupellation.' . . . 



Page 2 7 2. ... 'If, instead of cooling gradually, it be made to 

 assume the solid state suddenly by pouring it into water, still the 

 same phenomena occur ; an ebullition takes place, and oxygen gas 

 is evolved ; but as the silver is so much divided and passes so 

 suddenly from the fluid to a solid state, the protuberances are 

 proportionally minute, and are spread more equally over the 

 whole surface, as will be seen in specimen No. 2.' ... 



Page 273. . . ( Thus, if charcoal be spread, for a few moments 



H H 



