Barium, Sti^ontium, and Calduiii. 295 



they extended may be learned from the following quotations 

 from the Bakerian lectures of that celebrated chemist. In refe- 

 rence to his efforts to isolate the radical in question, the distin- 

 guished lecturer mentions " that to obtain a complete decomposi- 

 tion was extremely difiicultj since nearly a red heat was required, 

 and that at a red heat the bases of the earths acted upon the 

 glass, and became oxygenated. When the tube was large in pro- 

 portion to the quantity of amalgam, the vapor of naphtha furnish- 

 ed oxygen sufficient to destroy a part of the bases ; and when a 

 small tube was employed, it was difficult to heat the part used as 

 a retort sufficiently to drive the whole of the mercury from the 

 base without raising too highly the temperature of the part serv- 

 ing for a receiver so as to burst the tube." "When the quantity 

 of amalgam was about fifty or sixty grains, I found that the tube 

 could not be conveniently less than one-sixth of an inch in di- 

 ameter, and of the capacity of about half a cubic inch. In conse- 

 quence of these difficulties, in a multitude of trials, I had few 

 successful results ; and in no case could I be absolutely certain 

 that there was not a minute portion of mercury still in combina- 

 tion with the metals of the earths."* 



The observations are more than confirmed by my experience, 

 which leads me to the conviction that the removal of the mer- 

 cury is not to be accomplished thoroughly in glass vessels, and, 

 of course that Davy was perfectly correct in supposing that the 

 products which he described as barium and strontium, were alloys 

 with mercury. I am also under the impression that the metals 

 above mentioned decompose naphtha, when heated with its va- 

 por, and enter into combination with its constituents. Had the 

 barium which Davy obtained, been free from mercury, it would 

 not have been fusible below a red heat, as alledged by him. 

 Agreeably to my experience, that metal requires no less than a 

 good red heat for its fusion. 



In a subsequent paragraph he adds : " The metal from lime I 

 have never been able to examine exposed to air or under naphtha. 

 In the case in which I was enabled to distil the mercury from it 

 to the greatest extent, the tube unfortunately broke while warm, 

 and at the same moment when the air entered the metal, which 



* See Transactions of the Royal Society, Part 11. Nicholson's Journal, vol. 

 xxi, for 1808 ; or, Tilloch's Philosophical Magazine, vol. xxxiii. 



