Professor Davy's Keiu Metals. 373 



hundred weight of copper and zinc). The solid caustic 

 potash was used, sHghtly moistened by the breath. The 

 metaloid obtained was highly inflammable, swam in recti- 

 fied naphtha, but was difficultly separated from the potasli, 

 in which it is plentiRiHy imbedded, after being exposed to the 

 Galvanic action. Waaler Ijeing dropped upon it, the particles 

 explode similarly to grains of gunpowder thrown into the (ire. 



The metaloid obtained from soda is not so highly infl un- 

 mable, and can therefore be collected more easily. A glo- 

 bule about the size of a small tare being thrown on paper 

 moistened, instantly became apparently red-hot, and, run- 

 ning off the surface of the paper, fell luminously through 

 the air. 



Mr. Allen has also repeated Mr. Davy's experiments, and 

 obtained both the metaloids by four troughs of fifty pairs 

 each of sixteen inches surface. The metaloids obtained by 

 Mr. Allen were exhibited by Dr. Marcet at the Theatre of 

 Guy's Hospital. ^ 



Mr. Dibdin, in his introductory lecture at the Royal Insti- 

 tution, a few days ago, announced that some of the primi- 

 tive earths, as they are called, such as Barytes ami Strontian, 

 having many alkaline qualities, Mr. Davy was induced 

 to submit them to similar experiments, and has discovered 

 that these also consist of metallic bases, united to oxygen, 

 forming con)pound bodies analogous to the two fixed alkalies. 



To Mr. Tilloch. 



SIR, London, Jan. 24, 1 808. 



I AM convinced you would not wish any mistakes to re- 

 main uncorrected in your excellent Magazine. 



I have just read the account given in the A'umber for 

 November, of Mr. Davy's Bakcrian Lecture. Your Report, 

 I am sorry to sav, m> in some particulars not quite correct. 

 I was present at the reading of the paper before the. Royal 

 Society, and I paid particular attention to the statements 

 of facts. 



It will be merely doing justice to the author, to mention 

 accurately the particulars of his important discovery. 



A a i It 



