1818.] and Cast Iron. 291 



those substances powdered, or by sprinkling them over with 

 them, and that no more heat than is absolutely necessary to 

 effect their union be employed ; and thus the properties of the 

 steel will be as little injured as possible by the process. 



I may also add, that it is no unfrequent practice amongst 

 country smiths to unite cast iron to wrought iron in place of 

 steel, and particularly for the coulters and shares of ploughs, on 

 account of its cheapness ; and possibly, for such coarse purposes, 

 it may answer tolerably well. 1 am, Gentlemen, 



Your most obedient servant, 



Thomas Gill. 



Article XI. 



Prof. Berzelius on the Discovert/ of a new Alkali and a new Metal. 



(To Dr. Bostock.) 



MY DEAR SIR, Russell-square, March 25, 1818. 



In sending you the abstract of Professor Berzelius's letter 

 which you have asked of me for the Annals of Philosophy , I think 

 it right to state, that he has given me no instruction or authority 

 whatever to make such a communication to the public. But as 

 I see no expression in the letter from which I can infer that the 

 Professor would object to this step, and as I have every reason 

 to think that I can depend upon his friendly indulgence, I ven- 

 ture to comply with your request, especially as I feel the same 

 desire as you do, that the interesting discoveries in question 

 should be made known without delay to the British public. 

 Believe me ever, my dear Sir, very truly yours, 



Alex. Marcet. 



A young chemist of great merit, Mr. Arvedson, who works in 

 my laboratory, has just discovered a new fixed alkali. This 

 alkali is found in a mineral from the mine of Uten, in Sweden ; 

 the mineral was discovered some time since by M. D'Andrada, 

 aud called by him petalite. It is composed, in round numbers, 

 of 80 parts of silex, 17 of alumina, and three of the new alkali. 

 This new alkali is distinguished from the old ones : 1 . By the 

 fusibility of its salts; its sulphate and muriate liquify before they 

 arrive at a red heat, the carbonate at the moment when it begins 

 to become red. 2. By its muriate, which is deliquescent, like 

 the muriate of lime. 3. By its carbonate, which does not readily 

 dissolve in water, while it communicates to it precisely the same 

 taste with the other alkalies : the carbonate, when raised to a 

 red heat in a platinum crucible, attacks the platinum as if we had 

 employed the nitrate of potash or of soda. 4. By its great capa* 



r2 



