356 Steel-making ly the Diamond. — JJfay ef Pewter. 



The fu'"n of the Iron being perfect to fuch a degree as to exhibit the rudiments of the 

 mod beau :f 1 cryfta'.lization on its furface, it cannot pofllbly be imagined that any part of the 

 dia ■ ond.cou d remain unchanged in the mafs, without entering into a ftate of intimate com- 

 bination, becaufe the difference of fpecific is repugnant to fuch a notion. 



The diamond, therefore, difappeared by the attradive force exerted upon it, by virtue of the 

 elevated temperature to wrhich both wrere expofed, in the fame manner as one metal difappears 

 in its mixture or alloy with another. 



Confequently, the diamond did in this experiment afford the fame principle as the charcoal, 

 becaufe it produced the fame compound with iron. 



The converlion into fteel is out of doubt, for the button having been laid bare by the mill 

 of the lapidary, a drop of weak acid immediately produced a fpot of an obfcure grey colour, 

 abfolutely fimilar to that produced on the Englilh caft-fteel, and that fufed by the procefs of 

 Cit. Clouet. They who have often touched fteels by this kind of proof, long fince pointed 

 out by Rinman, have had occafion to remark that the fpot on caft-fteel*, though very per- 

 ceptible, is not fo black as on fteel made by cementation ; a circumftance which probably 

 depends on the different ftate of oxidation in which they may have taken up the carbon. 



Explanation of the Figures, Piatt XVI. 



A, fig. I, is the plan of the iron crucible. 



A is its feftion. 



<?, fig. 2, plan of the ftopper. 



0', k8t\on of the ftopper. 



B C, fig. 3, button of caft-fteel feen in perfpe£livc. At e Is reprefented the fpot formed 

 by the nitric acid on the part laid bare and polilhed. 



Vllf. 



Notice of the Experiments made hy Order of the Minifler of the Interior of France, relative to 



the Finenefs of Tin or Peivter.\ 



J. HE approaching renewal of the meafures of pewter J, which are ufed for wine, and fe- 

 veral other liquors, demanded a knowledge, i. of the degree of purity which the tin ought 



• From very frequent trials of fteel for working ufes, I have been led to adopt the contrary rule, par- 

 ticularly with plate-ftcel. There is a kind of pl.te-fteel fold in London, at feven-pence per pound, which 

 remains white under the fame diluted acid as turns caft-fteel as black as ink. The accurate reporter has, 

 »D doubt, made his trials with different produfts from thofe in our market. — N. 



f Communicated to the Philomathic Society, by Cit. Coquebcrt, and infertcd in their Bulletin, No. 30. 

 Fruftidor, an. VJI. 



+ Eiain, which word is indifcriminately ufed by moft writers for pewter, or alloyed tin, as well as that 

 which IS pure. 



to 



