GILDING ON STEEL. 215 



I Iiave feen operators in Germany, who, when (hey con- Improvement. 

 ■ . , , , • /• /• II - t,avity toreceiv 



ftru^led their cupels, had the precaution to form a tmall cir- ^hg fjiygr. 



eular cavity in (he middle, the depth oi' whith was propor- 

 tioned to llie quantity of filver, which from the alTay they 

 knew to be contained in the lead of one operation. By this 

 contrivance there were no infulated grains of the metal left 

 on the furface of their cupel, but thte whole of the filver 

 formed a perfedly round cake in the middle of the center ex- 

 cavation. I would advife the fame ingenious expedient to be 

 ufed in the cupels of fan d, 



I am well aluired that the cupels I propofe, if made with .Conclurion. 

 care and attention, will fucceed perfectly, and that, indepen- , 

 dent of their convenience beyond the others, they will be 

 found very economical. - 1 am defirous that^ for the advantage 

 of metallurgy, this method fliould be generally ufed, and its 

 benefits will prove that we ought not always to follow with 

 fervility the edablithed ufages nor the common working pro- 

 cefles. 



XL 



JLetter from Mr. James Stod art, explaining the Method qf 

 gilding upon Steel b\f Jnwierjion in a Liquii, which has lately 

 engaged the pukUc attention in various Articles of Mai}ii' 

 faciure. 



To Mr. NICHOLSp:^. 

 Dear Sir, 



A Confiderable degree of public intereft and curiolity has Indruments of 

 lately been excited by the exhibition of inftruments of fteel ^.j^^' ^' 

 coated or gilt with gold. The difcovery, although not altOr 

 gether new, does not appear to be very generally known ; 

 and as its application to various manufadures promifes to be 

 both elegant and ufeful, I have, with a view of faving fome 

 time and expence to others who may be inclined to make 

 further experiments, added a fliort account of a method which 

 with me has tucceed<id perfectly well. I wifli here in juftice 

 to obferve, that this difcovery of the method belongs more to 

 my friend Mr. Hume, chemift, Long- Acre, than to m)felf. 

 With that gentleman's kind affiftance I had but few difficulties 



to 



