(78) HISrORr of the SOCIETr. 



Dr RoeL°ck. dired experience by principles, and to regulate the mechanical 

 operation of the artift by the lights of fcience. The effed^s of 

 that eftablifhment extended, in a particular manner, to all that 

 variety of manufadtures in which gold and filver were required, 

 to the preparing of materials, the fimplifying of the firft fleps, 

 to the faving of expence and labour, and to the turning to fome 

 account what had been formerly loft to the manufadlurer. It 

 is well known, that, while Dr Roebuck refided at Birmingham, 

 fuch was the opinion formed of his chemical knowledge and 

 experience by the principal manufa6l\irers, that they ufually 

 confulted him on any new trial or effort to improve their feve- 

 ral manufadures ; and, when he left tTiat place, they fincerely 

 regreted the lofs of that eafy and unreferved communication 

 they had with him, on the fubjeds of their feveral departments. 

 On account of fimilar circumftances, the benefit to the public, 

 from the eftablifliment of the vitriol works at Preftonpans, in 

 the extenfion and improvepient of many of the arts, cannot nov/ 

 be exadly afcertained. The vitriolic acid is one of the moft ac- 

 tive agents in chemiftry, and every difcovery which renders it 

 cheap, and accefTible to the chemift, muft be greatly fubfervient 

 to the progrefs of that fcience. By the eftablifliment at Prefton- 

 pans, the price of that valuable acid was reduced from fixteen 

 to four pence per pound. It is to Dr Roebuck, therefore, that 

 chemifts are indebted for being in pofTefTion of a cheap acid, to 

 which they can have recourfe in fo many procelTes. 



But Dr Roebuck's objed, in the profecution of that fcheme, 

 was not fo much to facilitate the chemift's labour, as to render 

 that acid, in a much higher degree than it had formerly been, 

 fubfervient to many of the pradical arts. By rendering the 

 vitriolic acid cheap, great ufe came to be made of it in prepa- 

 ring the muriatic acid, and Glauber's falts from common 

 falts. Its ufe has been farther extended to many metallic pro- 

 ceffes; and it has lately been employed in feparating filver from 



the 



