J 1 8 Examtnatkn of the Purity af Mt'Jidne/, life. 



Fig. 4. is a perfpe£tivo riew of the woaden box, a fe£tion of which Is leen in the fore- 

 going figure. (See g, A, », k, fig. 3.) 



Fig. 5. and 6. reprcfent the blunt borer n joined to the iron bar «; to which it was faft- 

 ened. 



Fig. 7. a«d 8, rcprefentthe fame borer with its iron bar, together with the pifton, which, 

 in the experiments No. 2. and No. 3. was ufed to clofe the mouth of the hollow cylinder. 



IV. 



Jn Attempt to dlfcover the Genuimnefs and Purity of Drugs and Medical Preparations. 



By I'RKDEUICK ACCVM. 



To Mr. NICHOLSON. 

 Sir, 



V^F aH the poffible frauds hitherto pra6lifcd by mercenary traders, there is none more 

 intimately conne£led with the welfare of mankind than the art of making or counterfeit- 

 ing drugs and adulterating genuine medicines. 



This unprincipled art is brought to fuch perfeAion, that fpurious articles are every 

 where to be fGUi>d in the market, made up with fuch dexterity, that not only the mere 

 merchant and drug broker, but even the man of (kill, is fometimes deceived. 



The influence of this pra£lice has indeed been obferved by medical men of faience,, 

 and the rulers of this art have thought it their duty to appoint a court of examiners 

 to invefligate the goodnefs of drugs and medicines in the different chemifts' and apothe- 

 caries* fnops in this metropolis. 



How far this great woric is accomplifhed, or to what extent the whole undertaking 

 docs either honour and credit to the fagacity of thefe learned, liberal, and upright ex- 

 aminers, or affords juftice to the public, I fhall leave to the determination of every indi- 

 vidual who has once onFy been honoured with their vifit. 



But as moral duty fliould (timulate every individual to offer all the afliftance in his power 

 to fupprefs or check fuch deteftable praftices, I have ventured to recommend that me- 

 thod which, if judicloufly executed, will contribute in no fmall degree to the public good 

 in this Tefpe£V. If thefe (ketches fhould tend in any meafure to put the unwary on their 

 guard, I fhall think myfelf amply rewarded, and (hall not fail to extend them from time to 

 ♦irae, and lay them before the public with fome confidence. 

 No. IT, Hay-market, FRED. ACCI7M. 



May ifi, 1 79!?. ««__ 



Examination of Saline Substances. 

 Sulphuric Acid. 



THE vitriolic acid kept in our (hops under the name of oil of vitriol, ufually contains 

 not only lead in folution, but likewi'fe iron, copper, and fulphate of potafh. 



In order to difcover thefe admixtuires, a little of the aci*t mult be diluted with diftilled 

 water and faturated with pure vegetable alkali, as by this means tl*e copper, iron, and 



S Icai 



