Kt'-zv Puhlicaimis. 275 



f>f chemical knowledge by minute in(lrii(ftlons for the per- 

 formance of ex'periments. — Part 11, Diredions for the ana- 

 iyfcs of mineral waters, of earths and ftones, of ores of me- 

 tals, and of mineral bodies in general. — Part III. Inllruc- 

 tions for applying chemical teiis and re-agents to various 

 ufcful purpof'es. I1ic plan and objects of the work, as t^e 

 nuthor hinifelf obfervcs, are fiifficicntly difiincil from every 

 other compendium of chemillrv to authorife its addition to 

 the cxtenfive iiii: of elementary work?. One object propofcd 

 to be fulfilled by this epitome is, *' that it may ferve as d 

 companion to the colleiStions of chemical fubftances, which 

 the author, by the repeated applications of Undents of this 

 fcience,^has been induced to fit up for public Aile. The 

 utility of thefe collections has hitherto been limited by the 

 want of a concife but comprehenfive code of inftru^tions for 

 their ufe. With the concurrent aid of the firft part of this 

 work, and of a correfj^onding che(t of chemical re-agents, 

 the labours of the lludeut cannot tail to be much facilitated 5 

 for one of the principal clifficiilties in ftudying chcmiftry ex- 

 perimentally, is the acquifition of a great variety of fubftanccs, 

 many of which are not cafy of attainment." 



'I'he following extracts refpe^ing the methods fbr afcer- 

 taining the purity of chemical preparations. Sec. are frpm 

 Part III. 



Acetic Ac'iu — AciJiim Acctofum of the London Pharmacopoeia, 



Radical or concentrated Vhicgat. 



*' This acid is often . contaminated by. fulphureous and 



fulphuric acid. The firft mav be known by drawing a little 



of the vapour into the lungs, when, if the acid be pure, no 



unplcafant fenfalion will be felt; but, if fulphureous acids be 



contained in the acetic, it will not fail to be difccvered in this 



mode. The fulphuric acid is detected by muriatcd barytes ; 



oopper by fuper-faturation with pure ammonia; and lead by 



fulphufet of anmionia. .. *. 



'^ The fpccific gravity of t histoid (Itould be lO^^Q-at leafti 



<f Acetous Acid—Acetzim BifttUatum, P. L, DijlUhd 



Vinegar. 



' *^ If viwcgar be diftilled in copper vefffls, it can hardly fail 



' >I m :j b<4ing 



