On the Genuintnefs antf Purity ofHrugt and Medicines. t€ft 



hl'ttrated Oxide of Mercury. Red Nitrated ^Icifilver.—^Vh. L. 



Moft of the red nitrated oxide of mercury met with in the (hops is adulterated with red 

 oxide of lead. This fraud may be difcovered in the fame manner, as in the red fulphuratcd 

 oxide of mercury. Genuine red nitrated oxide of mercury is totally volatile on being expofed 

 to a red heat, and foluble in nitric acid, without effervcfcence, but with a developement of 

 V heat. Sulphuric acid converts it into yellow oxide of mercury (Turpeth mineral) ; muriatic 

 acid forms corrofive muriate, and when completely faturated, fweet muriate of mercury* 

 or calomel *. 



JFhite Oxide of Mercury. White Calx of ^ickjiiver.—?h. L. 



Inftead of pure white oxide of mercury, we frequently meet with a mixture of white 

 oxide of mercury, and white oxide of lead, to which, not feldom, a confiderable quantity 

 of chalk is intimately mixed. White oxide of lead is difcovered by digefling one part of 

 the oxide with four of acetic acid, decanting the fluid, and adding to it a fmall quantity of 

 fulphuret of ammoniac, or water Impregnated with fulphurated hydrogen. An almoft 

 black precipitate will be formed, which on the addition of fulphuric acid will not be rc- 

 diflblved. The prefence of calcareous earth may be inveftigatcd as direfted before. 



Genuine white oxide of mercury Is of a fiiowy whilenefs, taftelefs, and inodorous; In- 

 foluble in acids, ponderous; does not become black when rubbed with frefh prepared lime-, 

 water, is totally volatilifed by heat, and when accurately prepared, may thus be converted > 

 into calomel by mere fubllmation. 



Telloti) Oxide of Mercury. Vitriolated ^dckjiher. — ^Ph. L. 



Is feldom found adulterated. But from a carelefs and flovenly management during the 

 procefs for obtaining It, It often contains a confiderable quantity of free fulphuric acid. It 

 then has a perceptible acid tafte, and difturbs the folution of muriate of barytes. It Ihould 

 be totally volatile by heat, and poflefs moft of the chara£lerlftics of the preceding mercurial 

 prepfiratlons. 



Siveet Muriate <f Mercury obtained by Precipitation, Mild Murimted ^lickflver. — Ph. L. 



This preparation being preclfely the fame as calomel, ought therefore to poflefs all Its 

 peculiar properties. But as It Is fpecifically lighter than calomel, It is found adulterated 

 with ftarch, or with white oxide of bifmuth. The firft fraud may be detefted by expofing 

 it in a clofe veffel to a red heat ; as by this means the calomel will fublime, and leave a 



• This produft, if obtained according to the rules of the Rftyal College of Phyficians, muft be Conta- 

 minated with a certain quantity of corrofive fubliraate, on account of the prefoibed quantity of mtirlatic 

 acid to be ufed. Did the guardians of health wift to unite a certain quantity of this deadly poifon with 

 the red oxide? or did they credit the notion, that the produ6l v/ould have a more fparkling appearance, 

 which in general is looked upon as the charaSfriftic of cxcdleney,^ &c. ?. 

 • Vol. IV.— July 1800. Y black 



