Reiset's Compounds. 

 NHs.PtO.NHj+Cl 

 NH3,PtO,NH4 + I 

 NH3,PtO,NH4 + 

 (N H3, Ft 0, N H4 + 0) S O3 



Compounds of Quinine. 

 (aoHsJOjNH^ + Cl 



(C2oH8)02NH4 + I 



(CooH8)02NH4 + 

 (CooH8 0oNH4 + 0)S03. 



On detecting minute quantities of Arsenic and Antimony. 403 



is so great, that it permits no doubt as to the identity of their 

 constitution with that of this body. It now only remains for 

 me to show, by comparison, the greatness of this analogy by 

 the substitution of the platinum compound by an organic 

 oxide. 



Comps. of Cacoplatyl. 

 HPtKd+Cl 

 H Pt Kd + I 

 H Pt Kd + 

 (H Pt Kd + 0) S O3. 



The formation of tirea (a body which possesses all the pro- 

 perties of an organic base, and may be considered as a cyanate 

 of oxide of ammonium) belongs to the same class of phaeno- 

 mena. In that compound an oxide of cj'anogen (cyanic acid) 

 occupies the place of the oxide of platinum in Reiset's ammo- 

 nium compound, and unites with ammonium to give rise to a 

 compound radical, if such it may be considered. The radical 

 (Cy O, N H4) which forms part of urea, is in every relation 

 similar to cacoplatyl; the oxide of that radical, or urea, being 

 of all this class of compounds that which approaches most 

 closely to the oxide of cacoplatyl, (Cy O, N H4) + = nrea. 



LX. On detecti?ig viinute quantities of Arsenic and Antimony, 

 By R. H. Brett, Ph. D. 



To RicJiard Phillips, Esq. 

 My dear Sir, 

 pJAVING been lately engaged in a set of expei-iments made 

 -'--■■ for the purpose of ascertaining the minimum of arsenic 

 and antimony capable of being detected by decomposing the 

 gases which they respectively form with hydrogen, according 

 to the principle of Marsh, I have sent you the results of 

 such experiments, as I think they may perhaps be of some 

 importance, especially in a medico-legal point of view. I may 

 here observe, that the apparatus I employed in these experi- 

 ments is one which I have been in the habit of using for the 

 last three or four years for the purpose of detecting arsenic, 

 and is a mere modification of Dccbereiner's hydrogen lamp : 

 the lower vessel for generating the gas is 8^ inches in height 

 and -t inches internal diameter, capable of containing about a 

 quart of fluid ; near the upper part is a glass tube forming a 

 right angle with the sides of the bottle, and to this glass tube 

 is cemented a brass stop-cock 2 inches in length, with a small 

 pin-hole jet. When generating hydrogen gas in this apparatus, 

 I prefer using rolled zinc cut into portions of about one inch 

 or half an inch square ; these are placed at the bottom of the 

 2 E2 



