35 



cannot produce arnmoniacal nitrate with silver, the peculiar 

 reaction due to the true arsenical sublimate. In concluding, 

 allow me to lay before the Society, a few experiments which 

 I have made, for the purpose of shewing the delicacy of 

 Reinsch's test, and its applicability to organic mixtures : — 

 Experiment 1st. — 2 drops of a solution of arsenious 

 acid in water=.02 grain were mixed with 1 drachm of 

 water and muriatic acid, and 3 slips of copper were stained 

 as 60on as the liquid boiled. In this case, taking the 

 quantity of arsenic as unity, and supposing the liquid 

 water, the degree of dilution will be equal to 2785. 



Experiment 2nd. — 1 drop of the solution=.01 grain of 

 arsenic was mixed with 1 drachm of water and acid, and three 

 slips of copper, they were stained as soon as the fluid fully 

 boiled ; when the liquid was reduced to \, the slips were re- 

 moved, dried and heated in a tube, a distinct white crystal- 

 line sublimate was obtained. The degree of dilution, in 

 this case, supposing the liquid water, was in the first place, 

 equal to 5470 ; when the copper was removed, it was equal 

 to 1367^ 



Experiment 3d. — 1 drop of the solution = .01 grain of arse- 

 nious acid was mixed with water and muriatic acid, 4 square 

 inches of copper surface were fully coated ; these, when heated 

 in a tube,yielded a distinct white chrystalline sublimate, giving 

 a yellow precipitate when dissolved in water and mixed 

 with arnmoniacal nitrate of silver, the quantity of metallic 

 arsenic in this case was ^ , and this small quantity was 

 diffused over 4 square inches of copper surface. 



Experiment 4th. — 1' grain of arsenious acid was mixed 

 with 1 oz. bread, 4 drachms water, and some muriatic acid. 

 Three copper slips were stained before^ the water was evapo- 

 rated off ; when £ the water was evaporated off, the copper 

 slips had a dark iron grey coating throughout: these 

 were removed and 4 fresh slips introduced, the fluid was 

 evaporated to a syrupy consistence, when the copper came 

 out nearlv as much stained as the first set. 



