OF ARTS AND SCIENCES. 91 



ble residue was purified by crystallization from boiling alcohol, and 

 dried at 100°. 



0.2G23 g. of substance gave on precipitation with sulphuretted 

 hydrogen 0.1016 g. of mercuric sulphide. 



Calculated for (CjHoBrSJjHg. Found. 



Mercury 33.11 33.38 



It crystallizes from boiling alcohol as a light white feathery mass 

 with a pearly lustre. It does not melt, but is decomposed and black- 

 ened at a high temperature, is essentially insoluble in water, very 

 slightly soluble in cold alcohol, benzol, or glacial acetic acid, freely 

 soluble in hot alcohol (the solution becomes nearly solid on cooling) 

 and benzol, less so in hot glacial acetic acid, but freely in ether and 

 carbonic disulphide. 



Parahrombenzyldisulphide, (CgH^BrCH2)2S2. 



This substance was made from the mercaptan by exposure to the 

 air, and also by acting on the parabrombenzylbromide with an alco- 

 holic solution of sodic disulphide ; the product precipitated with water 

 was purified by crystallization from alcohol, and dried in vacuo. 



0.1600 g. of the substance gave by the method of Carius 0,1487 g. 

 of argentic bromide and 0.1838 g. of baric sulphate. 



Bromine 

 Sulphur 



It crystallizes in radiating groups of white needles, and has a not 

 unpleasant aromatic smell; melting-point, 87°- 88°. It is essentially 

 insoluble in water, slightly soluble in cold alcohol, and almost insolu- 

 ble in cold glacial acetic acid, but freely soluble in both these solvents 

 when hot, and in ether, benzol, and carbonic disulphide. 



The following table gives the formulas and melting-points of the 

 substances described in this paper. 



N^ame. Formula. 



Parabrombenzylsulpho-acid 



Potassium Salt* CeH^BrCH^SOgK 



Calcium Salt (C6H,BrCH2S03)2Ca 



* The solution saturated at 18° contains 6.20 per cent of the salt. 



