OF ARTS AND SCIENCES. 219 



observation furnished a very ueat and convenient way of obtaining 

 the corresponding alcohols from the bromides. (See parabrombenzyl- 

 alcohol in the next paper, p. 221). 



The composition of the parachlorbenzylbromide was established by 

 the followino; analvses : — 



0.3399 gr. of the substance gave after ignition with CaO 0.5580 gr. 

 AgBr+AgCl. 



0.4224 gr. of substance gave 0.6779 gr. AgBr-|-AgCl. 



Required for C-HgCl Br. round. 



Chlorine and Bromine 56-20 57-20 55-94 



Pfoperties. — By slow evaporation of its alcoholic solution, it can 

 be obtained in well-formed colorless prisms, by cooling in radiated 

 bunches of needles often three centimeters lonor ; it has an agreeable 

 aromatic odor, and acts on the mucous membrane more violently than 

 any of the other substances described in this jjaper ; it melts at 48 i'^, 

 sublimes in oily drops, can be distilled with steam, is Tery volatile at 

 ordinary temperatures, so that a crystal will evaporate completely if 

 exposed to the air for a few days, and burns with a flame similar to that 

 of the bromine compounds. It is slightly soluble in water, easily soluble 

 in cold, still more so in hot alcohol, and very readily in ether, benzole, 

 carbonic disulphide, and glacial acetic acid. It is attacked with diffi- 

 culty, if at all, by potassic dichromate and dilute sulphuric acid. 



Paraiodbenzylbro>mde,0,.H^ICff,,B)\ WAS made from paraiod toluol ; 

 melting-point, 35° ; prepared according to Koruer* by the action of 

 hydriodic acid on the nitrate of diazotoluol, this last being obtained 

 by Victor Meyer's f excellent modification of Griess's reaction. The 

 introduction of the bromine into the side-chain by treating the boiling 

 substance with bromine vapor was much more difficult than in the 

 preceding cases ; the precautions to be observed were in general the 

 same as those given under parabrombenzylbromide ; but occasionally, in 

 spite of all possible care, a black tarry liquid was the only result of the 

 process. The conditions under which the j^araiodbenzylbromide is 

 formed are now undergoing very careful study by Mr. C. F. Mabery, 

 and the results will be published in his paper upon the paraiodbenzyl 

 compounds. It is a very remarkable fact that in several cases, when 

 the paraiodtoluol was not perfectly pure, the liberation of iodine in 

 considerable quantity was observed during the bromiring; but, in spite 

 of this, the product contained paraiodbenzylbromide, thus apparently 



* Kurner, Bull. Acad. Roy. Belg. [2], 24, p. 157. 

 t V. Meyer, Ber. D. Ch. G., 1875, p. lOl-i, note. 



