IOWA ACADEMY OF SCIENCES. 95 



(Lehrbucb, p. 713)) afterwards made a further study of the 

 compound and assigned it to the formula C,oH,„0. Rudolph 

 Fittig (Ann. 125, 328), in 1863, prepared from the; above 

 mentioned distillate by means of sulphuric acid a com- 

 pound which he called diphenyl and assigned the form- 

 ula, CHj.CoHs and made the supposition that the reaction 

 took place according to the following equation: 



0-|-2H,S0, -CeH,. H,SA+(aH,).-h2 H,0. 



Kekule (Lehrbuch. Vol. Ill, 19), opposed the formula of 

 List and Limpricht on the ground of Fittig's work, 

 and argued that it must be monohydroxy diphenyl 

 (HO.CeHj.CsHs), which would have the same empyrical' 

 formula. 



C. Lesimple in 1867 (Ann. 138, 375), prepared a substance 

 by distilling tryphenyl phosphate with an excess of lime, 

 which he called phenyl oxide, although his analysis shows 

 that the per cent of hydrogen was .9 too low. The melt- 

 ing point also was 53' too high, but this he could not have 

 known, as List and Limpricht's compound remained a 

 liquid. (This was afterwards shown by Hoffmeister to be 

 due to impurities.) 



In view of all the uncertainty that existed, W. Hoffmeister 

 in 1871 (Ann. 151, 191), set out to determine whether diphe- 

 nyl ether had really been prepared or not. He repeated 

 the experiments of List and Limpricht, but distilled off the 

 compound in question from the phenyl benzoate with 

 steam instead of separating by fractional distillation, and 

 thus obtained the substance in a much purer state. It was 

 then a crystalline solid, and had a melting point of 27' C. 

 He showed that diphenyl could not be obtained from this 

 crystalline compound by the action of sulphuric acid, but 

 that it occurred as an impurity when diphenyl ether was 

 made by the method of List and Limpricht, and Fittig 

 had simply separated it. Kekule was therefore wrong 

 with regard to the constitution of the compound. He also 



