IOWA ACADEMY OF SCIENCES. 
95 
(Lehrbuch, p. 7 IB), afterwards made a farther study of the 
compound and assigned it to the formula C I2 H 10 O. 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, C e H 5 .C 6 H 5 and made the supposition that the reaction 
took place according to the following equation: 
C 0 H 5 
l- 
0+2H;S0 4 =C 1> Hs. H 2 S 2 0 8 +(C 6 H 5 ),+2 h 2 o. 
C.H. 
Kekule (Lehrbuch. Yol. 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,C 6 H 5 .C 6 H 5 ), 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 w T as 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 tho 
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 
