MR. WATSON SMITH ON ISODINAPHTHYL. 25 



all of which has passed over, be again introduced into the 

 retort, and the same plan again proceeded with, this ob- 

 servation may be made successfully, as a small quantity 

 of high boiling substance carried over in the first distilla- 

 tion will be increased by a further accumulation in the 

 second, and an appreciable quantity will be left behind. 



A quantity of the pure substance crystallized from abso- 

 lute alcohol was taken for analysis. The following results 

 were obtained : — 



I. 0*1240 grm. of substance gave 0*4307 grain C0 2 "I 



0-0624 »■ H 2 J 

 II. 0-1237 „ „ „ 0-4284 „ C0 2 



0*0626 ,, H 2 



I. II. Calculated for ^og 7 1 



_*-, _^ _^ ^io-H-tJ 



Carbon 94*72 94'4^ 94'49 



Hydrogen 5-59 5-62 5-51 



100-31 IOO"08 IOO'OO 



A calculation may also be made from the weight of 

 hydrogen given off in the reaction in the hot tube ; and I 

 think it is well worthy of notice, as it was this observation 

 which first led me to think the reaction must be as 

 follows, viz. :- 2Cio h 8 = C io H 7 j +2R 



Weight of naphthalin converted =26*3 grms. (about). 

 Volume of hydrogen at o° C. evolved =2363 cub. cents. 



Then — ^— ^-=0*2109 grm. hydrogen actually obtained. 

 1 1200 



256 2 



2C 10 H 8 lose H 2 .'. 26-3 lose 0-2055 ,, ,, calculated. 



Difference 0-0054 



For the formula 



7C 10 H 8 = 5C 14 II 10 -j-6II, 0-1861 ,, „ should be liberated. 



Conclusions. 



I find from the foregoing facts : — 



1st. That whereas Berthelot found that diphenyl 



