20 REPORT — 1859. 



CH 3 Na+C0 2 = C 2 H'Na0 2 

 Sodium-methyl. Acetate of sodium. 



(B) The supposed formation of methyl compounds from acetone* ; e.g. — 



C 3 H°0 + = C 3 H G 2 



Acetone. Acetate of methyl. 



(C) The formation of complex hydrocarbons (ethylene, propylene, amy- 

 lene, benzine, naphtaline, &c, by the action of heat on organic substances of 

 simpler constitution. Synthesis of organic compounds) f, 



III. Isologous transformations. 



(A) The conversion of glycerine into iodopropylene, and of the latter into 



allylic alcohol % : — 



2(C 3 H 5 I) + Ag 2 C 2 4 = 2AgI + (C 3 H 5 ) 2 C 2 4 

 Iodopropylene. Oxalate of Oxalate of allyl. 



silver. 



(C 3 H 5 ) 2 C 2 4 + 2NH 3 = 2C 3 H 6 + C 2 H 4 N 2 2 

 Oxalate of allyl. Allylic Oxamide. 



alcohol. 



(B) The production of cinnamic aldehyde from acetic and benzoic alde- 

 hydes! : — 



C 2 H 4 + C 7 H c O=C s H 8 + H 2 



Acetic aide- Benzoic Cinnamic 

 hyde. aldehyde, aldehyde. 



(C) The production of cinnamic acid from chloride of acetyl and benzoic 

 aldehyde || : — 



C 2 H 3 0C1 + C 7 H 6 0=C°H 8 2 + HC1. 



Chloracetyl. Benzoic Cinnamic 

 aldehyde. acid. 



Throughout the foregoing Report Gerhardt's atomic weights have been 

 used without discussion ; for it seemed superfluous to enumerate once more 

 the reasons for adopting them, which, as the science advances, become more 

 and more numerous and conclusive^]". It may, however, be expected that 

 some notice should be taken of such objections as have been recently made 

 against this system. 



Within the last few years three different chemists have, for very different 

 reasons, proposed to modify Gerhardt's atomic weights, but they all agree in 

 adopting the doubled atomic weight of carbon, while they reject the doubled 



* Friedel, Ann. Chem. Pharm. cvii. 174 ; cviii. 388. 



t Berthelot, Ann. Chim. Phys. [3] liii. 69. 



X Hofmann and Cahours, Chem. Soc. Quart. Journ. x. 316; Ann. Chem. Pharm. cii. 285 ; 

 Ann. Chim. Phys. [3] 1. 432. 



§ Chiozza, Ann. Chem. Pharm. xcvii. 350. 



|| Bertagnini, Ann. Chim. Phys. [3] xlix. 376. 



*H Some recent experiments nevertheless tend to show that the atomic weights assigned 

 hy Gerhardt to some of the metals ought to he doubled. For instance, the vapour-density 

 of zinc-ethyl (Frankland, Ann. Chem. Pharm. xcv.), the way in which zinc combines with 

 iodide of ethyl (similar to the combination of oxygen with zinc-ethyl, Zn 2 -(-C 2 H 5 I = C 2 H 5 

 Zn 2 I, and 0-|-C 2 H 5 Zn = C 2 H'OZn), the vapour-density of mercury-methyl and of mer- 

 cury-ethyl (Buckton, Proc. Roy. Soc. ix. 92, 311), and the combination of mercury with 

 • iodide of ethyl (forming C 2 H 5 Hg 2 1), seem to show that the atomic weights of zinc and mer- 

 cury are twice as great as they were adopted by Gerhardt. Similar reasons may be urged in 

 favour of doubling the atomic weight of tin, as recommended some time since by Odling 

 (Phil. Mag. [4] xiii. 434). As these points, however, belong to inorganic chemistry, we 

 cannot do more than simply refer to them here. 



