534 Royal Society : — 



3. The electric capacity of a conducting bodj^— that is, the_ quan- 

 tity of electricity which it acquires when placed in communication 

 with a source of electricity — is much greater when the body is 

 surrounded with sulphur, or some other solid isolating substance, 

 than when surrounded by air. Similarly, the body being electrified 

 from the same source and then surrounded with sulphur, or else 

 surrounded with air, afterwards yields to the same conductor much 

 less electricity in the former case than in the latter. 



4. The effects produced by insulathig plates interposed between 

 the armatures of a Leydcn jar or of a magic square are explained, 

 together with the phenomena previously described, both by the 

 penetration of the electricity into the interior of the insulating sub- 

 stance, and the propagation of electricity along the surface of the 

 plates. 



" On the Synthesis of Acetic Acid." By J. A. Wanklyn, Esq. 



I have elsewhere* shown that a salt of propionic acid results 

 when carbonic acid is brought into contact with a compound consist- 

 ing of ethyle and an alkali-metal. Guided by a well-known principle, 

 I also inferred that an analogous reaction is common to the whole 

 vinic series. 



Believing, however, that it was desirable to investigate other mem- 

 bers of the series, I have since undertaken the case of the corre- 

 sponding methyle-compound, and find that it fully bears out the law, 

 as will be manifest from the following details. 



Some sodium-methyle in mixture with zinc-methyle, zinc, sodium, 

 and ether was obtained by acting with sodium upon a strong ethereal 

 solution of zinc-methyle. The product so obtained was divided into 

 two portions — one of which was exposed to the action of a current 

 of dry carbonic acid, and the other reserved for comparison. 



During the transmission of carbonic acid, the sodium-methyle 

 became hot. After the completion of the reaction, the resulting 

 solid was treated with a little mercury, in order to convert any free 

 sodium into an amalgam, which would not decompose water with too 

 great violence. 



Subsequent distillation of the product, with excess of dilute sul- 

 phuric acid, yielded a distillate having most distinctly the smell and 

 taste of acetic acid. This acid distillate was redistilled, when it 

 proved to be free from sulphuric acid. 



Some of it was converted into a silver-salt by digestion with oxide 

 of silver. This silver-salt was dissolved in hot water, filtered hot, 

 and allowed to crystallize on cooling. An abundant crop of crystals 

 separated, which was drained from the mother-liquor, the employ- 

 ment of a filter being avoided. The crystals were afterwards dried 

 in vacuo over sulphuric acid until they no longer lost weight. 



Determinations of silver were made by ignition, the resulting silver 

 being reheated and reweighed until it remained constant. 



T. '0894 gramme of the salt gave "0580 gramme of metallic silver. 



TI. '1.597 gramme of thesalt gave '1022 gramme of metallic silver. 

 * See Quarterly Journal of the Chemical Society, July 1858, page 130. 



