316 "Royal Society. 



has recourse to the ultimate analysis of the charcoal obtained from, 

 alcohol and olefiant gas, a mode of experimenting which he con- 

 ceives is less liable to error. 



He states that the views thus sought to be established are con- 

 firmed, not merely by these direct experiments, but likewise by other 

 changes which fermented liquors undergo on being kept under cir- 

 cumstances favourable for further chemical action ; and that having 

 proved the existence of such a compound as one constituted of car- 

 bon, hydrogen and nitrogen, and shown that water is decomposed 

 during its formation, he thinks we are enabled to account for many 

 other changes which occur during the decomposition of vegetable 

 matter and the growth of plants : whence he proceeds to show that 

 evidence of the presence of such a compound as the above in fer- 

 mented liquors is afforded by the changes which take place in con- 

 sequence of keeping them. 



On subjecting to ultimate analysis the semi-fluids obtained by ex- 

 posing fermented liquors to a temperature of 110° Fahr., the author 

 found a decided difference between the chemical constitution of 

 those procured from old, and those from new vinous fluids ; and on 

 searching for the law by which these differences are regulated, he 

 found that the spirituous part entered into such combination with 

 the excess of oxygen before referred to, and the undecomposed ve- 

 getable matter, so as to form with them new compounds. 



After experiencing some difficulty in effecting a separation of 

 these newly formed bodies, he found that while rectified pyroxylic 

 spirit, of the specific gravity from 830 to 835, scarcely dissolved an 

 appreciable quantity of the extract of malt and hops, considerable 

 portions of the semi-fluids obtained from old ale and old porter were, 

 by agitating, dissolved therein. By using this spirit as a solvent he 

 effected such a separation as enabled him to discover decided differ- 

 ences between the proximate chemical constitution of the semi- 

 fluids obtained from old ale and old porter, and those from liquors 

 of the same description when new. 



In accounting for many of the phenomena which accompany 

 the vinous fermentation, the author observes that the small excess 

 of oxygen found in all these compounds, which undergo this chemi- 

 cal action, is an essential and indispensable circumstance ; a con- 

 clusion which is corroborated both by the formation of these new 

 compounds which have been described, and by the generation of the 

 acetic, tartaric, or malic acid, which is found in fermented liquors at 

 all times, and in quantities varying according to the situations un- 

 der which these fluids have been kept. 



June 13. — The following papers were read, viz.: — 



" Researches on the Tides. Tenth Series. On the Laws of Low 

 Water at the Port of Plymouth, and on the permanency of mean 

 water." By the Rev. W. Whewell, B.D., F.R.S., Fellow of Tri- 

 nity College, Cambridge*. 



* The former series of Prof. Whewell' s Researches on the Tides have 

 already been noticed in our pages. See Lond. and Edinb. Phil. Mag., vol. 

 xii. p. 54 note; and vol. xiii. p. 457. 



