4-09 



ascertained to yield one fifth part of alcohol by distillation. When 

 the same experiment was repeated on the same wine, to which one 

 seventh part of alcohol had been previously added, still none was 

 separated by subcarbonate of potash : but when so much as one 

 third part had been added, then a very small proportion was found 

 to float upon the surface after it had stood twenty-four hours. 



When madeira or sherry were employed instead of port, the re- 

 sults were nearly the same. Since the method of Fabroni failed of 

 detecting the presence of alcohol, unless the quantity was very con- 

 siderable, it became necessary to have recourse to some other method 

 of proving or disproving the presence of it as a product of fermenta- 

 tion ; and Mr. Brande conceived, that if it were formed by the heat 

 applied in distillation, the quantity should in that case be different 

 when the same liquor was distilled at different temperatures. 



In the first of four processes of distillation, port wine was made to 

 acquire the heat of 200 by addition of muriate of lime, and one half 

 was quickly distilled over ; and in the last, an equal quantity of port 

 was kept for five days at the temperature of 180, till half the quan- 

 tity had passed over into the receiver ; but in all these experiments 

 the specific gravities of the products were so nearly the same, that 

 there did not appear to be any difference in the quantity of alcohol 

 obtained. 



Mr. Brande also attempted to separate alcohol from different kinds 

 of wine by freezing ; but the cake of ice produced was spongy, and 

 would not allow any portion of alcohol to separate from it. 



The author having thus, to his satisfaction, proved the existence 

 of alcohol ready formed in fermented liquors, undertook, in the next 

 place, to ascertain the relative strength of different kinds of wine ; 

 and he concludes the present communication with a Table, in which 

 is expressed the proportion per cent, of alcohol contained in a given 

 measure of the several liquors that he has examined. 



In this table the alcohol obtained from Port varies from 21 to nearly 

 26 per cent.; Madeira 19 to 24; Sherry not so much as 20 per cent.; 

 Claret from 13 to 16; Lisbon 19; Marsala nearly 26; Champagne 

 from 11 to 13; Burgundy 12 to 14; Hock 9 to 14; Raisin wine 25^; 

 Currant wine 20^ ; Cider and Perry nearly 10; Ale nearly 9 per cent. ; 

 good rum and brandy containing 53 per cent, of alcohol at the same 

 standard of '825 specific gravity. 



Account of a Lithological Survey of Schehallien, made in order to de- 

 termine the specific Gravity of the Rocks which compose that Moun- 

 tain. By John Playfair, Esq. F.R.S. Read June 27, 1811. [Phil. 

 Trans. 181 1,^.347.] 



Norwithstanding the skill with which Dr. Maskelyne conducted 

 the astronomical observations upon Schehallien, and the accuracy 

 with which he may be presumed to have measured the deflection of 

 his plumb-line from the perpendicular, whereby he discovered the 

 actual attraction of that mountain ; and although great ingenuity 



