610 



FARMERS' REGISTER. 



[No, 11 



In the manufacture of ale and porter, the sugar 

 formed during the germination of barley is made 

 to ferment by dissolving it in water with a little 

 yeast, which contains gluten in the state proper 

 for producing fermentation, and exposing it to the 

 requisite temperature; carbonic acid gas is given 

 off as in the /ermentation of must, and the liquor 

 gradually becomes spirituous. 



Similar phenomena occur in the fermentation 

 of the sugar in the juice of apples and other ripe 

 fruits. It appears that fermentation depends en- 

 tirely upon a new arrangement ot' the elements of 

 sugar ; part ofthe carbon uniting to oxygen to Ibrra 

 carbonic acid, and the remaining carbon, hydrogen, 

 and oxygen combining as alcohol; and the use ofthe 

 gluten or yeast, and the primary exposure to air, 

 seems to be to occasion the formation of a certain 

 quantity of carbonic acid ; and this change being 

 once produced iscontinHed;i(sagency may be com- 

 pared to thatof aspark in producingthe inflamma- 

 tion of gunpowder; the increase of temperature 

 occasioned by the formation of one quantity of 

 carbonic acid occasions the combination ofthe ele- 

 ments of another quantity. 



From the experiments of M. Theodore de Saus- 

 sure it appears that alcohol is composed of 100 

 parts of olefiant (or percarbu retted hydrogen Tas), 

 and of 63.58 water, or oxygen and hydrogen in 

 the proportions necessary to form water. 



Alcohol, in its purest known form, is a highly 

 inflammable liquid, of specific gravity 796, afthe 

 temperature of 60°; it boils at about 170^ Fah- 

 renheit. This alcohol is obtained by repeated dis- 

 tillation of the strongest common spirit from the 

 ealt called by chemists muriate of lime, it havino- 

 been previously heated red hot. 



The strongest alcohol obtained by the distilla- 

 tion of spirit without salts has seldom a less spe- 

 cific gravity than 825 at 60*^ ; and it contains^ ac- 

 cording to Lowitz's experiments, 89 pans of the 

 alcohol of 796, and 11 parts of water. The spirit 

 established as proof spirit by act of parliament 

 passed in 1762 ought to have the specific gravity 

 of 916 ; and this contains nearly equal weights of 

 pure alcohol and wafer. 



The alcohol in fermented liquors is in combina- 

 tion with water, coloring matter, suirar, muci- 

 lage, and the vegetable acids. It has^'been often 

 doubted whether it can be procured by any other 

 process than distillation ; and some persons have 

 even supposed that it is formed by distillation. 

 The experiments of Mr. Brands are conclusive 

 against both these opinions. That gentleman has 

 shown that the coloring and acid matter in wines 

 may be, for the most part, separated in a solid 

 form by the action of a solution of sugar of lead 

 (acetate of lead,) and that the alcohol may be 

 then obtained by abstracting the water by means 

 of hydrate of potassa or muriate of lime, without 

 artificial heat. 



The intoxicating powers of fermented liquors 

 depend on the alcohol that they contain ; but their 

 action on the stomach is modified by the acid, sac- 

 charine, or mucilaginous substances they hold in 

 soluiion. Alcohol probably acts with most effica- 

 cy when it is most loosely combined ; and its en- 

 ergy seems to be impaired by union with large 

 quantities of water, or with sugar or acid, or ex- 

 tractive matter. 



The table in the following page contains the 

 results of Mr. Brande's experiments on the quan- 



tify of alcohol of 825 at 60", in diflerent ferment- 

 ed liquors. 



The spirits distilled from different fermented li- 

 quors differ in their flavor: for peculiar odorous 

 matter, or volatile oils, rise in most cases with the 

 alcohol. The spirit Irom malt usually has an em- 

 pyreumatic taste like that of tlie oil, formed by 

 the distillation of vegetable substances. The best 

 brandies seem to owe their flavor to a peculiar 

 oily matter, formed probably by the action of the 

 tartaric acid on alcohol ; and rum derives its cha- 

 racteristic taste from a principle in the sugar cane. 

 All the common spirits may, I find, be deprived of 

 their peculiar flavour by repeatedly digesting them 

 with a mixture of well-burnt charcoal and quick- 

 lime ; they then afford pure alcohol by distillation. 

 The cognac brandies, I find, contain vegetable 

 prussic acid, and their flavour may be imitated by 

 adding to a solution of alcohol in water of the 

 same strength, a few drops of the ethereal oil of 

 wine produced during the formation of ether, * 

 and a similar quantity of vegetable prussic acid 

 procured from laurel leaves or any bitter kernels. 



I have mentioned clher in the course of this 

 Lecture; this substance is procured from alcohol 

 by distilling a mixture of equal parts of alcohol 

 and sulphuric acid. It is the lightest known liquid 

 substance, being of specific gravity 632 at 60^*. 

 It is very volatile and rises in vapor, even by the 

 heat of the body. It is highly inflammable. In 

 the formation of ether it is most probable, from 

 the experiments of M. de Saussure, that the ele- 

 ments of water merely are separated from the al- 

 cohol by the sulphuric acid, and that ether differs 

 from alcohol in containinsr a larger proportion of 

 carbon and hydrogen. Like alcohol, it possesses 

 intoxicating powers. 



A number of the changes taking place in the 

 vegetable principles depend apon the separation of 

 oxygen and hydrogen as water from the com- 

 pound ; but there is one of very great importance, 

 in which a new combination of the elements of 

 water is the principal operation. This is in the 

 manufacture of bread. When any kind of flour, 

 which consists principally of starch, is made into 

 a paste with water, and immediately and gradu- 

 ally heated to about 440°, it increases in weight, 

 and is found entirely altered in its properties ; it 

 has lost its solubility in water, and its power of 

 being converted into sugar. In this state it \& 

 unleavened bread. 



When the flour of corn or the starch of pota- 

 toes, mixed with boiled potatoes, is made into a 

 paste with water, kept warm, and suffered to re- 

 main 30 or 40 hours, it ferments, carbonic acid gas 

 is disengaged from it, and it becomes filled with 

 globules of elastic fluid. In this state it is raised 

 dough, and aflbrds, by baking, leavened bread ; 

 but this bread is sour and disagreeable to the taste; 

 and leavened bread for use is made by mixing a 

 little dough, that has fermented, with new dough, 

 and kneading them together, or by kneading the 

 bread with a small quantity of yeast. 



In the formation of wheaten bread, more than 

 one quarter of the elements of water combine 



* In the process of the distillation of alcohol and 

 sulphuric acid after the ether is procured ; by a higher 

 degree of heat, a yellow fluid is produced ; which is 

 the substance in question. It has a fragrant smell and 

 an agreeable taste. 



