File:Conversations on chemistry - in which the elements of that science are familiarly explained and illustrated by experiments - to which are now added explanations of the text, questions for exercise, (14591064898).jpg

Identifier: 0205323.nlm.nih.gov
Title: Conversations on chemistry : in which the elements of that science are familiarly explained and illustrated by experiments : to which are now added explanations of the text, questions for exercise, directions for simplifying the apparatus and a vocabulary of terms, together with a list of interesting experiments
Year: 1824 (1820s)
Authors: Comstock, J. L. (John Lee), 1789-1858
Subjects: Chemical Phenomena
Publisher: Hartford : Cooke
Contributing Library: U.S. National Library of Medicine
Digitizing Sponsor: Open Knowledge Commons, U.S. National Library of Medicine

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ent qualities ofthe fruits,from which they are obtained, independently ofthe sugar. Caroline. I am astonished to hear that so powerful a li-quid as spirit of wine should be obtained from so mild a sub-stance as sugar. Mrs. B. Can you tell me in what the principal differenceconsists between alcohol and sugar ? Caroline. Let me reflect;—Sugar consists of carbon, hy-drogen, and oxygen. If carbonic acid be subtracted from it,during the formation of alcohol, the latter will contain lesscarbon and oxygen than sugar does ; therefore hydrogenmust be the prevailing principle of alcohol. Mrs. B. It is exactly so. And this very large proportionof hydrogen accounts for the lightness and combustible pro-perty of alcohol, and of spirits in general, all of which consistof alcohol variously modified, Emily. And can sugar be recomposed from the combina-tion of alcohol and cf.rbonic acid ? Mrs. B. Chemists have never been able to succeed ineffecting this ; but from analogy I should suppose such a re-
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« ©S VEGETABLES. 275 composition possible. , Let us now observe more particularly,tbe phenomena that takes place during the vinous fermenta-tion. At the commencement of this process, heat is evolved,and the liquor swells considerably from the formation of thecarbonic acid, which is disengaged in such prodigious quan-tities as would be fatal to any person who should unawaresinspire it ; an accident which has sometimes happened. Ifthe fermentation be stopped by putting the liquor into barrels,before the whole of the carbonic acid is evolved, the wine isbrisk, like Champagne, from the carbonic acid imprisoned init, and it tastes sweet, like cider, from the sugar not beingcompletely decomposed. Emily. Hut I do not understand why heat should be evol-ved during this operation. For, as there is a considerableformation of gas, in which a proportionable quantity of heatmust become insensible, I should have imagined that cold,rather than heat, would have been produced. Mrs. B. It appears so o

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