HARVARD COLLEGE LIBRARY FROM THE WEIRS OF GEORGE C. DEMPSEY LONDON: REED AND PARDON, PRINTERS, PATERNOSTER ROW. BHS The Heirs of George C. Dempsey AUTHOR'S PREFACE. ALTHOUGH the liquor which Noah prepared from the juice of the grape has been made the subject of numberless examinations, the announcement of a new investigation of it can hardly astonish any one; for, in the first place, there are certain matters in every kind of wine, of which neither the quantity nor the quality are yet determined; and until these are investigated, the examination of wine will not be completed. Moreover, the almost unlimited variety which is peculiar to wine, and depends entirely upon variations in the constituents of the wine, has never been traced back to its cause; and further, many methods of determining even the most ordinary vinous ingredients are still imperfect, and must be replaced by others. Lastly, there are many adulterations practised upon wine, which keep pace with the extension of chemical knowledge, and which have been as yet by no means sufficiently explained. If it be admitted that it is useful to make public, to compare, and to test the most important results A 2 obtained from the examination of this fluid, and the various methods which have been employed in order to obtain such results, then it can surprise no one that such a general chemical investigation of wine as the present state of science renders possible, should be undertaken. So far, then, from apologising for subjecting the juice of the grape to a closer investigation, I shall have to beg the indulgence of the reader for still leaving room for so much more work upon wine. One especial deficiency will remain, in the want of acquaintance with the particular components of very many kinds of wine, which in colour, smell, and taste present an almost endless variety. And I may say, that even this treatise will tell but little in comparison to what will eventually be known about wine, for it only lays claim to be looked upon as a step in advance. Although not inhabiting a wine country, I have had abundant opportunity during the years which I have devoted to science of examining this liquid, and have always tasted it thankfully, and prized it very highly both for myself and others. I have always followed attentively the progress of our knowledge of wine, and I have frequently been asked to give advice in cases where adulteration was supposed to exist, so that I have gone over the whole subject with especial interest. Nothing would have been easier than to put into this treatise a summary of the natural history of different wines, or to have written diffusely and in detail about their preparation; but I have forborne to do either, simply on the ground that I could have added nothing on these subjects to that which is already known. Those who wish to acquaint themselves with the natural history of wine can have no better assistant than Henderson, History of Ancient and Modern Wine, (London ;) which contains a store of observations upon the most important kinds of wine: also, Jullien, Topographie de tous les Vignobles connus, Paris, 1814. Upon the preparation of wine they can consult Chaptal, L'Art de faire le Vin, Paris, 1810, 2nd edition; Ritter, Weinlehre, Mainz, 1817; Balling, Gährungschemie, Prag. 1845; and also some works which will be referred to several times in the course of this treatise; namely, Fauré, Batilliat, and Von Babo's work on Die Erzeugung und Behandlung des Traubenweins, Frankfurt a. M. 1846; and Bronner, Die Bereitung der Rothweine, Frankfurt a. M. 1855. A few words upon the fermentation of the grapejuice are prefixed as an introduction to the chemical knowledge of wine, and this has been done in order to trace the origin of the constituents of the wine. I was obliged to begin with grape-juice, and explain the alterations it undergoes during the vinous fermentation, in order to be able thoroughly to treat of the components of wine. And yet this treatise cannot claim to be called, "A Chemical Monograph on Wine;" first, because it does not treat of the preparation of wine: and, secondly, because there are in it far too many deficiencies, which, however, cannot immediately be supplied. A chemical monograph on wine is at present impossible; in any age a single life would be insufficient for such a work. I have endeavoured to bring together as faithfully as possible what has been chemically determined and recorded by others on this subject, and to extend, complete, or at least prove the same by my own observations, and in this manner to prepare the ground, and render such a chemical monograph possible at a later period, when the knowledge of those who come after us shall yield riper fruits than those which we are permitted to pluck. For the rest, I trust it may fare with the contents of this treatise, as Raymond Tully writes in his "Testamentum Novissimum," on the preparation of alcohol in the 13th century: "Destilla totam aquam ardentem in balneo; illam rectificabis, donec sine phlegmate sit." In conclusion, I beg leave to express my sincere thanks to Messrs. Vlaanderen, Oudemans, and Gunning, for the assistance they have rendered me in this investigation. UTRECHT. |