1868 The complete Practical Distiller

THE COMPLETE PRACTICAL DISTILLER.

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that IS; when weighing 152° — passes into vapour at 172® temperature. Its vapour possesses the same temperature, and contains much less heat than the vapour of water ; for two pounds of alcoholic vapour, mixed with about six of cold water, will only give a mixture of alcohol and water of 172° heat. Vapour of water, which can only remain vapour at 212° of temperature, will be condensed at a temperature at which alcohol will keep its vaporous state : in water, for instance, of 172° temperature, the vapour of water will be condensed, when, at the same time, that of alco- hol will pass through it without undergoing the least condensation. If, instead of passing through water at 172°, this vapour passed through boiling wine, the water will be condensed in favour of the alcohol of the wine, which will be vapor- ized in relative proportions, and this in virtue of the well-recognised fact that when wine, composed of a mix- ture of alcohol and of water, is in a state of ebullition, alcohol only takes the temperature of 172°, which is, of course, colder tham that of water. What happens in this case ? The vapour of the water, in traversing the mixture, is condensed, because it meets with alcohol which has only 172° ; and as the latter cannot take any more heat without passing into vapour, it is vaporized by means of the heat which the steam of water has abandoned in being condensed. Supposing the vapour which passes through wine in a state of ebullition to be itself a mixture of vapours, of water, and of alcohol, it is easily foreseen what will hap- pen, — the portion of alcoholic vapour will pass without