Leaving this column, the vapours are conducted into a horizontal cylinder E, containing a coil S, Fig. 181, which lies in a hot liquid. This liquid is the liquor_ which has to be distilled.
Entering by the pipe t, Fig. 181, it is distributed over holes in the plate y y, and, falling in drops into the oylinder, is heated by contact with the coil S. The cylinder is divided into two compartmeuts by a diaphragm which is pierced with holes at its lower extremity ; through these holes the liquor flows into the second compartment, and passes out at the top, where it runs through the pipe a, into the top of the column C.
The vapours are made to traverse the coil S, which is kept at an aver age temperature of 50° in the right hand compartment and somewhat higher in the other. They pass first through J into the hottest part of the coil, and there give up much of the water with which they are mixed, and the process of concen tration continues as they pass through the coil. Each spiral is connected at the bottom with a ver tical pipe by which the condensed liquors are run off; these are con ducted into the pipe P P. Those which are condensed in the hottest part of the coil, and are conse quently the weakest, are led by the pipe L into the third vessel in the column D, Fig. 180, while the stronger portions pass through L' into the fifth. The stop-cocks a o regulate the flow of liquid into these vessels, and consequently also the strength of the spirit obtained.
Lastly, as they leave the cylinder, the highly concentrated vapours are condensed in the vessel F, which contains another coil. This is kept cool by a stream of liquor flowing from the reservoir Il into the smaller cistern G, from whioh a continuous and regular flow is kept np through the tap o into the funnel tube S, and thence into the condenser F ; it ultimately flows into the cylindor E through the pipe t, there being no other outlet. The finished products run out by the pipe s iuto suitable lereivers.
A wpm', mom WI/tr.—The most important of the many sources from which alcohol is obtained on an industrial scale, is wine. Tho distillation of alcohol from wines is confined exclusively to France, where the best wines for this purpose are prepared. Tho spirit obtained from them is used very extensively in thc same country for the production of all kinds of brandy. As the wines
employed are generally of special preparation and must be chosen with much care, we shall here devote a little space to tho details of their preparation from the grape, as carried on in France.
Of all the fruits employed as sourc,es of alcohol, the grape must occupy the first place. Not only does it present the advantage of containing in itself the sugar, the water, and the ferment necessary for the conduct of the fermenting process, but tho spirit which it yields is unequalled for fineness, bouquet, or delicacy of aroma. The grapee should bo just ripe when gathered, a period recognized by the softening of the fruit, the brownness of the stem, and the sweetness and stickiness of the expressed juice. Much care is requisite in the performance of cutting, in order t,o avoid bruising the fruit ; this should be performed with shears or scissors, uot with a knife.
The next operation is the crushing, the object of which is to mix up and to bring iato contact with each other all the constituent elements of the grape. If this be not done, it withers and dries up without undergoing the necessary fermentation. It may be conducted advantageously in a square box, open at the top and with holes pierced in the bottom ; this box is fixed upon the edges of the vat. Inside it, tho fruit ie trampled under foot by a man wearing wooden boots, and the juice pressed out flows through the perforated bottom of the box into the vat ; this is continued until the vat is full. The refuse, or marc, as it is called, may either ha fermented in the vat with tho juice, or in a separate vessel. This plan is much to be preferr( d to flint of crushing the grapes in tho vat, as, in the latter case, much of the fruit floats about in the must untouched, and thus escapes fermentation. It is nn advantage not to stem the grapes before crushing, as the presence of tho sterns in the vat promotes and regulates tho fermentation ; moreover, they contain an astrin gent principle, which assists in preserving wines containing but little alcohol. Sufficient room must bo loft in the vat to allow for the increase in volume undergone by its contents, in consequenco of the elevation of temperature resulting from the fermentation.