1868 The complete Practical Distiller

CONTINUOUS DISTILLATION.

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hol. when the spirit is required to be of great strength. This rectification is effected in the following way : The vapours condensed by the condenser Q I pass through the tube hj into the refrigerator, when they are sufficiently rich ; but, if this is not the case, they may, by means of the retrograding pipes g i and g j, be brought back, whole or only in part, to the rectifier; there they meet with obstacles in their fall similar to those opposed to the falling of wine in the column. These low wines undergo thus an analysis similar to that which the wine undergoes in the column ; that is to say, that these low wines arrive in the rectifiers much richer in alcohol than the wine that is worked, and that they leave this part of the apparatus in a state of rich- ness about equal to that of the vinous vapours. Thus it is evident that these low wines have been deprived of their alcohol in favour of the spirituous vapours by which they have been analyzed. It is thus that, by means of the rectifier and of the retrograding pipes, the strength of the spirits may be regulated. It has already been seen with what art and ingenuity this apparatus has been con- structed, and how successfully it fulfils the principles that have been established on the art of distillation. In fact, those vapours that are the most watery are always in contact with the weakest part of the wine ; and reci- procally, those that are charged with the greatest quantity of alcohol, when they are to be rendered richer, are always in contact with the richest liquid. Thus every thing con- curs to deprive the wine of its alcohol without ever ren- dering it richer itself, and to dephlegm the vapours without ever mixing them with liquids poorer in alcohol than 3*