1868 The complete Practical Distiller

THE COMPLETE PRACTICAL DISTILLER.

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quantity of water of fixed temperature passing through the cooler in a given time. It is necessary that the fire should be regulated in such a manner that the quantity of vapour produced should be neither greater nor less than that which at the same time may be condensed by the application of cold. The failure of attention to this circumstance (particu- larly in the distillation of spirituous liquors) may pro- duce the following inconveniences : — First, if the fire is too violent, a great quantity of the condensed vapours will pass from the worm into the external air, and occa- sion the loss of the matter distilled, and also of the fuel. Secondly, if the fire or heat is diminished too soon, the condensation will produce a vacuum in the worm and in the alembic, which, not being proportionably filled by the fresh vapour, will admit the entrance of the external air, and impede both operations ; and, lastly, will carry with it a part of the vapours, and occasion loss of time, and also of the matter distilled. To remedy these defects, and at the same time provide simple and eflPectual means for indicating the exact state of the heat every instant, an instrument has been invented which may be adapted to any distillery or apparatus, and is, in reality, nothing more than an application of known and practical princi- namely, that in intercepting the communica- tion of the atmospheric air, the products of the distillation are more abundant and perfect; for, in proportion as the vapours condense, a vacuum is formed in that part of the apparatus into which the vapours are drawn, in the same manner as by the pump : they are also less compressed ples. This ingenious machine possesses another singular advantage ;