1868 The complete Practical Distiller

THE COMPLETE PRACTICAL DISTILLER.

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of B c, c D is four feet, and the capacity of the ba.l il is something more than that of the tube BCD. The distil- lation having commenced, the vapours condensed will pass through A and the ball H into the tube BCD. But it will only be when the two arms are filled that the liquor will go out through D to enter the vessel intended to re- ceive it. These two arms will then remain filled during the whole process of the distillation ; and in this consists the remedy of the inconveniences the instrument is in- tended to remove. It is easy to see, that if the fire becomes too brisk, the uncondensed vapour will not be able to discharge itself, by opening a passage to the external air, before having driven out all the liquor contained in the tube b c, and overcome the pressure of a column the height of which is equal to c D. In the second place, the external air cannot enter to occupy the void occasioned by the slow- ness of the fire, but only by expelling that from D C, and surmounting a pressure of the same height. Still, this column being four feet in height, allows a sufficient lati- tude and time for the workmen to regulate the fires. If the tube BCD was of glass, it would only be necessary to observe the level of the liquor in the two arms. Its being lowered in b c would indicate the necessity of diminishing the fire ; and in c D it would be necessary to increase it. But as the operation in the tubes of this length is rather precarious, it would be best to attach to E a little glass regulator E r E, of which the two arms E, F, each being three inches long, contains mercury ; this, in rising alternately in one or the other, would be an exact indication of the degree of the heat, and also of the vapours.