Volume 1

Chemistry, theoretical, practical, and analytical : as applied and relating to the arts and manufactures / by Dr. Sheridan Muspratt.

  • Muspratt, Sheridan, 1821-1871.
Date:
[1860]
Catalogue details

Licence: Public Domain Mark

Credit: Chemistry, theoretical, practical, and analytical : as applied and relating to the arts and manufactures / by Dr. Sheridan Muspratt. Source: Wellcome Collection.

    90/308 (page 74)
    of stills have been various. Previous to the year 1788, the old form of stiU was in general use. From the slow- ness of the distillation, a week elapsed before a charge was completely worked off, and even then the pro- ducts were very dilute. At this period the Excise duty ; levied was according to the size of the still, and no fur- ther trouble was taken by the officers as to how the I worts were made, except that they visited the distilleries ! occasionally, to observe if any other stills were in opera- tion, or if larger ones were substituted for those which had been already gaged. About the above period an important revolution took place in the construction of this apparatus by a firm in Leith, by which the distil- lation was very much expedited. They lessened the height and increased the width of the still, to expose a larger surface to the action of the fire than could be done in the old form; the head of the stiU was enlarged in proportion to the quantity of vapor gener- ated, and occasionally several outlets or pipes were inserted around the horizontal upper part, to facilitate the escape of the steam and alcoholic vapor into the condensing worm. This still could be charged, distilled off, and be ready for another operation, in the course of a few hours, instead of a week as before with the com- mon still. Though the inventors preserved to them- selves its exclusive use for about twelve months, yet such an important discovery could not escape the vigi- lance of competing neighbors, and hence it shortly after- wards became general in Scotland. The Excise, until they became apprised of the fact, were outwitted, the distillers, as might be expected, pocketing the duty which they otherwise shoidd have paid for the excess of spirits distilled above the ordinary allowance to which the former method of gaging subjected them. The Excise duty, however, was soon altered, and year after year it increased; but the distillers, constantly upon the alert, were enabled to hoodwink the overseers appointed by Parliament, which was driven to the necessity of nominating a committee, in 1799, to in vestigate this branch of the Excise laws, and wliich furnished a lengthy report of the facts concerning the modes of distillation in Scotland. In consequence of this report the distOlers were subjected to an Ex- cise duty according to the capacity of the still, and on the supposition that it would be worked off and charged every eight successive minutes dui-ing the dis- tilling season. Even this time was considerably short- ened by the distiller; still, the amount of fuel consumed, and the consequent wear and tear, left it a matter of doubt whether they were gainers by it. The rapidity of this method was carried so far, that, in 1815, the last year of the license duty, a still of eighty gallons capacity could be distilled off, emptied, and be ready for a successive operation in three and a half minutes, sometimes in three minutes! A still of forty gal- lons could be drawn off in two and a half minutes. An alteration in the Excise laws at this time did away with the license duty, and the law became the same as in England, of levying duty upon the wash and spirits procured therefrom, which dispensed with the rapid mode. In the meantime, the stills were constructed on the plan of those in use during the period of rapid distil- lation, namely, by having the bottoms wider than the English stills, in proportion to their size. From the interest which, at one time, was attached to the Scotch still, on account of the ingenuity displayed by the inventors, and its being a source of much inves- tigation to the Government committees, it may not be out of place to gratify the curiosity of the reader by introducing to his notice a drawing and brief description of the apparatus. As the general principles of the nature of the stiU have been already given, a recurrence to them is unnecessary. The subjoined Figs., 46 and 46“, represent a sectional and front view of the Scotch stU], at the period when Fig. 46. Fig. 46u. rapid distillation was popular amongst spirit manufac- turers. E E is the body of the stiU, the bottom of which is about sixteen feet in diameter, and convex towards the middle; the depth of the stiU at the centre is about eleven feet, and the sides and bottom meet at an acute angle at the verge. The hollow bottom of the StiU is connected with the shoulder, b, by solder, or rivets, but in so firm a manner that the connec - tion is air-tight; c, a rim, which serves to support the stiU, as likewise to protect it from the action of the