decided preference over the open pans, commonly used in the West Indies and elsewhere. In the successive evaporations which the sirop undergoes, previous to the crystallizing process, the liquid is ladled from one vessel to another: in my apparatus this trouble is entirely dispensed with, the liquid continually running off, of itself. In the consumption of fuel, I conceive, there would be a considerable saving, as the caloric is applied with greater effect, and more economically, than by the usual furnaces; and the condensation of the vapour back into the sirop is prevented, by my external cone or covering, which excludes the evaporating surfaces from the air. My scrapers would also be applied very effectually in removing any incrustations that might form on the surface of the inner cone. cones might be made of any magnitude, or several might be arranged a little above one another.

The

For the generation of steam for motive engines, I see no difficulty in its application; for that purpose, the rapid and economical production of vapour in strong vessels appears to me all that is required. I need not repeat that my extended surface and mode of applying heat would produce vapour with great rapidity; and it is obvious that the conical form offers great strength. For low pressure steam, a very thin internal cone would do; and for high pressure, a very thick one would not be necessary; as the expansive force would be exerted in that direction where the vessel was strongest: the exterior cone should however be of greater strength than the interior one, yet of a less substance than boilers in ordinary use; and it would be attended with this further advantage, that in case of the exterior cone bursting, very little damage would result; there would be no hot water to scald, nor any masonry to be blown up, or building destroyed in consequence.

In the preparation of VINEGAR, it is a commonly received opinion, and I presume a correct one, that the acid property of the liquid is derived from its absorption of oxygen; the operation usually consists in exposing the liquid under fermentation, in open, or imperfectly closed, vessels, to the atmosphere. Now it has been found, that the oftener the surfaces of the liquid are changed, by agitation, or by Jadling or pumping it out of one vessel into another, the sooner the vinegar is formed. The acidifying principle being thus obtained, it appears to me to follow, that that apparatus must be the best for the purpose, by which the most extended surface of liquid can be conveniently exposed to the influence of the atmosphere; accordingly I venture to propose my cones, before described, for this purpose also, but under certain modifications. First, I would have made a series of cones (of the cheapest materials) and of such relative dimensions, that they may be enclosed concentrically one within another, a few inches apart: the liquid in the thinnest possible strata, might then be allowed to flow over them, by similar means to that described in the first part of my letter. The effect of this arrangement would I think be a very rapid absorption of oxygen, or in other words, the speedy forming of the vinegar. By the plan described, I have supposed the cones to be open at top and bottom, for the air to circulate between them. It might possibly be an improvement to let all these cones

terminate or open into one common tube; the air in which tube might be exhausted, by any convenient means, so as to increase the draft. An obvious and an inexpensive mode of producing this effect would be to supply the furnace with air for the combustion, from this tube, by which means a rapid current of air between the cones would be promoted. In vinegar manufactories a large furnace is almost always employed, whether in distilling the acid from wood, or in making a solution of malt.

VERDIGRIS, as is well known, is a combination of the acetic acid with the oxide of copper: it is usually prepared by frequently wetting the surfaces of copper plates with vinegar, by various media, and when the copper becomes sufficiently coated with the green oxide, it is scraped off, and put into bags for sale. This operation is usually performed by removing the copper plates, (which are about 12 inches square,) from the racks in which they are laid, and the plates are, one by one, scraped with an instrument made for the purpose. The copper plates used are generally very light, weighing about 16 ounces to the superficial foot; I would use copper of much greater thickness, in constructing my cones, and place several of them concentrically one within the other; each of the cones should be provided with a pair of scrapers, and the bevelled wheel and pinion before mentioned, so that I might act upon them all by the turning round of one spindle; thus the verdigris, covering several very extended surfaces, might be scraped off in a few seconds. The cones would last a considerable time, as the metallic portion of verdigris is but a small component part of it.

ENGLISH PATENTS.

Account and description of Evans's patent distilling apparatus.

WE shall introduce our description of Mr. Evans's New Apparatus, by which he proposes to remedy the defects of the old system, by inserting some observations made upon it, by the intelligent Editor of the Monthly Magazine, which appeared in July last; the invention is there announced in the following terms.

"Mr. Evans has constructed the model of a still, upon a new prineiple, which, if it answer on a large scale, will altogether supersede the old alembic. The theory of the machine is such, that it may, without hesitation, be pronounced the most decided improvement hitherto effected; for, if we mistake not, the still at present in use, remains in principle precisely the same, through the operation of the excise laws, that it was a century ago. Whatever improvements have been attempted, apply only to the rectification, while the first formation of the spirit is conducted in the same rude manner as in the infancy of science. We forbear entering into a more particular description, until the design be carried into execution upon a large scale. We should be extremely sorry, by premature publicity, to afford the continental distillers an opportunity of maintaining the superiority they have hitherto enjoyed, and we feel convinced, that

we shall now take the lead in this important branch of our produc tive industry. The new apparatus, eminently combines economy in practice, and simplicity in construction; but the most valuable attainment, is the production of pure untainted spirits, which may be drawn in one operation, at any point of strength.

We have made such a drawing of the apparatus, as to show the whole operation at one view; a is a pipe which conveys the wash' or fermented liquor into a reservoir b, where it is maintained at a certain level, by the ball valve c. d is the still, which is a revolving copper cylinder, with ledges fixed in horizontal lines against the inner surface, to increase the agitation of the wash, as it turns upon its hollow axis, fg: its motion is derived from the spur wheel h, acting upon the pinion i, fixed on the hollow axis f. j, is the rectifier; this is formed of a large pipe of uniform bore, coiled up into the spiral figure exhibited, with the ends bent, so as to form axes for rotation, on one of which, a pinion k (corresponding with that at i,) is fixed, and this pinion is acted upon by another spur wheel 1, on the same shaft as the other: m is the common distiller's refrigeratory, and n a receiver for the distilled spirit. The figure represented in dotted lines, is intended to show the position in which the still is drawn up, when it is necessary to cleanse it; for this purpose, there is at o, a universal joint of a peculiar construction, which enables it to be easily done, after having separated the connected tubes at the union joint, represented contiguous thereto.

The rectifier j, communicates with the still, through the hollow axle g, and with the refrigeratory, through a stuffing box; and the still communicates with the reservoir, by means of a syphon passing through the hollow axis f. The outward part of the syphon has two unequal limbs; the short limb inserted in the reservoir, is for the purpose of charging the still with the wash, and the long limb, for the purpose of discharging the spent liquor.

The operation is one of singular elegance, and our readers will, we doubt not, agree with us, that the novel and simple contrivances by which it is effected, evince a mechanical genius in the contriver, of no ordinary description.

In order to charge the still, the ball of the valve is pressed downward, so as to raise the liquid above the top of the syphon; this sets the syphon in action, and causes it to fill the still to the same level, as the liquid in the reservoir. Thus prepared, the fire is lighted, and a slow rotatory motion given to the still by the hand, or any other convenient first mover, applied to the shaft, upon which the spur wheels / and I are fixed. It matters not how fierce the fire may be, the continuous motion of the liquid prevents the formation of empyreuma, and those other ill effects incident to spirituous liquids in a fixed boiler. The agitation of the liquid in this vessel, and the intensity of the heat applied, cause a rapid production of vapour, which immediately enters the hollow axis g, and passes into the coiled worm of the rectifier j. It is here necessary to observe, that this capacious worm revolves in that direction pointed out by the arrow, consequently, whatever portion of the vapour becomes condensed in it,

runs out at every revolution, back through the hollow axis g, into the still; and the hollow axis g is, for this purpose, made tapering wider towards the still, so as to give the liquid a descent to run freely into it.

The vessel j is, therefore, properly termed a rectifier, as it sepa

rates the water from the diluted alcohol, before passing out of it into the refrigeratory m; in this, it arrives in a state more or less concentrated, according to the temperature preserved in the rectifier, which is regulated, as usual, by a thermometer; the spirit may, consequently, be drawn at one operation of almost any required strength. A very interesting feature in these new arrangements, is the mode of applying the syphon; which is constantly supplying the still with fresh wash, in place of that which has been vaporized, and this operation is uniformly continued during the rotation of the vessel, owing to its passing through a tubular axis: the syphon, in like manner, enables the still to be discharged without stopping the machinery. When it is necessary to re-charge the still with the fire under it, a thick cast-iron sliding plate is drawn from the back, so as to interpose itself between the fire and the still, and thus prevent any injurious effects to the contents of the latter. When fuel that does not emit much smoke, such as coke, or anthracite, is employed, the grate itself may be drawn out from under the still, by placing it upon castors, or rollers, and without inconvenience, as the time necessary to renew the operation of charging, sufficiently to prevent burning, is only the work of a few moments.

We shall here close our remarks, by acquainting our readers that this invention does not emanate from the wild speculations of a mere theorist; for Mr. Evans is an inquiring practical man; and his observations, and his experiments, have convinced him that alcohol is not altogether the result of the vinous fermentation, but the product of a subsequent elementary change, effected at a higher temperature, which hitherto could not be ascertained, for the want of an apparatus such as we have described. Upon Mr. Evans's principle of construction, any temperature may be uniformly applied to the whole mass of liquor; while by the old vessels this is impossible to be done, without injury to the products, for reasons before given.

It is likewise particularly deserving of notice, that there is a considerable economy in the application of heat by this method, for the fire acts uniformly upon the whole of the surface of the still, but in those of the ordinary construction, the fire does not act upon more than one-third, or one-fourth of the surface. [Register of the Arts.

Williams's Patent Apparatus for Distillation.

THE improvements projected under this patent are comprised under the following heads; viz. an enlarged capacity of the still-head, to cause a separation of the aqueous vapour by condensation, previous to its passing over the neck of the still, into the spirit condenser; in the employment of numerous small vertical tubes surrounded with cold water, to increase and accelerate the condensation; in the adaptation of a peculiarly constructed "cooling worm," by which, it is conceived, the quantity of spirit will be increased by preventing evaporation in its progress to, and when in the receiver;