sustain the whole in aquilibrio when the phial is full of water to c d The finger screw at a is meant to adjust the sliding counter-weight e to make up for impurity or hardness in the water. The steel-yard from a to e should be carefully divided into, say eighths of an inch, that is, into 64 equal parts, this limb being 8 inches long from e. The Hordeometer now wants nothing but the figures to indicate the weights to be complete and fit at once for use. To obtain a standard for this purpose, reference must be made in the case of our first instrument to actual experiment; all subsequent ones may be taken from this as a model.

Select then a large parcel of good uniform barley, and have it as well mixed as possible; take a very accurate measure, and with the utmost care and by the most approved methods, measure out a bushel and have it exactly weighed and the weight noted. Repeat these measurings and weighings five or six times at least, and take the mean of the trials as the assumed weight of the barley, say 50 lb.; select a small sample of this, of as nearly an average quality as possible, and having put two measures of pure water into the phial so as to rise to m, pour in the barley till the water ascends towards the neck, and then drop it in grain by grain till it exactly coincides with the line c d. The phial having been carefully counterpoised before the barley was put in, it will require additional weights on the arm a e to restore the equilibrium.

The instrument just being described, is meant to weigh grain from 28 lb. to 60 lb. per bushel, and to indicate as low as half pounds.

Suppose the barley under consideration to have been ascertained to be exactly 50 lb per bushel.

Place a weight here so as phial and restore the equi

Begin at a and count off 20 graduations on the scale towards e, and mark the degree stopped at. exactly to balance the barley in the poise of the whole. It is manifest that when barley of unknown quality is on any future occasion by a similar process put into the phial, which may be counterpoised by the weight now ob. tained being put on this precise point of the arm of the steelyard, that that barley must just be 50 lb to the bushel, neither more nor less. We have thus got our first point, which may ac

cordingly be marked 50 lb. We may now engrave our figures on the steel-yard of which every second one will denote a whole pound, the intermediate graduations giving the half pounds; of course, by the use of lesser weights which may be multiples of the primary or large one, the indications may be brought down to ounces or half ounces, if the beam will turn with those.

If this process seem circuitous, it must be kept in mind that it is only resorted to in constructing the Hordeometer. The instrument once made, all that is requisite in using it, is first to put its various parts together, then to pour two fills of water from k l into fg, next to fill in the barley to be examined till the water rises to cd, and last to slide backwards and forwards the weight till the whole is balanced, when the figures on the limb of the steelyard will indicate at once the weight of the barley. The barley and water being now poured out and the phial dried, a second experiment may be entered on immediately. To save time, as the phials are cheap, it would be well to have two or three always ready, that the one might drip itself dry while another is being used.

Though barley is the grain which has all along been alone referred to, wheat, oats, beans, pease, or rye, may be equally examined by the Hordeometer, provided only their particles be heavy enough to sink in water. It may also be equally used for determining the gravity of spirits, wine, ale, or other solutions of whatever density or tenuity.

After the above details, it seems superfluous to say anything of the theory of the Hordeometer's operations. The whole consists in substituting a measure of water for an equivalent measure of barley. The object of doing so is, that we thereby are enabled to examine a fluid which is uniform and equable in its density, is very tractable and easily measured, instead of a congeries of irregular grains which individually vary in their consistence, and of which we can never depend on twice having the same number in a given measure. As we cannot take fractions, 400 or 500 grains of barley should always be employed at least, if we wish to come within half or quarter pounds in the weight. This suits very well with another condition of the instrument, the amount of water displaced by a single grain being as small a

quantity as can be distinctly observed in a phial of convenient width of neck.

We here employ the principle of a constant and uniform measure and a variable weight. Should the application of the converse of this be found more convenient in practice, it is equally accurate in theory. In this case we might have a balance with a constant weight attached, so that it would always be poised by one ounce of barley. This quantity we should pour into the long stemmed vessel r, fig. 1, so constructed that its neck being about inch wide and 8 inches long, should hold as much water as its bulb; a funnel-shaped mouth being formed at r for the conveniency of pouring in the grain. In this case the pounds weight would be indicated by the rise of the water in the graduated stem.

We restrict in fact to no particular form, but contend that nothing can be productive of better results than the principles of measuring here recommended.

Should scales be used instead of a steel-yard, which may indeed be more accurate for the first experiments;—having found the weight corresponding to barley of 50 lb., all that is requisite is to divide this into 50th parts for single pounds, and 800th parts for ounces, a process very easily effected by the use of common troy weights and the most ordinary druggist's balance. The precautions to be used to obtain a perfect average in a fundamental or model Hordeometer will occur to any instrument maker.

PATENT RECTIFYING STILL.

THE construction of this distilling and rectifying apparatus, is exhibited in section in the accompanying plate, and consists of an ordinary still, between the head of which and the worm-tub is arranged a series of two, three, or more vessels, A A' A", which, from their office, may be termed rectifying vessels, through which the mixed aqueous and alcoholic vapours successively pass in their course from the still to the worm. The vapours issue from the still through the tube a, which opens at the bottom of the first rectifying vessel A, where they are condensed; they

again rise, and, coming in contact with the metal tops, or domes B, a considerable portion of aqueous vapour is condensed; while the remainder, with the alcoholic vapour, pass off from the centre of the dome through the tube a', which discharges them in the bottom of the second rectifying vessel A', at the top of which an additional portion of the aqueous vapour is condensed, and the remainder with the alcoholic vapour pass off in a similar manner by the tube a", which discharges them in the bottom of the third rectifying vessel A", at the top of which a similar process of condensation of the aqueous vapour takes place, and the alcoholic vapour, with the very small remnant of aqueous vapour, pass from the top of the dome to the worm in the worm-tank, and are condensed in the usual manner. By this process of a separate condensation of the aqueous and alcoholic vapours, a very strong and pure spirit is obtained at one operation. The sides and bottoms of the rectifying vessels A A' A", are constructed of wood, which is an imperfect conductor of heat, and the top of each vessel is closed by a dome-shaped covering of sheet copper, B B B, which is a rapid conductor of heat; and it is this combination of slow and quick conductors of heat in the construction of his rectifying vessels, for which Mr Shand claimed his patent. Owing to the slow permeability of wood by heat, the temperature of the condensed water in the bottom of the rectifying vessels is preserved at such a point, that the greater part of the spirit passes through without losing its gaseous form; while any spirit which may have been condensed is reconverted into vapour. The wooden sides of the vessels extend somewhat higher than the copper domes, as is shewn at CCC, for the purpose of holding water or wash, by which the metallic heads, BB B, are preserved at a proper temperature for condensing the aqueous vapour; bbb" are three air-cocks for the rectifiers. A gutter from the centre of the bottom of each rectifier conveys the liquid deposited during distillation, through the cocks dd d into the boiler; e e e are three cocks and pipes intended to regulate the proportion of aqueous matter in the bottom of the rectifiers, and allow any excess deposite to pass back into the boiler; fff are three distinct cocks for reducing or removing the water from the domes B B B; ggg are three spouts for taking off from the upper part of the domes the surface water;

h is a vessel to contain water for the rectifiers, with pipes and cocks connected therewith, and a gauging rod therein.

The most suitable dimensions for the rectifying vessels to that of the still, are found to be, for a 600 gallon still, the vessels should have capacity, the first A, of 200 gallons; the second A', of 130; and the third A", of 100 gallons.

The common still is perhaps the most ancient piece of mechanism in use in this country; and in almost every instance is yet preferred to any other. This patent apparatus, however, is simple and unexpensive, is more easily managed than the common still, and economises fuel and time. It yields a strong and better spirit, more in quantity, and with less feints than any other process. The products are free from acid, consequently less prejudicial to the stomach.

It must be evident to the most superficial observer, that when heat is by any means communicated to the lower part of any metallic vessel, and cold to the upper part of the same vessel, a very great proportion of the heat must be drawn up through the metal, and dissipated; but if the bottomand sides of the vessel be of wood, or of any nonconducting substance, little heat can pass through the wood, and nearly the whole of it must ascend through the interior; consequently it will act more powerfully on whatever may be contained in the vessel, and in so acting must be economised. For these reasons cold may be applied in a greater degree, and with more effect, at the proper point where condensation is necessary. The surface on which the cold acts being very limited, the temperature in the rectifier can be raised quickly, and more caloric allowed to pass to the succeeding vessel, and retain sufficient power to separate the alcohol when the proportion of the latter is very little to the water. It is also apparent that most beneficial effects are produced in the lower part of the rectifiers, the vapours being there condensed, and again raised from the surface of the boiling liquid as in a common still, but with a modified temperature. The alcoholic particles being apart from each other from the time they leave the boiler, are separately washed, and leave a portion of the aqueous matter by which they are surrounded in each bath. It is difficult to determine the various causes which lead to the preservation of so large a proportion of alcohol, but