duce being altogether 3,259 bushels, Winchester measure. They were reaped from the first to the middle of September, and the straw was used for supporting the working horses during the winter-months.

It is now proper I should explain my method of cleaning or ploughing the land, when the crop was on the ground, which was effected by a one-horse plough, without any hand-hoe being used. I first harrowed it completely before the beans appeared above ground, and water-furrowed and griped it. As soon as the beans would stand the plough a gentle furrow was given, and women were employed to turn any of the earth from the plants which might have been thrown upon them. Every succeeding furrow was taken deeper, and the last was used for laying the earth up close to the plants, which I consider as of great importance. They were ploughed four times; and I estimated the whole expense of cleaning them at 4s. per acre, and that of drilling and harrowing at 1s. 4d. In no other way can the ground be cleaned at a less expense.

The soil upon which they were sown was a loam of "different varieties. I have for many years practised this mode of husbandry for raising beans, which have uniformly been succeeded by wheat; and this year I have 110 acres, all managed in the way described. .

In the months of February and March 1800 I sowed with beans, according to the drill husbandry, 4 fields, consisting of 89 acres, 3 roods, and 6 poles, English statutė measure, which were succeeded by wheat, sown in the month of October following.

The soil upon which these crops were raised was chiefly of that variety generally characterised as heavy loam, though part of it approached to a soft loam; and nearly the whole was incumbent upon a bottom retentive.

of

of moisture. Owing to the uncommon wetness of the autumn and winter months, I was prevented from giving the ground more than one ploughing, except one field, consisting of 19 acres nearly, which was first crossploughed, and afterwards ploughed in length. The remainder was sown with beans, the intervals between the drills being 27 inches, in the months of February and March, 1800, after one ploughing; and the whole 89 acres were managed afterwards in the following

manner:

The ground was completely harrowed before the plants appeared above ground, and ploughed with one horse as early as the beans were able to stand the operation. This ploughing was repeated about two months afterwards, and so on as often as was necessary. The whole was ploughed four times during the summer months, and a part had five ploughings; and a picking of annual weeds by the hand was given to one of the fields. The total expense of drilling, horse-hocing, and hand-picking, amounted to about 5s. per acre, upon an average.

The kind of beans sown was the common horse-bean, mixed with a few peas, which were the best part of the crop. The season during the whole of the year 1800 was remarkably dry, which stunted the crop on the outset. The plants were therefore very short, and the produce when thrashed was only 18 Winchester bushels per acre; though I am convinced, if a greater portion of peas had been mixed with the beans, the return would have been much superior.

The ground, after carrying beans, was in excellent order; and, without any dung, yielded me a fine crop of wheat in 1801. The wheat was sown after one ploughing, in the month of October 1800.

Observations

Observations on the Decomposition of Acetite of Lead by Zinc in a metallic State.

IN

By L. ANTOINE PLANCHE, Apothecary of Paris,

From the ANNALES DE CHIMIE.

N consulting the different authors who have trcated of the history of metals, and their chemical action on the different productions of nature, we cannot but consider zinc as extremely valuable, as well on account of its utility in the arts, as for the essential services which it daily renders to chemistry.

Mr. Fourcroy, who in his Systéme des Connoissances Chimiques has collected the most numerous and the most authentic facts of the science, has described all its properties with that perspicuity and scientific accuracy pẹculiar to himself.

It is therefore not so much a new fact which I now submit to the Society, as the developement of that fact which, forming a part of a general theory, deserved a separate consideration, as one of the most important chemical phenomena. To proceed with the greater regularity, I think, it necessary to refer to the work of the. above-mentioned celebrated chemist; where, in the sixth section on metals, under the article zinc, it is said, "that zinc decomposes a great number of salts and metallic solutions by its powerful attraction for oxygen; that it precipitates the metals from them under a metallic form, or under that of oxyds, less oxydated than they were before."

This definition is doubtless just, and appears perfectly satisfactory. Yet it is capable of being developed to a far greater extent, and particularly in what relates to the

different.

different phenomena produced by zinc in contact with acetite of lead. To collect those phenomena is the principal object of these observations; to which I was led by the result of a most admirable experiment, attributed to Dr. Black, communicated to me in the year 1800, and to which I have made some additions.

This experiment of the Scotch chemist is as follows: into a quart decanter put 4 or 5 ounces of crystallized acetite of lead. Fill the decanter with common water, and shake the mixture. Then let it stand 15 or 20 minutes, or till the greatest part of the superabundant salt, after saturation of the liquor, be precipitated. In this solution, slightly agitated, suspend a piece of zinc of an indeterminate weight, by means of a silken or other thread fastened to the stopper of the decanter. Place the vessel in a proper place, and particularly where it will not be liable to be shaken. In 20 or 25 days the decomposition is completed: the zinc suspended in the midst of the liquor, then become transparent, is covered with a kind of metallic vegetation, of a very brilliant appearance, which frequently shoots to the bottom of the decanter, and is denominated by Dr. Black, the Tree of Saturn.

I have had occasion to repeat this experiment very often. It led me to various observations, in consequence of which I determined to make some slight alterations, which interfering in no respect with the chemical nature of the operation, eminently contribute to the beauty of the result. The alterations relate principally to the linen and silk threads, the decay of which, in consequence of their immersion in the liquor, occasions the fall of the piece of zinc, together with the new metal which covers it. In the place of those two kinds of thread I have therefore substituted brass wire, which appears to me to possess all the necessary properties, as well from its soliVOL. II.-SECOND SERIES.

Rr

dity

dity as its superior power of attraction over acetite of lead, owing to the zinc it contains. A second inconvenience occurs in strictly following the process described above. It frequently happens, that when the piece of zinc is too large, or the form of the vessel is not exactly suitable, the decomposition is effected with extreme rapidity, the particles of the new metal fly precipitately to the zinc, adhere to it in a confused manner, and in 2 or 3 days, sometimes in 24 hours, the crystallized portion is suddenly detached, and falls to the bottom of the vessel, to make room for a fresh crystallization. Thus the ope- .. ration is divided into several distinct parts, which is perfectly indifferent in a chemical view, but greatly diminishes the interesting effect of this beautiful experi

ment.

I prevented this inconvenience, by fixing perpendicularly to the bottom of the piece of zinc, the same kind of brass wires, turned in a spiral direction, and disposed in such a manner as to reach within about an inch of the bottom of the vessel.

By adopting this modification, every particle of zinc, composing part of the brass, the surface of which is in contact with the saturation, is covered with an infinite number of small and very brilliant metallic laminæ, disposed at first alternately and horizontally, and which afterwards cross each other in every direction *..

The quantity of acetite of lead must however be diminished, when the brass, although covered with the me

* The configuration of these lamina is infinitely varied, which appears to be occafioned, 1st. by the form, and different dimensions of the vessels in which the operation is performed; and, 2dly, perhaps likewise by quantities of zinc and acetite of lead employed in it. I have seen these laminæ sometimes circular, sometimes hexagonal, and sometimes even approaching the figure of fern or oak leaves.

tal,