Daily National Intelligencer

AGRICULTURAL.—USE OF GYPSUM.

WASHINGTON, JAN. 29, 1820.

Gentlemen: By giving place in your very useful paper to the inclosed extract from the Boston Palladium, you will subserve essentially the interests of agriculture. And I hope that other Editors, not exclusively occupied by politics or commerce, will do the same. I am informed that the establishment of which it treats is now in full operation, under the direction of Mr. Binon at Boston.

Your constant reader,

A FARMER.

Under the article of Gypsum, in Rees' Encyclopedia, will be found the following paragraph: —

"It is supposed that two bushels of Plaister will suffice for an acre in drills. French and Nova Scotia Gypsum were used, being first ground fine. In this country, six to eight bushels have been employed per acre. The success has, however, been very far from what might have been expected, from accounts that have at different times been published concerning it."

The quantity of Plaister which was employed in this account, leads to the suspicion that there must be some fault in the mode of preparing it, since more than one half of its expected effect seems to have been lost—and that suspicion is fully confirmed, by the experience of some very intelligent agriculturists in this neighborhood.

We had formerly recommended the use of this manure, and we have been at some pains in tracing its progress and effect, with a view to ascertain the grounds of the common objection, of the vicinity of the sea, which is said to diminish greatly the beneficial effects which it has on land farther removed from the sea air. We have also made a more particular inquiry into the mode of preparing and using it in the Southern Provinces of France—situated immediately on the sea-coast.

Conversing on this subject with an inhabitant of the south of France, who was about to establish a manufacture of plaister mouldings and ornaments, we were so fortunate as to find in this individual a confirmation of what we had learned from other sources—and one who was able and disposed to instruct us in the practice of that of which we had before a faint notion of the theory.

This person, at our request, has determined to extend his works, so as to be able to furnish plaister as is prepared from manure in France.

Plaister, employed as it now is, can but partially realize the expectations of the Agriculturist— it would be of little or no benefit, if it had not received a degree of coction from the heat produced by the act of grinding, and the mechanical effect which the grosser particles, like sand, have in rendering a heavy argillaceous soil more friable.

It is then only the impalpable parts of the Plaister, as it is now used, and which are partially calcined, that afford some feeble nourishment to vegetation—and the coarser particles must wait till the action of the air shall have reduced them to a state which is susceptible of vegetable affinities—and if they should be carried by deep ploughings and their own gravity beyond the reach of atmospheric influence, they are then lost.

Mineralogical details of the constituents of Gypsum, would be here superfluous—it will be sufficient to show, as succinctly as possible, that Plaister, properly prepared, will offer the same results here as it does in other countries. It would seem that the most important branch of preparation was the burning, and we are informed that this is the great secret of the art. The kiln must be carefully constructed so as to admit no external air; the calcination must be carried to that point which will dispose the grains of Plaister to fall into an impalpable dust, when exposed to the humidity of the air; and stopping scrupulously at that critical point, lest too great a degree of heat should cause to evaporate the sulphuric acid, of which it is said to contain 72 parts in a hundred. This proper degree of calcination disposes the plaister to warm the earth by a chemical decomposition of its vapours, and at the same time attracts the damps of the air, as all bodies do when deprived of their hydrogen.

Our informant tells us that Plaister prepared, as he proposes to do it, for manure, loses but fifteen per cent. of its original weight; and this appears to agree with the analysis, which gives sulphuric acid, lime, and water—the water is probably the only constituent which is evaporated when the operation is properly performed.

In some countries Lime is used, and is found to be beneficial on certain soils: we should, however, give the preference to Plaister on account of its sulphuric acid, which has, of itself a very strong affinity for hydrogen, but is a powerful menstruum on all animal and vegetable matter.

The objection to the use of Plaister on the sea coast must be founded in error, for we remember to have seen the most abundant crops of wheat in situations absolutely bathed by the salt water; but if the only advantage to be gained by this new mode of using Plaister should be celerity in its effect, and no absolute and ultimate advantage over the old mode were to be expected, we conceive that this circumstance will prove a powerful recommendation in a country whose inhabitants are ever in a hurry for immediate enjoyment; but we remain of opinion that some sound arguments may be adduced from chemistry in favor of it; and we hope that the trial will be made, and its projector be properly encouraged.