bottom with bricks. In one of these pits, some clay should be previously softened with water, and well worked with an iron rake; after which operation, any other of the ingredients may be added in the following manner: Two men provided with a pail should first fill one of the pits a foot deep with clay, and throw in the small coal, together with the other ingredients, according to the quantity and proportion required. The whole should then be stirred repeatedly with a large rake, and the pit progressively be filled up, till the clay becomes so thoroughly incorporated with the other substances, and acquires such a degree of consistence, that it can no longer be stirred. More clay should be added; and the same operation repeated till the pit is full; when the mixture should remain in it, till the water is in a great measure evaporated, and the composition becomes fit for use; during which time another pit may be filled in a similar manner.
When the mixture has acquired a sufficient degree of consistence, and is ready to be formed into cakes, a mould made of deal, about four cubic inches square, should be prepared, and previously wetted, to prevent the mass from adhering to it; but, before this composition be put into the mould, Mr. Frederic recommends saw-dust to be spread over it, by means of which the cakes will dry more quickly, and burn much better. The last operation is that of drying, which should be effected in a shed, about seven feet high, and as long as may be necessary. The cakes may also be dried on the ground, in the open air, but as they are liable to be wetted by rain, the labour already bestowed upon them would be useless. A shed, therefore, if it can be procured, is most eligible, and should be divided into upright rows six or seven feet high, about three inches thick, and three feet distant; being intersected every six inches by a cross bar twelve inches in length, for receiving, on both sides, laths of about three quarters of an inch thick; and which should be about two inches and a half apart. On these laths, the cakes are to be laid for drying, which, during the summer, will take place in less than a week.
This invention, we conceive, is of considerable utility, and reflects great credit on the patentee, who has voluntarily consented to relinquish his privilege, and offered to explain his process to any public establishment, or charity, that may be inclined to prepare these cakes, upon a large scale, so as to sell them at a reduced price, and thus furnish the poor with that most necessary article of domestic comfort, fuel.
Use of Coals as manure.—The first experiments for ascertaining the effect of pounded coals, or their ashes, on the fertility of meadows and corn-fields, we believe, were made in Germany, by Counsellor Stumpf, about the year 1791. On account of the vitriolic acid contained in coals, they are, for this purpose, superior to gypsum, especially on cold, calcareous soils. According to his directions, the coal-dust, or powder, ought to be scattered on the fields, late in autumn, about the thickness of the back of an ordinary knife, so that he employed about four cwt. of coal to manure a German acre of 180 square roods, Rhenish measure. But, as there is a great difference between those coals, the residue of
