two sacks, which were equally filled.
All the coals brought to the London market are publicly sold, only by the whole, half, or quarter ship. Those who have neither craft nor wharfs to unload, at the rate of 40 chaldrons per day, purchase from some of the greatest coal-merchants: this is called loading on account; and the former pay 1s. per chaldron for commission.
Pool-measure is one-fourth of a chaldron extra, on any five chaldrons; and a room of coals of 514 chaldrons, contains about 68 sacks of three bushels each, or somewhat less; but this quantity may be divided into from 70 to 90 sacks, if they are filled up, and not measured by the bushel, under the inspection of a sworn meter. The pool measure, therefore, being larger than the bushel measure, the profit of a coal-merchant may be estimated, upon an average, at five sacks upon five chaldrons, that is, at about 8 per cent.
Coals constitute one of the chief articles of domestic convenience, especially during the severity of winter. Hence, in that season, they frequently become extremely scarce, and are sold at an extravagant price. To remedy this evil, in some measure, a preparation of clay and coal-dust has been successfully employed; of which we shall communicate the following particulars:
Coal-Balls: Take two-thirds of soft, mellow clay (for instance, a ton), which is free from stones, and work into it three or four bushels of small sea-coal previously sifted; form this composition into balls, or cakes, about three or four inches in diameter, and let them be thoroughly dried. When the fire burns clear, place four or five of these balls in the front of the grate, where they will soon become red, and yield a clear and strong heat, till they are totally consumed. The expence of a ton of this composition is but trifling, when compared with that of a chaldron of coals, as it may be prepared at one-fourth of the cost, and will be of greater service than a chaldron and a half of the latter.
A similar kind of fuel is prepared in the Bishopric of Liege, and is a source of considerable emolument to the inhabitants, who sell great quantities of it annually. A correspondent in the second volume of the "Museum Rusticum, &c." mentions this preparation, and adds, that he has seen several fires of it burning in the house at that time occupied by the Royal Society, in Crane-court, Fleet-street. We therefore seriously recommend this article to the attention of those, who, together with the ability, possess the means of alleviating the wants of others.
A patent was granted, in the year 1800, to Mr. Frederic, of Wellbeck-street, for his invention of a fuel, which burns longer than the common coal. As the patentee has published part of the process, in a separate treatise, we shall extract from it the following particulars: The principal ingredient is clay, or where that cannot be procured, cow-dung, road or street mud, saw-dust, turf, horse-dung, straw, and especially tanners' waste; to which may be added, broken glass pulverized, or pitch, tar, oil-cakes, or any other combustible matter, that is not too expensive. These are to be mixed with coal-dust, in circular pits, five or six feet in diameter, and paved at the
