DESCRIPTION OF THE PLATE THE Laboratory of the Surry Institution, at Black-friars Bridge, London, having been constructed agreeably to the design and under the immediate direction of Mr. Richard Knight of Foster-Lane; the author of this work, conceiving it to be one of the most complete experimental laboratories in the kingdom, obtained permission to make such drawings of the different apparatus as would enable any competenţ workman to construct a similar establishment. For this purpose the whole is drawn and engraved to a correct scale, which is placed beneath each compartment of the engraving. The upper part of the plate contains a section of the principal furnaces, in order to show their interior construction and the lower part represents a front view of the entire arrangement, on a smaller scale. AAA. Is a hood or covering extending over the whole, and communicating with two air-flues, B B, that pass through BB, the roof of the building, and are terminated by ventilators. These flues convey away any smoke or noxious vapour from the furnaces or other apparatus, without becoming offensive to the operator. C. A leaden sink, plentifully supplied with water. It has a drain pipe which carries off the waste water beneath the floor. D. A square sand-bath, heated by a fire-place, the door and register of which are seen, in the shade, on the right. EE. Two round apertures closed by stoppers, and com municating with a spare flue which is concealed in the wall of the building. These are intended to receive the iron pipes of such moveable furnaces as may be occasionally employed. F. Is a furnace containing an iron sand-pot calculated for distillation with a glass or earthen retort, as represented at F. in the section. This furnace is so constructed that the iron pan may be readily removed, and a copper still, an iron retort, or other apparatus, placed in its stead. GG. A muille-furnace for assaying metals by cupellation, for experiments on enamelling and staining glass, and for the roasting of metallic ores, &c. HH. À furnace for distillation by the naked fire. In the section H. is placed a retort, the neck of which passes through an opening left in the side of the furnace for that purpose, and which is luted up during an operation. This furnace is well contrived for the distillation of phosphorus, quicksilver, oxygen gas, &c. II. Iron doors opening on a level with the furnace grates, for the purpose of raking the fire, removing and replacing the bars, &c. KK. Doors of the ash pits. L. A smelting or wind furnace for the reduction of metallic ores, and other purposes requiring the highest degrees of heat. Section L. shows the interior of this furnace, with a crucible within it. M. is an aperture for clearing or withdrawing the bars of the grate. N. A reverberatory, or annealing, fumace. This forms a chamber through which the heated air and flame of the furace L. pass in their way to the chimney O. This addition is found to improve materially the draught of the furnace L, and is also particularly useful in heating crucibles to a proper temperature preparatory to their being used in that furnace. PP. Moveable covers suitable for either of the furnaces G, H, L, or N. These covers are made with fire-bricks ground neatly, and bound together by a strong rim or band of iron. There is a hole in the centre of each, secured by an carthen stopper, which may be opened occasionally to inspect the state of the fire or the progress of the operation. Q. An extended ash pit, covered by a moveable iron grate. This kind of ash pit very much economizes the room in a laboratory, as it admits a large current of atmospheric air, and allows the operator to stand closer to the furnace.— Throughout the whole of this apparatus, the chimneys are distinct, each furnace having its own; but being carried up within the wall of the building they cannot be described in this plan. R. fig. 3. represents Mr. Knight's table-furnace made of wrought iron, of dimensions according to the scale annexed, the inside of which is lined with a coating of fire clay. S. a door to allow the introduction of a crucible, &c. T. another door in the cover, through which the fuel (charcoal) is to be introduced. U. an opening which serves as a chimney when the top is taken off and a sand pot is to be used; or it will admit the neck of a retort for the purpose of distilling with the naked fire; this opening is also calculated for the introduction of a muffle. X. the door of the ash pit. WW. two apertures, opposite to each other, through which an iron, earthen, or any other tube may be passed, in order to demonstrate the decomposition of water, and for other operations which require such an arrangement. AN ESSAY ON THE UTILITY OF CHEMISTRY ΤΟ The Arts and Manufactures. Addressed to Parents in the higher and middle Ranks of Life. FROM the present state of chemical knowledge, and the rapid improvements in our arts and manufactures by the judicious application of its principles, it is become desirable that every youth should be acquainted with its rudiments, and that CHEMISTRY should be made a regular branch of education. I have therefore imagined that I should render an acceptable service to society by showing the advantages which arise from the acquisition of this kind of knowledge; for, as a large proportion of the community is not apprized of its real value, that general attention to it which it deserves, can never be expected until its utility be demonstrated. It would, however, be no difficult matter to show that the world might derive great advantages even from the dif fusion of a theoretical knowledge of philosophy and chemistry. An instance or two will place this assertion in a clear point of view. Two thousand years ago Archimedes was ridiculed for his attention to mathematics and the |