NOVEL INVENTION.

JOYCE'S HEATING APPARATUS.

WITH Confidence it may be asserted, that no invention, connected with the arts and sciences, ever created so extensive and rapid a sensation within a few days as the new heating apparatus invented by Mr. Joyce has done. We understand that orders for more than three thousand stoves have been received at the Jerusalem Coffeehouse in London, and that numerous applications for permission to sell by way of agency have been forwarded from all parts of the country.

As we believe no authorised notice of this invention has yet appeared in print, and that those which are before the public tend more to mislead than inform, we have thought it our duty to state so much of the matter as, under circumstances, we feel ourselves at liberty to explain, the specification of the invention not having yet been inrolled.

There are two features in this invention, the one is a stove of a peculiar construction; the other, a chemical preparation of materials for fuel.

As to the stoves, they are of a cylindrical form, of thin copper or iron, ornamented externally in various parts, and having a neat dome at top, and scroll feet at bottom, with internal arrangements for the passage of atmospheric air which escapes from the fire through a regulator in the dome; this regulator also acting as a damper, which determines the amount of draft, and consequently controls the combustion of the fuel within, thereby regulating the amount of heat evolved.

The most important feature of this invention is the fuel, a matter which, having been first chemically prepared, does not, during its combustion in these stoves, give out either smoke, smell, or any deleterious vapour, a fact which, however singular, has been witnessed by thousands.

It does not appear that this discovery is to be attributed to a very profound chemical knowledge, for the walks of chemical science

have been widely trodden by talented men of the first order who have passed by the principles which have been now called into action without developing them; neither has it arisen from accidental circumstances, for the Patentee has been many years engaged in the pursuit of the object he has now obtained; has approached it very gradually, and, by dint of unremitted perseverance and a multitude of other experiments, has, at last, reached the point he sought, beyond which he does not anticipate any further beneficial discoveries.

The principles on which this invention is founded, in our opinion, are fundamentally correct; and though they appear to have been overlooked by those who have before trodden in the same paths of science, yet the fact is unquestionable, that combustion is effected in these stoves without deleterious exhalation.

The materials are cheap, and readily to be obtained in all countries. It is said that a small cylindrical stove of eighteen inches high, and seven inches diameter, will give out heat enough to raise the atmosphere of a room of twenty-five feet square, from thirty to forty degrees above its natural temperature, and keep it at that heat for thirty hours without attention at the small cost of four pence.

SCIENTIFIC NOTICES.

REPORT OF TRANSACTIONS OF THE INSTITUTION OF CIVIL ENGINEERS.

(Continued from p. 182.)

March 7, 1837.

The PRESIDENT in the Chair.

"Account of a Machine for cleaning and deepening small rivers,

in use on the Little Stour River, Kent; by W. B. Hays, A. Inst. C. E."

The application of this machine to scour out small rivers consists in taking advantage of an artificial head of water to force on, with

the assistance of a small current, a boat armed with scrapers. At the stern of the boat is lowered a vertical frame, with scrapers at the bottom, and to the sides of the boat, near the stern, are atTM tached wings, which being opened out make a dam. Thus a small head of water may be obtained, and the boat is forced on; the mud and weeds being raked up are carried down to the mouth of the river.

Drawing and Description of a Bridge erected over the River Calder, at Mirfield, Yorkshire, by William Bull, A. Inst. C. E." This arch, composed of two ribs of fir timber, is 147 feet 6 inches span, 11 feet versed sine, 5 feet wide at the centre, and 8 feet at the abutments.

On Experiments on the strength of Materials. By Thomas Webster, M.A.; Sec. Inst. C.E."

The object of this paper was to point out the importance, in making experiments on the strength of materials, of beginning with weights sufficiently small. In the series of experiments on the strength of various timbers by Lieut. Denison, laid before the last meeting of the Institution, the first weights are in some cases too large; for, from the commencement, the deflection increases more rapidly than the imposed weight.

The points to be ascertained in all experiments of this kind are, first, the weight which a beam can bear, the elasticity being unimpaired, or the elastic weight; and, secondly, the breaking weight. So long as the deflection increases in exact proportion with the increase of the weight, we may consider that the elasticity is unimpaired; but if the deflection increases in a higher ratio, that is, if the deflection for one cwt. be one inch, and for two cwt. more than two inches, we may suspect that some violence is done to the elastic force of the material. Thus a guide is furnished us in our observations; the weight before this ratio is observed to change must be considered as the elastic weight. When a beam is to be

broken the effect of time should be noticed, and the increased deflection after a given number of seconds recorded.

The experiments of Lieut. Denison bear out these remarks; for it will be seen that the point at which he has noted the first permanent set is in very many cases immediately after the change which is here laid down as the condition for determining the elastic weight.

With respect to the strength of materials, Mr. Cotton stated that it had often occurred to him, whether, if a beam be loaded by ever so small a quantity beyond the elastic weight, this beam would not in time be broken. This consideration might, he thought, explain some apparent difficulties, as when a beam breaks suddenly without any increase in the weight, but having been loaded to the same amount for many years.

The effect

inch, was

Mr. Hawkins mentioned a case, in which a beam that deflected too much had been sawn down its middle and bolted up, so that its depth was increased in the centre from 10 to 11 inches. of this was that the deflection, instead of being about 1 on th of an inch. Was this great increase of strength to be attributed to the increase of depth simply, or to the lower half having become a truss and the upper a strutt?

March 14, 1837.

The PRESIDENT in the Chair.

The decay of timber in contact with stone was discussed, and several instances were mentioned in which the only decayed part of timber was that in contact with stone. This decay is entirely obviated by inserting the wood in an iron shoe, or by placing a thin piece of iron betwixt the wood and the stone. Several cases were mentioned in which the iron shoe had been found a complete protection against dry rot and decay; a hard crust is formed on the timber in contact with iron, which seems effectually to preserve it. It was suggested that the system of grouting must contribute to the early decay of timber; bond timber had consequently been replaced by bond iron. Bond timber is used very generally at Man

chester, and answers exceedingly well, but the high temperature of the buildings may be a preventive against the decay of the timber, as the walls are very soon dried.

The subject of the strength of materials was resumed from the last meeting, and especial reference was made to the experiments by Mr. Hodgkinson on the strength of iron girders, published in the Transactions of the Manchester Society. In this paper Mr. H. supposes the forces of extension and compression to have a ratio 1: n; and not that, within the elastic limit at least, this ratio is a ratio of equality. Also, these experiments are directed especially to determining the form of beam which will be strongest up to the instant of fracture; or, in other words, the beam which will have the greatest breaking weight without any reference to the elastic weight,

These principles are contrary to those laid down by Tredgold, and to the opinions of many persons of great experience. Mr. Donkin and Mr. Francis Bramah maintained that within the elastic limit the forces of extension and compression are equal; that consequently within this limit the deflection will be the same, whether the beam is laid with a particular edge highest or lowest; that a beam, for instance, whose section is a triangle, will exhibit the same deflection within the elastic limit, whether the vertex or base of the triangle be laid uppermost; beyond this limit, however, the case is different.

The strength of a beam, according to Mr. Hodgkinson's experiments, depends on the bottom flanche; by increasing this he had made beams for which the breaking were 4000 the square inch of surface of section, whereas Tredgold's strongest forms were about 2500 the square inch.

March 21, 1837.

The PRESIDENT in the Chair.

"On the strength of Iron Girders, by W. B. Bray, A. Inst. C.E." In this paper the author states the rules which had been given by Galileo, Tredgold, and Hodgkinson, for calculating the strength