"SIR,

SIMPLE LAMP FOR BURNING FAT.

"To the Editor.

In a former number (57) of the Register of Arts, I notice the description of a recently patented invention, by the Hon. E. Cochrane, for a lamp to dissolve and burn fat, and other concrete oily substances. It is now more than twenty years ago that I made a lamp of this kind, by which I burned tallow, dripping, goose-grease, and other solid oily matters, very effectually and conveniently; of the construction of which, I here annex a perspective sketch, should you deem it worthy of a place in your popular and interesting work. It is a simple cottage candlestick lamp, but, lamps on the same principle are capable of being rendered elegant: the addition of a glass chimney would be a great improvement.

"a is the fat rendered fluid, lying in the body of the lamp; (the cover of the lamp being removed to sliew the interior); c is a small tube to convey air into the middle of the flame (to perfect the combustion, on the principle of the argand burner); this tube opens at the lower end into the large tube b, as shewn by dots; a small perforation is also made at d, to allow the air to flow freely into the tube c, when the lamp is fixed in the socket of a candlestick. On each side of the air tube a short piece of copper pipe is fixed by hard solder, for holding the cotton wicks; (these tubes (which ought to be longer) get intensely hot, and, by the conducting power of the metal, the heat is transmitted to the fat, which, melting in consequence, flows up the wick like fine oil, but infinitely preferable, on account of its diffusing no unpleasant smell during the combustion.

"Pentonville. February 14, 1826.

"Your constant Reader,

"D. H."

The sea

THE MENAI BRIDGE.-The chain bridge just finished over the Menai ferry, and opened within the last few days, it perhaps (with the single exception of the Simplon Road) the most stupendous monument of human art in the whole world; and places Mr. Telford's name on the very proudest elevation of professional fame. rushes in a dark and turbulent confusion of currents between the precipitous shores of Anglesea and the main land; many small rocks partly hidden except at low water, augment the perplexity and danger of the passage; the winds blow furiously down the ravine, and produce even when the weather is moderate elsewhere, a perfect tempest of spray. Altogether, except in the first season of the year, the old

Menai ferry was a sufficient trial for not the weakest of nerves. The narrowest part of the straight is 500 feet in width, and here it is now crossed by a convenient bridge 30 feet in breadth, suspended 100 feet above the surface of the water, from enormous stone buttresses 152 feet in height.-Literary Gazette.

LETTERS OF ENQUIRY.

Essential Oil of Walnuts.-M. S. is desirous to be informed of the process to be adopted for obtaining the essential oil of walnuts. Varnish.-AN ARTIST wishes to learn the process of making a colourless spirit varnish.

LIST OF NEW PATENTS.

INLAND NAVIGATION.-To H. A. Keymans, of Warnford Court, Throgmorton Street, for improvements in the construction and use of apparatus and works for inland navigation. Jan. 16. Six months.

SPINNING. To J. F. Smith, of Chesterfield, Derbyshire, for improvements in the process of drawing, roving, spinning, &c. Jan. 19. Six months.

CULINARY UTENSILS.-To W. Whitfield, of Birmingham, for improvements in the making of the handles for saucepans, kettles, &c. Jan. 19. Six months.

HINGES.-To Benjamin Cook, of Birmingham, for improvements in the construction of hinges of various descriptions. Jan. 19. Six months.

APPLICATION OF STEAM.-To A. R. Lorent, late of Gottenburg, but now of Queen Street, Cheapside, for a new method of applying steam to pans, boilers, coppers, stills, pipes, machinery, &c. and regulating the same. Jan. 19. Six months.

MASTS.-To Sir Robert Seppings, of Somerset House, for an improved construction of masts and bowsprits. Jan 19. Two months.

AXLE-TREES.-To Robert Stephenson, of Bridge Town, Old Stratford, Warwickshire, for improved axle-trees to remedy the extra friction on curves to waggons, carts, &c. Jan. 23. Six months.

TO OUR CORRESPONDENTS.

W. B. Junr's. Paper we have never seen; search will be made for it at the Publisher's.

A. Z. will find, in our 55th number, that a correspondent has anticipated him by a similar communication: we much fear that his new instruments would be too troublesome to become of any practical advantage.

We know not what to say, in this place, to our old friend ADOLESCEN'S. He presupposes that a vacuum can be effected (as was too generally supposed) by the means alluded to, but it unfortunately turns out to be otherwise, or to only a very partial extent. There has been no difficulty experienced in simplifying the mechanical arrangements, and these have availed but little, as the defect is owing to a chemical cause; and until this defect is remedied, the publication of any improvements in the mechanism would appear ridiculous.

i

Published by JOSEPH CAPES, Bookseller, 111, Fleet Street, where all Communications for the Editor are requested to be addressed.

Sold by GEORGE HEBERT, A8, Cheapside ;-SHER WOOD, GILBERT, & PIPER, Paternoster Row; SIMPKIN & MARSHALL, Stationers' Hall Court; COWIE & STRANGE, 60, Paternoster Row; and may be had of all Booksellers in Town and Country.

PRINTED BY COE AND MOORE, 27, old change, st. Paul's.

OF

THE ARTS

AND SCIENCES.

SATURDAY, MARCH 11, 1826. [Price 4d.

MR. BRUNEL'S NEW PATENT CARBONIC ACID GAS ENGINE.

Ir affords us the highest gratification to be enabled to fulfil our promise of giving in the present number, a full and accurate description of this truly important invention, which, from its superior and almost illimitable powers, there is every probability that it will in the course of time, supersede, to a great extent, the use of steam in motive engines.

Previous to the year 1823, carbonic acid had never been exhibited but in the gaseous or aëriform state, and it was a commonly received opinion, that no degree of pressure, or of cold, would cause it to assume a more concentrated form; in the early part of that year, however, Mr. Faraday of the Royal Society, under the direction of its illustrious president, Sir H. Davy, succeeded in reducing it (as well as several other gases) into a liquid state, by the mechanical pressure of a condensing pump.

This liquid, at the temperature of freezing water, in its endeavour to assume the aëriform state, exerts an expansive force equal to 30 atmospheres; at ordinary temperatures, a force of from 40 to 50 atmospheres; and on a heat of only 120° Fah. being applied, the force is increased to 90 atmospheres; the pressure increasing in a similar ratio for higher degrees of heat; in other words, at the rate of about 11 or 12 pounds increased pressure upon the inch, for every single additional degree of heat.

To construct an apparatus by which a power so immense, and apparently so economical, might be rendered available, like the steam engine, as a first mover to all kinds of machinery, we may easily conceive has occupied the attention and study of many of the most scientific and clever men, not only of this, but of every country in the civilized world; since it cannot be doubted that the paper of Sir H. Davy, "on the application of liquids formed by the condensation of gases as mechanical agents," has been published every where, and translated into the languages of all countries where mechanics is studied as a science. Nearly three years have intervened since the publication of the important facts detailed in the paper alluded to, during which period, not only individual talent, but the abilities of one of our first chemists have been united with those of one of our most eminent engineers for the accomplishment of this great desideratum. In this honourable spirit of rivalry, however, the splendid talents of MARC IZAMBARD BRUNEL, Esq. have shone triumphant; notwithstanding the attention requisite to his other great works now in progress, he has found the time, and the means, by a few simple and admirable com

binations, to outstrip in the career all his contemporaries; and to present to the world the first carbonic acid or expansive gas engine.

It is proper that we should here remark that the patent right for Mr. Brunel's apparatus is not limited to the employment of carbonic acid, but that it extends to all liquids which are the result of the condensation of the gases. The preference being however given to the former, we may perhaps infer that the engine we have to describe is better adapted to the peculiar properties of carbonic acid gas than to those of the others. Carbonic acid gas may be obtained by decom posing any of the carbonates by the action of the common acids. The mode of obtaining the liquid from the gas is by forming the gas under a gasometer, and condensing it afterwards in another vessel by means of a condensing pump, and continuing the operation until it passes to the liquid state.

The apparatus, as shewn at fig. 2, consists of five distinct cylindrical vessels; the two exterior vessels a and b contain the carbonic acid reduced to the liquid form, and are called the receivers from these it passes into the two adjoining vessels c and d, termed expansion vessels; these last, having tubes of communicaton with the working cylinder e, the piston therein (shewn by dots) is operated upon by the alternate expansion and condensation of the gas, giving motion to the rod f, and consequently to whatever machinery may be attached thereto.

As the working cylinder e is of the usual construction, no further description of that part of the apparatus is necessary; and as the two vessels on one side of the cylinder are precisely similar to those on the other, a description of the receiver a and the expansion vessel c, will apply to their counterparts b and d; the two former (a and c) are therefore given in a separate fig. (1) on a larger scale, in section, that their construction may be seen and their operation better understood. The same letters of reference designate the like parts in both figures.

The communication of the condensing pump (before-mentioned) with the receiver a is through the orifice g which can be stopped at pleasure by the plug or stop cock h. When the receiver has been charged with the liquid and closed, a pipe i is applied to and connected to the expansion vessel cat k. lisa lining of wood.(mahogany) or other non-conductor of heat, to prevent the absorption which would otherwise be occasioned, by the thick substance of the metal. The expansion vessel is connected through a pipe m to the working cylinder e; these vessels contain oil, or any other suitable fluid, shewn at n, as a medium between the gas and the piston.

The receiver is a strong gun-metal vessel, of considerable thickness, in the interior of which are placed several thin copper tubes as represented at o oo; the joints of these tubes through the top and bottom of the receiver are made perfectly tight by packing. The use of these tubes is to apply alternately heat and cold to the liquid contained in the receiver, without altering very sensibly the temperature of the cylinder. The operation of heating and cooling through the thin tubes ooo, may be effected with warm water steam, or