MONNOM'S BORING APPARATUS as we found itqby our observations in prolonging the meridian, we shall find, that at the height of St, Pilon above the sea, which is 481 fathoms the real depression of the horizons should be 58 571, which is greater by 25than the mean apparent dé pression, 56′52′′. This excess must be owing to the refraction, which raises the apparent visual ray above the true one, by about the twenty-eighth part of an angle of the mean apparent depression Juoda zainude stad en NO. 137. VIOLIN VARNISH. // F. Laval remarks that the refracting of a Violin, I shall feel SIR,-Having completed the maktion is greatest when there is a fog to any of your intelligent Corresponobliged in the air, occasioned by a north- dents, who would inform me how I west wind and that it is greater or could make or procure a good transless as the wind is more or less fresh. parent oil varnish, that would not he detrimental to the sound, or destroy the beauty of the wood, as I find the common varnishes have both these qualities. 1/15-I'am, Sir, Your obedient servant, 70 30%ASASTIK TABANII RETAW WOJ ⱭZA HOIH 12 TO330 MONNOM'S BORING APPARATUS. Jasbro429170) 1361-312 Singershave read with much in terest, in your Number 86,vthes des scription of a Boring Apparatus by M. Monnomy but as many inventions, however apparently good in W. FELL. theory,//may occasion disappoint- ANSWER TO INQUIRY. ment when practically applied, I request that he actual trial of it, for what purposes, and with what success. It is to be hoped that hewill also be able to furnish an estimate of the probable cost of the machine complete, and to point out where it may be seen at work. › Jd of 191910 Pam, Sir, ma state if he has made so good as to 9 to EGYPTIAN ORE, 9 t NO # Trailosza 1907 at 134.—VARNISHING STUCCO. bold 19m 9 IMAGES.[4 £1sq.9¶ SIR,In reply to the inquiries of "Aurum," I am glad to be able to inform him, that figures made of plaster of Paris may be easily and beautifully varnished by means of the following composition. The pro portions which are best, I have not exactly ascertained. bam indebted to some one of the periodical publis cations for the receipt to which of them I cannot now recollect. ul. Jad The materials are white wur, soup, and water. It is obvious that the wax is dissolved by the soap in the water at a boiling heat. This varnish does not sink in, as that complained of by your Querist: it readily dries; and its effect may be heightened by lightly using a silk pocket-handkerchief. I have employed this varnish with remarkable success to the casts of cameos, which, when thoroughly dry, may be finished by means of a clean camel's hair pencil. On mentioning my method to an Italian who furnishes me with,nu 304 NEW PATENTS-CORRESPONDENCE. merous casts, he suggested the sub- I am, Sir, Manchester. NEW PATENTS. J. Fox, Plymouth, Devonshire, rectifying distiller; for an improved safe to be used in the distillation of ardent spirits.-May 14. C. Mackintosh, Crossbasket, Scot-, land; for a new process for making steel.-May 14. J. Badams, Ashted, near Birmingham, chemist; for a new method of extracting certain metals from their ores, and purifying certain metals.-May 16. I. Reviere, Oxford-street, gunmaker; for an improved construction, arrange ment, and simplification of the machi nery by which guns, pistols, and other fire-arins, are discharged.-May 20. W. H. James, Coburg-place, Winsongreen, near Birmingham, engineer; for certain improvements in apparatus for diving under water, and which apparatus is also applicable to other purposes.May 31. J. F. Ledsam, merchant, and B. Cook, brass-founder, both of Birmingham; for improvements in the production and purification of coal gas.-May 31. J. Crowder, New Radford, Nottingham, lace net manufacturer; for improvements on the Puslew bobbin nét machine.-May 31. J. Apsdin, Leeds, bricklayer; for a method of making lime.-June 7. C. Powell, Rockfield, Monmouthshire; for an improved blowing machine. June 6. A. Bernon, Leicester-square, merchant; for improvements in fulling mills, or machinery for fulling and washing woollen cloths, or such other fabrics as may require the process of fulling June 7. TO CORRESPONDENTS. The trickery to which "Glasguensis" alludes had not escaped our notice, but we imagined it scarcely deserved exposure. Shortly after the commencement of the Glasgow Mechanics' Magazine, we hailed its appearance most cordially, as a worthy ally in that new field of usefulness, in which we were the first labourers, and we did say that it was a clever work," and, "though sold at the same price, is printed on a finer paper, and in a more showy manner, than ours;" but we added, at the same time, that" it did not, on an average, contain one-half the quantity of matter, nor one-half the number of illustrative engravings, that the London Magazine does." The Proprietors of the Glasgow Mechanics' Magazine, by publishing in the newspapers the former part only of our criticism, and in so far, therefore,grossly falsifying it, have sought to make it appear to the public as if we had voluntarily borne testimony to the utter inferiority of our work to theirs! But who could, for an instant, be deceived by so palpable an artifice? Of its liberality and consistency, in men professing to promote the interests of science and of truth, and indebted to us for the plan of their work, we shall say nothing. Communications received from-Tyne J. G.-H. S. H.-A Constant ReaderL.C.-J. H—-d-Capt. Hall-H. M. M. -Peter Palisade--Mr. LewthwaiteC. H.-A.J.-Focus-M. C.-Wm. Hoyle -Henry Christian-Indicator. ERRATUM, PAGE 271. For" D, a pulley to support the band, the band going under the roller;" Read, "D, a pulley to support the band. The band going under the roller." Advertisements for the Covers of our Monthly Parts must be sent in to our Publishers before the 20th day of euch Month. Communications (post paid) to be addressed to the Editor, at the Publishers', KNIGHT and LACEY, 55, Paternoster-row, London. Printed by MILLS, JOWETT, and MILLS (late BENSLEY), Bolt-court, Fleet-street. VOL. IV. Mechanics' Magazine, MUSEUM, REGISTER, JOURNAL, AND GAZETTE. No. 104.] SATURDAY, AUGUST 20, 1825. [Price 3d. NEW METHOD OF REGULATING THE MOVEMENT OF STEAM VESSELS, INVENTED BY J. AND C. CARMICHAEL. R 306 METHOD OF REGULATING THE MOVEMENT OF STEAM ENGINES. ACCOUNT OF A NEW AND COMMODI OUS METHOD OF REGULATING THE Captain Hall takes the liberty of sending to the Editor of the London Mechanics' Magazine, a Paper recently published (at his instance) by Messrs. James and Charles Carmichael, engine-makers, of Dundee, and will be happy if the Editor thinks it worthy of a place in his work. Captain Hall can assure him, that the beautiful contrivance described does its business most perfectly, and is so obviously applicable to every description of steam vessel, that he has no doubt it will be universally adopted when it becomes known. The ingenious inventors, with the modesty characteristic of true genius, not only never dreamed of taking out a patent, but were apparently unconscious of having accomplished any thing worthy of being made public. If their description, however, finds a place in the Mechanics' Magazine, it will require no farther advertisement. 128, George-street, Edinburgh, 29th July, 1825. "SIR,-In compliance with your request, we forward you a sketch of the machinery of the George IV. Twin Steam Boat, employed on this ferry, and we shall now proceed to give a description of that part of it invented by ourselves, the utility of which you have frequently witnessed, and which you are pleased to think may not be uninteresting to the scientific public. "The object of the contrivance we are about to describe, is to regulate the motions of the steam-vessel in a more easy manner than heretofore. By the simple motion of a small handle, or index, placed on a table, upon deck, in view and in hearing of the man at the helm, and of the master of the vessel, every movement which the engine is capable of giving to the paddle-wheel may be at once commanded. The vessel may be moved forwards or backwards, or may be retarded, or entirely stopped, at any given moment, by merely turning the handle to the places denoted by the gradations of a dial-plate. No skill is required for this purpose, so that the master himself, or a sailor under his directions, can perform the office as well as the ablest engineer. Thus, the confusion which frequently arises at night in calling out to the engineer below, is avoided, and any ambiguity, arising from the word of command being transmitted through several persons, entirely prevented. In point of fact, it places the engine as much under command as the rudder is an undoubted improvement upon the clumsy method of bawling out to the engineer below, who either may not hear, or may chance to be out of the way-circumstances which may lead to the most serious accidents. "The different parts of the machinery are not exactly arranged in the sketch as they are executed in said boat, but we hope that the principle will be better understood from having arranged them so as they can be better seen in the sketch prefixed. "The cylinder and jacket are cast in one piece, connected at the bottom, but altogether disconnected at the top when cast; the vacancy between the two is closed at the top by an iron ring, and hemp or rust packing in the joints. The steam from the boiler enters between the cylinder and jacket by the branch A, passes round the cylinder, and communicates with the side pipe, C, of the valve-chests, by the branch B, but cannot enter the cylinder when the steam-valves, DD, are shut. The eduction-valves, EE, are situate below the steam-valves. "The steam-valve rods work through a flax packing at FF, and are made hollow, to allow the eduction-valve rods to pass up the centre of them; they are also made air-tight by a flax packing at GG. "The valve-lifters, HHHH, are fast upon the lifter-rods, IJ, only one of which can be properly seen; the foot of the one farthest from the eye is seen at the rocking-shaft. One METHOD OF REGULATING THE MOVEMENT OF STEAM ENGINES. of these rods lifts the upper steamvalve and lower eduction-valve, and the other the lower steam-valve and upper eduction-valve. The lower steam-valve and upper eduction-valye are represented as lifted in the sketch. "The rocking-shaft, K, turns and returns upon its centre about 40°, and having two spanners (or pallets), L, projecting from it upon opposite sides, causes the lifter-rods and the valves connected with them to rise alternately. The lifter-rods fall by their own weight, and when the pallets are horizontal, all the valves are shut, and for an instant of time are at rest.. "The rocking-shaft receives its motion from an eccentric wheel, M, fastened to the crank-shaft. The fixing of this wheel, with relation to the crank and valves, is a point of considerable nicety, as upon this depends the opening and shutting of the valves at the proper time. "The eccentric rod, N, is supported on the crank-shaft by a projecting part on each side of the eccentric wheel, turned concentric with the shaft by the brass pieces, O. The four rods, P, pass through these brass pieces, and slide freely in them. This part is shown in the section at fig. 2, with part of the crank (or paddle) shaft, and the crank on one end. The other end of the eccentric rod is supported on the roller, Q; and as the crank-shaft turns round, the eccentric rod travels backwards and forwards a distance equal to double the eccentricity of the eccentric wheel; and as the said rod is connected with the rocking-shaft by the double-ended. spanner, RR, on one end of it, consequently the rockingshaft will travel from one extremity of its arch of motion to the other, in the same time that the crank-shaft makes half a revolution, or in the same time that the steam-piston travels from the top to the bottom of the cylinder, or from the bottom to the top. The steam-piston is represented in the middle of the cylinder, and as the lower steam-valve and upper eduction-valve are open, the piston must be ascending; and as the crank is connected with the opposite end of the walking-beam (or 307 lever), the crank will be descending. By the time that the piston has reached the top, and the crank the bottom, the rocking-shaft will be in that position where the pallets upon it are horizontal, and, of course, all the valves will be shut. But the momentum of the paddle (or fly) wheel carries on the motion, and immediately the two valves that were formerly shut, viz. the upper steamvalve and lower eduction-valve, are opened, and the steam presses down the piston with a force equal to the difference between its own elasticity and the elasticity of the uncondensed vapours below the piston. Thus the engines will continue to go, and the paddle-wheel to turn, in the direction of the dart. "But that we may endeavour to explain to you the method of stopping or reversing the motion of the paddle-wheel, all that is necessary is to shut all the valves; and this is effected by disengaging the eccentric rod from the spanner of the rockingshaft, and the valves all shut of their own accord, by the weight of the valves, lifter rods, &c., and the engine will stand and to set the engine agoing, either the one way or the other, is to lower the eccentric rod, to take hold of the double-ended spanner on the end of the rockingshaft, as represented on the sketch, and then the paddle-wheel will move in the direction of the dart, or lift the eccentric rod to the top of the spanner on the rocking-shaft, and then the paddle-wheel will nove in the opposite direction. The use of the sector-formed appendages, T, on the end of the eccentric rod, is to conduct the pins on the ends of the double-ended spanner into the notches adapted for them on each side of the eccentric rod; the form of which is better seen detached at fig. 3. "The hand-gearing, for starting or stopping the engines, is situated upon the deck of the boat, and all concentrated upon the top of a small table in view and in hearing of the man at the helm, or the master, who directs both, when coming to the quay. 1, a double-ended handle, which is upon the upright shaft, 2, on the 66 |