208

And in the American Journal of Science, for April, 1828, the earth of the deep cuttings of the Welland Canal is stated to be removed on a like reciprocating plan-" the loaded descending teams drawing up the empty ascending ones." In America, the plan is claimed as a recent invention of one Oliver Phelps; but we believe there are few excavators in this country with whom it is not an old acquaintance. It is not long, since thousands in the metro polis must have seen it in practice in digging the foundations of the new London Bridge.--ED. M. M.]

DESCRIPTION OF THE GOLD COIN RE

PRESENTED IN NO. 320.

Sir, I have only just received the September Part of the "Mechanics' Magazine." If your correspondent, Mr. H. S. Guy, has not already received the information he wished, you can give the following:

-

The coin represented at p. 86, is the angel, first coined by Edward IV. in his 5th year. Henry VI. struck angels, but only during his short restoration, A. D. 1470-71; therefore, Edward's were the earliest.

The obverse has the archangel, Michael, trampling upon the dragon, and thrusting his spear into its mouth. The legend,

EDWARD DI GRA. REX ANGL. Z FRANC

The reverse bears a ship, with a cross for the mast. In centre, a shield with arms of England and France quarterly; on one side of the mast E, the initial letter of Edward, and on the other a rose. The legend,

PER CRVCE TVA SALVA NOS XRE REDEMTOR.

The angel is common; its weight should be 80 grains. Fineness, 23 carats 34 grains fine gold, and § grain alloy. It was made current at 6s. 8d., the value of the old noble, and hence sometimes called the noble angel. I am, Sir, Yours, &c,

Δ.

[A similar description to the preceding, but not so full, has been received from X.]

MINOR CORRESPONDENCE. Effects of Mercury on Gold-Sir, I was some what surprised in reading in No. 316 of your valuable work, the article headed "Deterioration of Gold by Mercury," at the effects there ascribed to mercury. I am a goldsmith, and have had sometimes to do with mercury, but was not aware it reudered the gold brittle. In every instance where I have seen the two substances in contact, instead of the gold retaining its colour, like the sovereign there mentioned, it was rendered of a whitish hue; but this whiteness was easily dissipated by the application of gentle heat. If the contaminated article is placed on a piece of warm metal, or over a lighted coal, you may perceive the evaporation of the quicksilver.

I am, &c.

W. S.

Consumption of Smoke.-Sir, In No. 324 of the "Mechanics' Magazine," under the head of Minor Correspondence, there is an offer by a Correspondent to communicate "a plan that will completely consume the smoke arising from a steam-engine fire, and well adapted for locomotive steam-carriages, as it will occupy but little room, and not require any extra flues."— I, Sir, am disposed to treat with the writer upon liberal terins; but I would first beg of him to state in one of your earliest numbers, whether the consumption of the smoke is effected without the consumption or abatement of heat in the fire. by the admission of cool air, which would produce that effect.

I am, Sir, yours respectfully,

A PROPRIETOR OF A FOUNDERY. Birmingham, Nov. 3, 1829.

A Correspondent at Weymouth announces to us the death, at that place, on the 6th instant, of Mr. John Harvey, aged 71, mechanic to our late-revered monarch, George the Third; one of the first proprietors of the Weymouth Water-works; late civil-engineer of the Bootle Water-works, Liverpool; and the original projector of the Breakwater for Portland Roads." -Mr. Harvey was a man of great ingenuity and worth, and much beloved and esteemed by all who knew him.

Self-loading Cart.-The Richmond Compiler contains a notice of a singular cart, invented by a Mr. W. Beach, of Philadelphia. It is de scribed as loading itself by means of one of the wheels, which is hollow, scooping up the earth as it revolves round. A cart of this construction is stated to be at work on the railroad, within a mile and a half of the Schuylkill river, near Philadelphia. It is worked by a mau and a boy; and removes and embanks in a day twice as much earth as is accomplished by three common carts and twenty men.

INTERIM NOTICES.

We are sorry we cannot give Mr. W. D. the information he requests respecting a certain work. Only four Parts of it, we believe, were published.

Communications received from H. J.-B. S. A.-R. C. Jun.-Henry D-O. C. F.—Brackstone-Mr. Baddeley-Mr Kingsnorth-A Constant Reader at Ludlow-E. W.-Mr. Gilman.

LONDON: Published for the Proprietor, by M. SALMON, at the Mechanics' Magazine Office, No. 115. Fleet Street; where Communications for the Editor (post paid) are requested to be addressed.

M. SALMON, Printer. Fleet Street.

210

AMERICAN RAILWAY-CARRIAGES.

The advantages of railway conveyance are beginning to be as sensibly appreciated in the United States as in this country. A rail-road of unexampled extent is now in the course of formation from Baltimore across the Alleghany mountains to the Ohio; and railways between most of the principal towns in the Union are stated to be also in contemplation.

The engineers of the Baltimore line were not long ago in England on a visit of inspection to our different railways; and as Jonathan is a shrewd observer, we may expect to hear before long of his having discovered many things in our practice to amend as well as imitate.

It must be confessed, however, that as yet the Americans are considerably behind us in all that relates to railways and steam-carriages; and in this as in other matters, incline but slowly to a reciprocal system. They treasure up all the good things devised on this side of the Atlantic, but favour us with very few of their own in return. Upwards of fifty different terro-locomotive plans have been brought forward within the last thirty years, but not more than three or four of these have been of American origin. The backwardness of the Americans in this particular line of invention is the more surprising, considering that it was in America the practicability of travelling by steam on land was first promulgated with due boldness. The English appear to be playing the same part precisely, in regard to steamcarriages which the Americans did in regard to steam navigation. Fulton, as every one knows, only carried into effect on the lakes and rivers of the western world, plans which he had previously seen reduced to practice, but, for want of adequate encouragement, laid aside in Scotland; and the Braithwaites, Stephensons, and Gurneys, of our own times, are but realising in England the "chimerical" projects (as they were called by the sages of Philadelphia) of the ingenious Philadelphian, Oliver Evans, who, thirty years ago, first pronounced travelling by steam on land a possible thing; so possible, that he did not hesitate to predict "the time would

come when carriages propelled by steam would be in general use, as well for the transportation of passengers as goods, travelling at the rate of fifteen miles an hour, or thirty miles per day!"

The persons who next to Evans have most distinguished themselves in connexion with terro-locomotion in America, are Mr. Winans and Mr. Howard.

Mr. Winans has invented a new description of wheels, which the Board of Engineers of the Baltimore Railway have resolved on adopting, in which friction is so much reduced, that if we may credit the statement of a Mr. Sullivan (the partner of Mr. Winans), in the Journal of the Franklin Institute for April last, a steamcarriage with these wheels will draw nearly four times the weight it could with wheels of the common construction. Mr. Winans has obtained a patent for his invention in the United States, and he is now in this country soliciting a similar privilege for Great Britain. We have perused Mr. Winans's American specification, and had the pleasure of examining a waggon with wheels on his principle, which was exhibited at the late railway competition, as also of witnessing some trials made with it; and we are well satisfied, that the reduction of friction realised, though by no means so great as Mr. Sullivan has represented, is at least so considerable, that great gain, both in point of speed and economy, must result from their adoption.* As Mr. Winans has not

yet enrolled his English specification, and as we believe it will include some material improvements, which have been only devised since the patentee has been in this country, we shall not say more at present of the principle on which the wheel is constructed, than that it consists in an application of the aid of friction-rollers, or wheels, at once ingenious and simple, and, as far as we are at present aware, perfectly original.

Mr. Howard is the inventor of the railway-carriage of which we gave a description, with drawings, in our 306th Number. The chief peculiarities of that carriage were the introduction of a jointed perch, for the purpose of enabling it to take curvilineal turns with ease, and the adoption of friction-wheels on a plan different from that of Mr Winans, and by no means so good. Mr. Howard has since produced another carriage, in which he professes to have greatly improved his method of enabling carriages to travel on curved rails; and

Miles per hour, 43

1lb. with 617, kept it moving 1lb.with 800, kept it moving. When 121b. 12 oz. and upwards were used to bring the carriage and load forward, it invariably gained in speed.

"On the whole, the results were highly satisfactory; and from them it would appear, that a horse's work on the rail-road, at a slow speed, may be brought to approximate much nearer to his work on a canal, than perhaps had been generally imagined. One point seemed to be fully established, that this principle has greater advantages under a quick speed than under a slow one; for, when considerable speed was given at first, by other power, the speed was better kept up or increased by the respective weights than when tried under a slow speed."-Liverpool Chronicle.

211

this invention we now proceed to describe.

Figure 1, on the front-page of our present Number, exhibits a perspective elevation of Mr. Howard's "Improved Locomotive-Carriage;" fig. 2, (next page) a back view; figs. 3 and 4, parts of the wheels to illustrate more clearly their peculiar mode of action. The same letters of reference refer to the same parts in figures 1 and 2; and to make the peculiar improvements which Mr. Howard has here introduced the more easily recognised, his friction-wheels, and some of the minor details of steam apparatus, are omitted.

The first desideratum which Mr. Howard has made it his study to accomplish in this engine, has been to render the axle-trees capable of adapting themselves to the curve of the road, so that a perpendicular plane drawn through the centre of the axle may be normal to the curve. His arrangement for this purpose we shall give in his own words:

"The usual beam fastened by jaws to the axles, is divided in the centre, and a tooth and socket permits one end to play in the other. This contrivance, as shown in my improved railway-carriage, obliges the hindwheels to follow in the track of the fore ones. Besides this, there is a beam extending from one axle to the other, and traversing on the centre of each, round a strong bolt. To this heam, the boiler A, with the cylinders BB, are attached. The boiler, indeed, may be made to answer the purpose of this beam, by placing it upon beds HH, beneath which the axles GG move horizontally around centre bolts. At each side of the boiler, and attached to the axles, and moving with them, are perpendicular supports or guides DD, with openings for the vertical motion of the ends of the shackle-bars OO of the piston-rods; each pair of supports, or guides, being connected at the top by an iron bar, in the centre of which is a bolt connecting it with an iron frame EE, passing lengthwise from each extremity of the boiler to which it is fastened, and which keeps the supports, or guides, in their vertical position. This last bolt is directly over the bolt of the waggon-bed, as well as over the