against Mr. Gurney's machine, for the effect of such praise on the minds of well-informed persons, is to depreciate its value and interest. The present carriage, Mr. Herapath says "differs from the earlier carriage, in several improvements in the machinery, suggested by experiment; also in having no propellers; and in having only four wheels instead of six; the apparatus for guiding being applied immediately to the two fore-wheels, bearing a part of the weight,i nstead of to two extra leading wheels bearing little or none."

The reason for not using the propellers may be, that he is not permitted to use them, by a previous patentee, Mr. Gordon, who in 1824 patented a very similar contrivance, which was an improvement upon the original invention of 1813, by Brunton. It is a circumstance worthy of remark, that in the prospectus issued by Mr. Gurney, of his first steam carriage, between two and three years ago, he asserts that the propelling by means of levers, acting against the ground in the manner of horses legs and feet, was the only efficient mode, as the following extract from that document will shew.

"The great difficulties appear to have arisen, first from the unmanageable weight of the steam engine and apparatus, and secondly from the imperfect or wrong application of the power; for, with a few exceptions, they have invariably applied the power to the wheels, forgetting that these being passive, are unequal in resistance to propel any weight against inclined planes over bad or uneven roads. These difficulties, whether arising from weight, or application of the power, appear from experiment to be completely removed, for instead of the power being, as hitherto, applied to the wheels, propellers or feet are made to connect the engine with the ground, in such manner that the engine propels itself and the carriage with great rapidity.'

Now, however, Mr. Gurney finding from further experiment, that all his contemporaries were right, and that he only was wrong," he abandons the propellers, applies his power to the "passive" wheels, and then Mr. Herapath's" researches" leads him to proclaim it as one of Mr. Gurney's happy inventions!

With respect to the employment of four wheels instead of six, every body knows this is only copying the plans of others, and in the application of the guiding apparatus to the foremost of these,"bearing a part of the weight" the "improvement" is equally original; for let it be remembered that Mr. Gurney was the only locomotionist that ever committed that ridiculous error of applying the guiding apparatus to any other; and in thus abandoning that silly contrivance of the "pilot wheels," (which was the name given to it, and was the theme of much foolish admiration); and in adopting in lieu the plans of his contemporaries, Mr. Herapath considers Mr. Gurney to have added another to the "series of his happy inventions. I pass on to the next. "No person can conceive," says Mr. Herapath, in an ecstacy, "the absolute control this apparatus gives to the director of the carriage, unless he has had the same opportunities of observing it which I had in a ride with Mr. Gurney. Whilst the wheels obey the slightest motion of the hand, a trifling pressure of the foot keeps them inflexibly steady, however rough the ground,"

This steering apparatus, (as illustrated in the recently published drawing of Mr. Gurney's carriage) was previously adopted by Burstall and Hill, Gordon, Anderson and James, Hague, and various others; but it was found to have great defects; and those of the above-mentioned gentlemen who are proceeding with their carriages, have, I believe, abandoned it, and are substituting more efficacious contrivances. The defects consisted, in having so limited a range as to render it impracticable to make very sharp turnings, and in being so deficient in power, as to require the arm of a Hercules to turn it at all, when upon rough ground. (It is true, that Mr. Gurney's has a very long lever, which reduces the range in the ratio that it increases its power.) When Mr. Gurney finds out these disadvantages, and, abandoning the contrivance, shall take up the improvements mentioned above, I doubt not Mr. Herapath will seize hold of them, in like manner, to swell the "series of happy inventions." With respect to keeping the fore-wheels' steady by pressure with the foot, Burstall and Hill did this, in the same manner, by forcing two friction plates into contact. The next improvement is thus described.—

"To the hind axle, which is very strong, and bent into two cranks of 9 inches radius, at right angles to each other, is applied the propelling power by means of pistons from two horizontal cylinders. By this contrivance, and a peculiar mode of admitting the steam to the cylinders, Mr. Gurney has very ingeniously avoided that cumbersome appendage to steam-engines, the fly-wheel, and preserves uniformity of action by constantly having one cylinder on full pressure, whilst the other is on the reduced expansive.'

It does not appear that the "scientific researches" of the writer had enabled him to discover that, "this contrivance," has been in common use above thirty years. Trevithick and Vivian had a patent Engine in 1802, in which cranks at right angles were employed; but the crank was thus applied much earlier than that period, probably nearly as far back as the first invention of the crank in 1736, by Jonathan Hulls; at all events, it has been used in almost every steam-boat since his time, and is now universally applied in steam navigation, and very extensively for other purposes; but especially in almost every steam-carriage prior to Mr. Gurney's. Then, as to the results of this brilliant discovery, by which Mr. Gurney "has very ingeniously avoided that cumbersome appendage to steam engines, the fly-wheel, there cannot be a doubt in the mind of any mechanic, that Mr. Gurney would rejoice exceedingly if he could find convenient means of applying it. Mr. Herapath would thus make it appear, that Mr. Gurney was like the fox in the fable, who, when he could not with all his cunning, find means to get at the clusters of delicious grapes that hung over him in the vineyard, shook his head at them, swore they were sour, and would have nothing to do with them.

With regard to the mode of working by expansion, the "scientific researches of Mr. Herapath ought to have informed him, that this was invented by Watt, in 1769, that Woolfe patented his improvements in 1804, and that subsequent engineers had much sim

plified, and, I might almost say, had perfected the principle. The mode, as described by Mr. Herapath, is indeed so common, that I make no doubt a thousand engines are at the present moment being worked by it; and it has besides been used in all steam-carriages prior to Mr. Gurney's. In explaining the advantages attending this pretended novel mode of Mr. Gurney's, the writer has only incorrectly repeated what is explained much better in every work or tract on the subject, that has been published during the last 20 years. So much for this improvement." Now for the next :

Firmly fixed to the extremities of the axle, and at right angles to it, are the two " carriers (two strong irons extending each way to the felloes of the wheels). These irons may be bolted to the felloes of the wheels or not, or to the felloes of one wheel only. Thus the power applied to the axle is carried at once to the parts of the wheels of least stress-the circumferences."

I am most ready to admit, Mr. Editor, that so bungling a contrivance as this was never before applied to a steam-carriage, though I remember having seen it applied to a dung-cart by an old farmer, who nailed a board across the dislocated wheel, to keep it together in its journey to the wheelwright's. Would Mr. Herapath have us suppose, that Mr. Gurney is incapable of making a proper wheel, one in which the periphery, or felloes, shall be as firmly united to the centre, or nave, as if it were a solid body? I have a greater respect for the talents of Mr. Gurney, than to suppose it possible; but admitting his incapacity to do this, as Mr. Herapath insinuates, is there not Theodore Jones's patent suspension wheel, which answers all these conditions, combined with lightness and elegance? If Mr. Herapath should still insist, that these clumsy iron bars, so funnily surnamed "6 carriers," shall be inrolled among the "happy series,' I dare say the old farmer above-mentioned will very good-naturedly allow him all the honour and profit arising therefrom.

By this artifice," Mr. Herapath continues, "the wheels are required to be of no greater strength and weight than ordinary carriage wheels." I would here enquire whether it is not very strange to object to a wheel, on account of superior strength; unnecessary weight is certainly objectionable, and, by putting heavy iron bars across a bad wheel, one would imagine that Mr. Gurney was rather seeking for weight than strength.

Mr. Herapath next tells us, that these wheels "turn freely and independently on their axles; but one, or both of them may be secured as part and parcel of the axle, as circumstances require." Messrs. Burstall and Hill patented this contrivance in 1825; their specification describes two excellent methods of effecting it, and the object is stated to be," the causing the wheels to be impelled, when the axle revolves, and at the same time allowing the outer wheel, when the carriage describes a curve, to travel faster than the inner one, and still be ready to receive the impulse of the engine, as soon as it comes to a straight course.

The next mentioned invention of the " described:

happy' series, is thus

"Beneath the hind part drop two irons with flat feet, called, shoe-drags. A well-contrived apparatus, with a spindle passing up through a hollow cylinder, to which the guiding handle is affixed, enables the director to force one or both drags tight on the road, şo as to retard the progress in a descent, or, if he please, to raise the wheels off the ground."

A contrivance closely resembling this, has been for several years in use in the Diligences of France; the same thing was adopted, or was proposed to be adopted, in Mr. Gordon's locomotive carriage, and was actually applied and patented by Viney and Pocock, in their Kite Carriage, or Charvolant. Contrivances for the same purpose have been adopted in all the steam-carriages; but those I have particularised, have so close a resemblance to Mr. Gurney's apparatus, that Mr. Herapath may fairly class it among the "happy series." The utility of this apparatus is, however, so truly extraordinary, that I trust your readers will excuse my repeating Mr. Herapath's observation; he says

"The propulsive power of the wheels being by this means destroyed, the carriage is arrested in a yard or two, though going at the rate of 18 or 20 miles an hour."

I cannot, Mr. Editor, boast of my "scientific researches," or "mathematical investigations," like Mr. Herapath, but if he can stop without destruction, a ponderous body like a steam-carriage, so suddenly, whilst moving with the velocity of 20 miles an hour, I must regard him as a much greater man than my old acquaintance Gulliver, who, when the artillery of a fortress was opened upon him, faced the terrific shower of cannon balls, caught them in his hands, and flinging them back again, destroyed the fortifications and his enemies together!

"On the right-hand of the director lies the handle of the throttle-valve, by which he has the power of increasing or diminishing the supply of steam ad libitum, and hence of retarding or accelerating the carriage's velocity."

Now, this has been applied in all other steam-carriages in a similar way, and is the well-known common appendage to all stationary engines for the same puspose.

The next observation is

"The whole carriage and machinery weigh about 16 cwt. and with the full complement of water and coke, 20 or 22 cwt. of which, I am informed, about 16 cwt. lie on the hind wheels."

If this statement be correct, Dr. Wilkinson's must be otherwise; and from the candour of the latter gentleman, and his abstaining from praising his friend for what did not belong to him, I certainly rely most upon his statement. Dr. Wilkinson tells us, that there are two cylinders, each of 6 inches diameter, and having a stroke of 20 inches. Now, I confidently appeal to any engineer, whether it be possible to construct cylinders of the magnitude mentioned, with boiler sufficient to generate the steam required to work them, the framings and the casings, the pumps, condensers, flues, chimney, and all the et cetera of the engines, the guiding and friction apparatus, the drags,

the "carriers," the four wheels, body, frame, perch, &c. at less than 30 cwt. (and I should not be surprised to learn that the actual weight was above two tons). There is then the coals and water to add, for which Mr. Herapath adds from only 4 to 6 cwt. Of the correctness of this, we shall be able to judge by comparing it with the data furnished by Dr. Wilkinson, who says that,

"One bushel of coke will suffice for 2 miles, and 1 gallon of water is consumed each minute; hence, every 8 or 10 miles, a fresh supply of water is required, and every 20 or 30 miles, coke." According to the most favourable statements of Mr. Gurney's journey from Melksham, ten miles were performed in about an hour and a half, or 90 minutes; and as a gallon of water, which weighs 10 lbs. exactly, is required for each minute, here are 900 lbs. of water, besides the weight of the tanks, which must be 100 more. Then if we take the coke for 30 miles, that is 15 bushels, which, at 45 lbs. per bushel, is 675 lbs. therefore without calculating the weight of the receptacle for coke, we have, in fact, a greater weight for the fuel and water alone, than Mr. Herapath tells us is "the whole weight of the carriage and machinery." The vast difference between these statements shews how little may be relied upon them; and it is deserving of notice, that none of the writers who have communicated to the public papers, have told us the important fact, that the supplies of coke and water were carried by another carriage, drawn by horses, on the journey from Melksham.

To follow Mr. Herapath through his argument on the capabilities of this machine, arising out of calculations made from erroneous data, is a task to which neither the patience of your readers or my time will permit. I therefore propose to notice briefly only two more of the happy series" (which Mr. Herapath recapitulates towards the close of his letter, and dwells upon with poetic fervor, lest his readers should forget them) and then conclude my epistle.

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One of these relates to the apparatus for reversing the motion of the engines, and thereby causing the carriage to go backwards, which is uniformly applied to steam-boats, for reversing the paddle wheels, and has been applied in every steam carriage constructed prior to Mr. Gurney's. The next and the last remarks. I shall make relates to his boiler, or steam generating apparatus, which Mr. Herapath does not condescend to acquaint us with the structure of; but, on reference to Dr. Wilkinson's letter, we find the following description.

"The boiler, or generator, as it is termed, consists of about twenty gun-barrels, three feet in length, communicating at each end with an iron tube, by which arrangement a general communication is effected with every tube, and the barrels are about an inch from each other, and serve as a grating for the fire above, which is fed with coke from the inside of the carriage; a second fire is placed under the barrels, and supplied from the outside; so that this chain of tubes is placed between two fires; these tubes are completely filled with water, so that whatever degree of heat is employed, the water retains its fluid form, and does not assume a vaporific character before its liberation from the heated barrels; if any additional portion