conds of time, before the weights had reached the lowest point of descent: this, it should be observed, was the mean result of three experiments, differing only in a very slight degree; which was a velocity equal to 45 feet per minute.

Upon substituting the wheel No. 10, which has paddles of the same shape, but with the sides left open, as in the ordinary wheels, the average of three experiments gave 25 feet, 4 inches of space, travelled over in 36 seconds, which is equal to a speed of 42 feet per minute.

In the wheel, No. 11, which has been applied to several steamboats, there is no other difference from the common wheel, except that the paddles, instead of being placed in the position of radii, are fixed at the angles shewn in the figure. The mean result of three experiments with this wheel, gave a speed of 45 feet per minute.

The wheel No. 12 is the common wheel, without spokes, or radiating bars, the paddles being soldered to the tin plate; three experiments were made with this wheel, with scarcely any variation in the results, the mean of which was sixty-eight feet and a quarter per minute.

The wheel No. 13 is the common wheel, left open, as usual, which averaged, upon three trials, a speed equal to 474 fcet per minute.

We were prepared to expect an advantage from enclosing the common wheel in the manner described; but the extraordinary increase of one-third in the effect never entered into our imagination. The result being of the highest importance to steam navigation, we have great pleasure in thus making it known to the public.

It will be observed, that, in all the experiments, the quantity of power and of resistance were uniform, and therefore that no very important error could have been made. Had we not made the experiments ourselves, we should have been very slow to believe; that, by this very simple and inexpensive alteration of the paddle-wheels, a boat, that is now propelled by her engines at the rate of 8 miles per hour, may make nearly twelve miles per hour!

TEST FOR COTTON IN CLOTH.-At a late sitting of the Royal Academy of Metz, the following method of detecting the presence of cotton in woollen stuffs was communicated. An ounce of pure alkali is dissolved in half a pound of water, and in this the suspected stuff is boiled for two hours. If the stuff is of pure wool, it dissolves entirely, and forms upon the surface a soap, which will pass through a fine sieve; but if, on the contrary, the stuff contains cotton, or any other vegetable fibre, it will not be entirely dissolved, but will show itself when thrown into the sieve.

GURNEY'S STEAM CARRIAGE.

THE misrepresentations that have been put forth to the public, through the medium of the newspapers, relative to Mr. Gurney's steam coach, induced the Editor of this Work, a few days ago, to send a copy of the annexed Letter

TO THE EDITOR OF THE TIMES.

SIR-As a constant reader of your invaluable Paper, I could not have failed noticing from time to time, a succession of accounts relative to the experiments made with Gurney's steam carriage, as it is called, for if the accounts alluded to be true, it might as well have been called your's, Mr. Editor, or mine, and as I shall presently show, that it is any-body's and every-body's.

Having been for many years the editor of a periodical work on mechanical science (the Journal of Patent Inventions), it may be presumed that I possess some knowledge of what has been done in matters of the kiud; and this knowledge, however limited, has caused me to regard with surprise, and even wonder, the impositions, that have been practised upon the public credulity, relative to the steam carriage in question, by writers who betray an entire, ignorance of the progress of improvements made in the steam engine, and of the various inventions of those ingenious men of the present day, who have given their attention to the construction of locomotive carriages.

I am, Mr. Editor, an ardent admirer, an absolute lover, heart and soul, of every thing connected with machinery, but above all with that noblest piece of mechanism, the steam-engine; and it is with delight that I anticipate the period when steam shall supply the place of horses, not only in propelling our carriages on the common road, but in drawing the plough and the harrow over the fields of the husbandman. If therefore I find fault with those writers who have heaped upon Mr. Gurney honours which do not belong to him, or who have ascribed inventions and discoveries to him, which were bequeathed to us by our fathers, or are the produce of living genius, let me not be suspected of a desire to damp the ardour of discovery, or to throw the slightest obstacle in the way of improvement. I am most ready to acknowledge that much credit is due to Mr. Gurney; he has persevered for nearly three years in making numerous experiments in locomotion, at an enormous expenditure of money; now if the testimonies of his friends (Mr. Herapath, Dr. Wilkinson, and others, who have deluged the diurnal press with their communications), are to be relied on, it would appear by them that Mr. Gurney had abandoned all his own contrivances, and adopted those of others instead; receiving from his friends the most fulsome adulation for so doing, as if the inventions were original and extraordinary. It is likewise but fair to acknowledge that Mr. Gurney has done more in VOL. IV,-No. 75. 1ST AUGUST, 1829.

M

and

public with steam carriages than any of his contemporaries, which I consider to be owing to his contemporaries not wishing to exhibit in public until they can do something better than Mr. Gurney has hitherto done; for I am not disposed to judge very favourably of his experiments, when I perceive that all the accounts hitherto communicated to the newspapers have contained great misrepresentations of the facts, or they have suppressed some of those necessary data by which alone a correct judgment can be formed. These remarks par ticularly apply to the last statement that appeared in the Times, of the Sth instant, being a communication from Mr. John Herapath, of Cranford, which I am desirous of replying to, rather than such au incorrect statement should remain unanswered.

That I may waste no more of your valuable space than is necessary to the exposure of the fallacy of Mr. Herapath's statements, and the defence of those numerous ingenious men whose inventions he has ascribed to Mr. Gurney, I shall pass over the prefatory observations and proceed to the examination of the " happy series of inventions,' by which he asserts" Mr. Gurney has obviated all the obstacles opposed to the success and safety of his carriage." Now had Mr. Herapath not attempted to prove this assertion, he would not have exposed Mr. Gurney and himself to the ridicule of every mechanic and engineer in the kingdom; for it unfortunately happens, as I will take upon myself to shew most clearly, that not a single invention out of the whole of the "happy series," described by Mr. Herapath, had Mr. Gurney any more to do with the conception of, than Mr. Herapath had with the building of the temple of Solomon, notwithstanding he appears so desirous of passing for one of that great man's disciples, by his repeatedly reminding the reader of his mathematical investigations," and his "scientific researches." Well may Mr. Gurney exclaim, save me from my friends, I will take care of my enemies."

Having stated that the great practical discoveries of Mr. Gurney had completely confirmed his" (Mr. Herapath's) "scientific researches," he proceeds "to kill two birds with one stone," by telling us what the " series of happy inventions" consist of, and this explanation shews us at the same time, what was the nature of his "scientific researches ;" for it must be quite evident to every informed person, that Mr. Herapath's researches in mechanism, have not been extended beyond the limits of Mr. Gurney's carriage. In that carriage he saw the inventions of Watt, and Hornblower, and Woolfe, and Trevethick, and Brunton, and Perkins, and Griffith, and James, and Hill, and Gordon, but knew them not ;-all was new to him ;-all extraordinary and peculiar, toto this celebrated invention:" yet the fact is demonstrable, that were the inventions of these men taken away, there would be nothing else left in the carriage, if Mr. Herapath's detail of them includes every thing; and I have no hesitation in saying, that nothing more, worthy of particular notice, was wanting to complete such a steam carriage as Mr. Gurney's is represented to be. Perhaps Mr. Herapath has been writing ironically

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 thein 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. s.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