of travelling by steam on common roads in an ascent is diminished, the advantages of steam over horse power are lost. The efficiency of horses in draught is rapidly diminished as their speed is increased; while, on the contrary, the weight, which could be carried or propelled, at any given velocity, by steam, could not be more cheaply conveyed, were the speed decreased to that of the slowest waggon.

As speed, therefore, is the cause of greatly increased expense, where horses are used, while with steam it is comparatively unimportant, it is probable that the latter will be chiefly resorted to when rapidity of conveyance is required. Mr. Gurney considers, that under four miles per hour, horses can be used in draught more economically thau steam. Should it, however, be deemed profitable to convey heavy goods by steam carriages, the committee recommend that there should be as little interference as possible with the number of carts employed, as the ef fect on the surface of roads would be infinitely more injurious if heavy loads were placed on a single cart, than if the same weight were divided over several. The committee recommend, that where car. riages containing heavy goods alone, are propelled by steam, the weight of the load should be charged, without reference to the number of carts on which it may be carried.

As a horse can draw from 20 to 40 cwt. on roads, they propose that each 20 cwt. of load conveyed in a steam carriage, should be chargeable at the same rate of toll as one horse drawing a cart.

A charge on weight is not so objectionable where goods are conveyed at a slow rate, as when speed is alone required.

In conclusion, the committee submit the following Summary of the Evidence, given by the several Witnesses, as to the progress made in the application of Steam to the purposes of draught on common roads.

Sufficient evidence has been adduced to convince your committee

1. That carriages can be propelled by steam on common roads at an average rate of ten miles per hour. 2. That at this rate they have conveyed upwards of fourteen passengers. 3. That their weight, including engine, fuel, water, and attendance, may be under three tons.

4. That they can ascend and descend hills of considerable inclination with faciolity and safety.

5 That they are perfectly safe for passen

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properly constructed, nuisances to the public.

7. That they will become a speedier and cheaper mode of conveyance than carriages drawn by horses.

8. That, as they admit of greater breadth of tire than other carriages, and as the roads are not acted on so inju riously by the feet of horses in common draught, such carriages will cause less wear of roads than the ordinary vehicles, drawn by horses. 9. That on some roads tolls have been imposed, which would be prohibitory of their being used.

MINUTES OF EVIDENCE.

Aug. 3, 1831.

Charles D. O. Jephson, Esq., in the Chair.

Mr. Goldsworthy Gurney examined. Is patentee of a steam-carriage to be used on public roads. Has made experimental journies with it to Edgeware, Stanmore, Bath, and other places; and has been lately running coaches on this plan, as public stages, between Gloucester and Cheltenham. They were stopped for about three weeks in consequence of an accident to one of the axle-trees; but they were to begin again about this time (Aug. 3). Produces six different drawings explanatory of his progressive improvements in steam carriage machinery. It being a prevalent opinion, that, the bite or friction would not be sufficient to propel a carriage along a common road, feet or propellers were proposed to be used; but found, on trial, that they were rarely wanted. Applied the power immediately to the two hind-wheels, through a crank, in the common mode of a steam-boat, and found this sufficient to take a carriage up Highgate-hill, Stanmore-hill, and Brockley-hill. It was afterwards found, that by wire-drawing the steam, as it is called, the bite of one of the hind-wheels only was sufficient for all common purposes. A carriage, with only one wheel attached to the axle, ran to Barnet, and up all the hills to that place, in 1827. It was, in consequence of this, thought advisable to have two carriages; one of light. weight, to carry the engine, or propelling power, and another to be drawn by that carrying the load. It was a carriage of this (double) description that went to Bath, and over all the hills between Cranford-bridge and that city. It returned with only one wheel attached to the axle: the other carriage, by means of attachment, having broken in the first onset. Performed the 84 miles between Melksham and Cranford-bridge in 10 hours, including

stoppages. One principle has been adhered to in the boilers, but there have been various changes in the mechanism. The chimney, and a variety of other disagreeables, have been removed. Has contrived to reduce the total weight of his steam-carriages from 4 tons to 35 cwt.the power remaining the same. The carriage which was running between Gloucester and Cheltenham is said to weigh nearly 3 tons, but it ought not to weigh more than 45 cwt.; it was built principally under the superintendence of another person. Has carriages now building that will not weigh more than 35 cwt. Thinks the weight will be still farther reduced as improvements go on. Has one now building to do the work of one horse, and carry two or three people, which he expects will not weigh above 5 cwt. Thinks journies by steam carriages would be most conveniently divided into 7-mile stages. For one weighing 35 cwt., 3 bushels of coke would be required for that distance; and if the roads are bad, 70 gallons of water

700lbs. weight; if good, about onehalf that quantity. The hind-wheels are about 5 feet in diameter; the fore, 1 foot less; and thinks these proportions the best for general use. By taking a wheel of 5 feet diameter off, and putting on one of 2 feet, inches, the engine would be doubled in power, but lose one-half in speed. The tire of the wheels is in no case less than 2 inches; in some instances about 34. It appears, from experiment, that rather less power is required as the width of the tire is increased, but the difference is so slight as to be scarcely perceptible. Witness's ordinary travellingengine is nominally of 12-horse power. To work 8 hours it requires 32 horses for a common stage-coach; an engine propelling the same weight for 8 hours, should therefore be considered a 32-horse power, according to the rate laid down by engineers; but this is not true as to locomotive-engines. Thinks a steam-carriage, weighing 35 cwt., should be equivalent to 3 horses' work always; that is, in every stage it will displace 3 or 4 horses, and about 30 horses in the 8 hours. whole carriage is on springs. The weight of an ordinary stage-coach is from 18 to 24 cwt., and it will carry about 18 passengers. A steam-carriage to do the same work should be equal in weight to that of 4 horses 2 tons; the carriage drawn by it would weigh the same as one drawn by horses. Has here supposed a horse to weigh about 10 cwt.; but some weigh more than that-as much as 16 cwt.others less. Conceives that steam-car

The

riages do no more injury to roads than any others of the same weight. Has compared the loss of iron from the tires of the wheels with the loss from other carriages running the same number of miles, and found the loss nearly the same. When the steam is wire-drawn, the wheels never slip; but if the steam is laid on suddenly, it acts on the wheels as if they were struck with a hammer, and they will not move forward. They may some times slip for an instant at starting, but never on the road unless overweighted. Coke is the fuel employed, and of course there is no smoke; were coals used, there would be. Is frequently obliged to let off steam, but not openly; it is allowed to escape from the safety valve into a chamber peculiarly constructed, which prevents any annoyance from it. Has not observed that horses are more liable to be frightened by passing steam carriages than passing any others. Has seen horses shy often, never saw one make a dead stand. When the propelling wheel gets into a rut, it is sometimes necessary to attach a second wheel to the axle ; but has never known a situation in which a carriage with both wheels attached would not get out. Has seen a carriage in a clay pit, eight inches deep, propel itself through, having sunk through the upper surface of gravel in a yard. When the road is between half wet and half dry, the wheels are most apt to slide; and two wheels are then necessary to propel a weight which one would suffice to move in very wet or very dry weather, Two wheels are also frequently required in going up hill. Obstructions from the wheels encountering stones seldom occur. Has blocked up the wheels of a carriage with square pieces of wood 4 inches in diameter, and started it when so blocked up. In proportion to the size of such obstruction there is a liability in the crank to break; the axles are made in consequence unusually large. The throw of the crank is half the diameter of the stroke of the engine, which is between 16 and 18 inches. The diameter of the cylinder is about 8inches offering 64 circular inches area on the pis ton. The sort of accident to which steam carriages are most likely to be exposed, is the derangement of the pumps; but the result would merely be, that the carriage would stop. The tubes of the boilers burst very often at first, but has now remedied the probability of such an occurrence. The first tubes were iron gas tubes, not welded, but simply "butted together; the consequence was that, under any great pressure, the seams opened. The edges were then overlapped and

welded from end to end; and now the tubės are not subject to such accidents. The tubes are of iron, and from half an inch to two inches in diameter; thinks the best size is one inch; they are proved to about 800 lbs. pressure, and thinks they would bear 2000 lbs. Has never been able to burst one when well made, overlapped, and welded. The average pressure on the boiler per square inch, at the ordinary rate of travelling, is about 70 lbs.; works sometimes up to 100lbs. and 120 lbs.; but only in cases of great emergency. The greatest pressure at which the engine would be ever probably worked, would not be more than 130 lbs.; the safety valve blows at 70 lbs. to the inch; it is generally on the lift, on a level hard road; on the engine (the piston) the pressure is often not more than 20 lbs. to the inch. The tubes are about 4th of an inch thick; the working cylinder about 4 of an inch, with ribs round it. Has tried cylinders of gun metal, but finds cast iron answers best. Has always experienced the greatest facility in guiding the carriages; can instantly throw the steam on the reverse side of the pistons, and stop within a few yards. It might be supposed that the momentum would carry the carriage forward, but it is not so; the steam brings it up gradually and safely, though rather suddenly. If going 8 miles an hour, could stop within 6 or 7 yards. The drawing and drawn carriages are so connected, that the forewheels of the latter follow the tracks of the hind wheels of the former, although making a circle of only 15 feet diameter, which is a singular property. Could turn both carriages in a circle of 10 feet, the inner diameter. Even when going at the rate of 8 miles an hour, thinks he could turn them in a circle of 100 feet diameter. The carriage drawn with its load should never exceed 3 tons: nor the drawing carriage about 2 tons, or 50 cwt. Never met (personally) with any serious accident, except when going up Highgatehill, five years ago. Went up the hill contrary to the expectations of every person present, and the workmen were so delighted, that in returning down the hill they neglected to lock the wheel; it became, therefore, difficultly manageable, run against a stone, and was upset. The accident before alluded to as having occurred at Cheltenham-namely, the breaking of the axle arose from peculiar circumstances. New stones had been laid in a hollow of the road, to the depth of about 18 inches; the carriage had gone through it twice with 20 passengers; the third time the axle was fractured from

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the extra force applied to get it through. Was informed that two waggons and two coaches were stopped in these stones at the same time, and were obliged to exchange their horses to get through. The fire-place and boiler are so constructed, that he believes it impossible that a carriage should ever catch fire. Ou the roads in the neighbourhood of London, the wear of the tires of wheels is less by two-fourths than that of horse-shoes. A steam carriage runs much easier on pavements than on ordinary gravelled roads they require then only a quarter of the power. But has no doubt whatever that steam-carriages may be brought into operation on turnpike roads, without any alteration in those roads. The tolls on steam carriages might be regulated on the following plan. An iron horse, of the same weight as one of flesh and boues, should pay the same toll; so that taking one horse to weigh 10 cwt., the steam carriage should pay the toll of one horse for every 10 cwt. it weighs. Does not, however, admit, that the same weight when carried on four wheels will do as much mischief as on four hoofs. The Liverpool and Prescot Road Bill, lately passed, charges a toll per horse power; but this is difficult to determine. Witness's objection is, that if the horse power is taken as the nominal engine horse power, a steam coach would have to pay 21. 88. where a stage coach pays only 4s. On the Edinburgh and Bathgate-road again, the tolls are regulated to the weight, and an engine of 3 tons (the usual weight of a loaded 4-horse stage coach) would have to pay 1. 7s. Id., when 4 horses would have to pay only 5s. By the Ashbourn and Totness road bill, 21. would be charged on a steam carriage and the carriage attached, being 5s. on each wheel, while 4 horses would have only to pay 3s. The toll charged between Cheltenham and Gloucester is 5s. 6d. ; for a 4horse coach it is only 2s. 8d. On the Teignmouth and Dawlish road, the proportion is 12s. to 2s. The instance most favourable to steam carriages is, that of the metropolis roads, where one shilling is charged for four horses, and two for a steam carriage drawing another behind it; but the witness complains of that because it limits him to a particular kind of carriage. Mentioned before that he is building one to carry two or three persons, that will not weigh more than 5 cwt., and should think a toll of 2s. for such a vehicle excessive. There is no reduction if a carriage is no bigger than a wheelbarrow; because it is propelled by machinery it is charged double. Produces 54 private

bills, which have been introduced during the present session, in which steam-carriages have been made special objects of taxation; some of which have passed;" ánd understands there are others. Taking the average of tolls throughout the country, it appears that 3-8ths are imposed on the horse, and 5-8ths on the carriage'; that is, a horse not drawing pays three halfpence-and when drawing, sixpence. Suppose, therefore, a steamengine weighs 10 cwt.-the weight of a horse-it should pay at the same rate as a horse when drawing and when not drawing. A 10-cwt. steam-engine cannot propel more than one horse can draw. If the weight exceeds 10, and not 20, it should pay as two horses, and so on. A horse will sometimes draw 30 cwt., but 15 cwt. is the usual draught. Thinks that when the wheels are wider than 4 inches, the tolls should be proportionably diminished. Thinks it possible steam-power might be applied to move great weights at a slow pace, as well as small weights with rapidity; but has found that when you get below a rate of 4 miles an hours the expense in fuel is greater than that of horses. If the rate exceeds 4 miles, then the steam-carriage is cheaper, and it gains in cheapness geometrically over horses as you get up. Anticipates that the principal advantage to be derived from steam. carriage will be in the conveyance of passengers; which may be effected at onehalf the present expense, and in less time. Has run steam-carriages safely 18 and 20 miles an hour; 12 is perfectly practicable; and there is no difficulty or danger in guiding the carriage at this rate. The wheels are cylindrical, and must be so, because they turn with the axles. (To be continued.)

MINOR CORRESPONDENCE.

Flight of Insects." An Entomologist" begs to refer the correspondent who made an inquiry, some time ago, (vol. xvi., p. 47) respecting the locomotive power of insects, to Durckheim's Anatomie Comparée des Animaux Articulés.

Steam Carriages." In the Report of the Select Committee on Steam Carriages, mention is made of a steam-carriage having actually ascended an inclined plane rising 1 in 6, and at the rate, too, of sixteen and a half miles per hour!!! I should like to know whether this was by the aid of Saxula's long crank, about which so much has been said in the pages of the Mechanics' Magazine?"-J. E. [Not, we apprehend, by this or any other long crank, but by means of a very, very long bow.-ED. M. M.]

Cleaning Rusty Knives." Mr. Winterton's me thod of cleaning the rust off knives, p. 412, is rather a roundabout one. The handles must, of course, be taken off before the knives are made red hot. After

all, I believe the readiest, and, at the same time, most effectual cleaner, is the cutler's emery-wheel." -Ibid.

"Has Mr. W. ever tried the effects of his receipt on a set of knives (his own, property) worth £5 or £10? If so, I trust he will favour us with the result. I am inclined to suspect it would injure materially the temper of the knives."-John Edwardson.

*

National Repository." Your prediction respect. ing this absurdly-named establishment is now about to be fulfilled-Government having determined on converting the gallery to the purposes of a cholera hospital." J. E.

Useful Knowledge Society's Treatise on Commerce. -"An English Reader" complains of the author of this Treatise (reputed to be Mr. Mac Culloch) for quoting German books, through the medium of French translations. "For instance: he gives extracts in French from Schmalz, on Political Economy; a work originally written in German. It has been published about twenty-four years ago (I believe). but till within the last four years Mr. Mac Culloch has never said a word about it. And why? Because it is only four years since it was translated into French. Since Mr. Mac Culloch found the original German of this work such an obstacle to his availing himself of its contents, it is surprising he should not have shown some fellow feeling for those of the thirty-six millions who are as ignorant of French as he is of German. What would have become of him, if Malthus and Ricardo had thought fit to chequer their pages with German, after his own pedantic fashion? It is to be remembered, too, that the Useful Knowledge Society profess to write for the information of the middling and lower classes, chiefly among whom a knowledge of French is not as yet a very common accomplishment."

INTERIM NOTICES.

J. E.-Not at present; but see notice on the subject in No. 432.

E. H.-The two previous communications mentioned, are on our list for insertion.

Philo-Mechanicus-An early place.

Amanuensis-The letters sent" about two months ago," never came to hand.

"Henry" will find a packet for him at our publisher's,

Communications received from Mr. Deakin-Mr. Russel-A Foreigner-T. M. B.-Y. Z.-T.-Saxula -Horatio-J. E.-Telus-Mr. Gooch.-Mr. Baddeley.

LONDON: Published by M. SALMON, at the Mechanics' Magazine Office, Wine-Office-court, (between 145 and 146) Fleet Street, where Communications (post paid) are requested to be ad. dressed. Sold by G. G. BENNIS, 55, Rue Neuve, St. Augustin, Paris. GRAY and BOWEN, Boston (U. S.)

M. SALMON, Printer, Fleet Street.