ing of the two motions ought to be attended to; were that done, there would probably be no use found for oil and emery afterwards. On the whole, your committee beg to recommend this interesting communication to the attentive consideration, and favourable notice, of the Society. EDWARD SANG, Convener. Edinburgh, July 18, 1838. HYDRODYNAMIC RAILWAYS. IMPROVEMENT IN CANAL TRANSIT. Sir,-In your excellent publication, vol. xxiii., there is a very interesting article headed" Hydrodynamic Railway," the production of Mr. Herron, of North America. The writer of the article recommends the use of water wheels as a cheap method of transport upon railroads or ashler stone roads. I have spent many hours and days in studying the subject, and I am of opinion he is quite right, except on one point, viz., the allowance to be made for the friction of the rope. He supposes 600lbs. a power sufficient to overcome the friction of a rope four miles in length running upon rollers; that is, two miles of road, with a double or endless rope; the loads being 50 tons and moved at the rate of 10 miles an hour in this case the friction of the rope would be much more than 600 lbs. By referring to a book published in Liverpool in the year 1830, by Robert Stephenson and Joseph Locke, civil engineers, at page 47 it is stated that the friction of a rope one mile in length is 382 lbs. ; and, of course, for four miles 1528; the circumference being 4 inches, and the weight of four miles 18,368 lbs., the friction being 1-12th of the weight; and the loading is proposed to be 52 tons. It is scarcely necessary to say that this thickness of the rope would do for either a load of 50 or 52 tons. The stages proposed on the Liverpool and Manchester Railway on the level part of the line were to be one mile and a half, and the loads 52 tons each. The book before mentioned was written to prove that locomotive engines were preferable to stationary engines and ropes. The latter method had been re commended by two other eminent engi neers. To put down for friction of carriages 10 lbs. per ton is very proper, although the experimentors of late, say on a new railway, it is less than nine. For gravity there is a very liberal allowance, and intended for an irregular section. I propose that the load shall first run half a mile upon a level railway, and then ascend the remainder of the two mile stage 15 feet, which would be three feet higher than the water wheel, and admit of a fall for the water to run from one stage to another, the fall of water being 12 feet. I will now proceed to calculate how much water would be required to draw the train two miles with an endless rope, the weight, including the carriages being 50 tons, to run level half a mile, and the remaining mile and a half to rise 15 feet. Gravity of 50 tons on a plane 7920 feet long and 15 feet high, 112,000 × 15÷7920 Friction of rope as before de scribed, length four miles Friction of the load 50 tons Two miles are 10,560 feet, 10,560 12 × 2240 =... Add for waste water.. Cubic feet of water.... 212 1528 500 2240 lbs. 1,971,200 985,600 6242,956,800 473,088 18,000 One lock 100 X 15 X 12 =.. 473,088÷18,000 = 26 nearly. Explanation of the foregoing :2240 lbs. is the power required to move the 50 tons, and the ropes up the plane the length of 12 feet, supposing the water to fall in a body so far. 10,56012= 880. Then 880 is the number of times that 2240 lbs. water must be applied to move the load two miles, and 2240 X 880 = 1,971,200, which is the quantity of water required to move the load two miles, except what is to be added for waste, which is a point on which men are not all agreed; but if half be added, it will probably be a little more than enough, and will be 2,956,800 lbs. 624 lbs. are one cubic foot, and 47,308 the cubic feet of water required to move COMPARATIVE EXPERIMENTS ON PROPELLERS OF DIFFERENT KINDS. the load two miles with a double rope, as proposed by Mr. Herron. This being 26 locks-full, can only be used where the quantity of water is very abundant, the supply being from a river. The time for moving the load two miles being 12 minutes, the quantity of water flowing in one minute would be 3942 cube feet, and in one second 65 7-10ths, and if the velocity of the wheel at the periphery be four feet per second, then each bucket should contain 16 4-10ths cube feet, which is far too much, and is not practicable; therefore the load of 50 tons should be reduced to 25 tons, in which case the rope need not be so strong or heavy; and a water wheel with buckets holding less than eight cube feet would answer, and the power of such a wheel would be 30 horses, ascertained thus:-First divide 1,971,200, the pounds of water before mentioned, by two, and this number by 12 minutes will produce the quantity of water to flow per minute, in order to move 25 tons up the plane; this is to be multiplied by the fall 12 feet, and divided by 33,000, gives the horse power as above stated. The foregoing is written with a view of examining and to comment on the 199 theory of James Herron, which he invites others to do. He also recommends the use of water wheels, to be placed in a canal lock, and the waggons to run upon the towing path made wide, with an ashler paving, and I have made some calculations on the subject, and find that if the water now used on the Huddersfield canal, in passing boats through locks, were to be applied to water wheels, and a railway made on the towing path, that three times the business could be done, that is now done; and as the time would be reduced to one-third of the time now required, the business upon the line would be about three times as much as it now is; as the speed also would be much quicker than that of the stage coaches, the proposed conveyance would have the preference as a conveyance for passengers. The Huddersfield canal locks are supplied by reservoirs, made on very high ground, to hold rain water running into them. They supply the summit level on an average daily with more than 7000 tons of water, which is drawn from it to pass boats laden with less than 600 tons. Manchester, Dec. 10, 1839. SENEX. COMPARATIVE EXPERIMENTS ON PROPELLERS OF DIFFERENT KINDS. BY GEORGE RENNIE, ESQ., C. E. Sir,-Having now completed the whole of the experiments on the comparative merits of different kinds of propellers for moving vessels through water. I no longer hesitate to communicate them to you. The experiments were made in three different ways. 1st. By means of a model. Dimen- Time in sions falling of a of wheel. 4lb. weight. 22 In the first case the model was placed in a trough of water, in which the surface of the water could be raised or lowered to any requisite height, and a pulley being fixed on the axle of the wheel, enabled it to revolve by the descending of a weight through a given height, so that the time of its descent became an index of the resistance. The following are the average results of the experiments : Area of floats Weight Area of Number of Floats. 16 rectangular floats. : 16 rectangular floats immersed double usual depth. 16 Ditto. Conclusions. From the foregoing experiments, it appears, 1st, that the trapezium-shaped float, having only of the breadth and of the area of the rectangular float, has an equal resistance. 2d. That when both kinds of floats are immersed to double of their ordinary immersion, the resistance of the trapezium float is only of the rectangular float. If this remarkable property of the latter, of working nearly as well under water as when plunged to the usual depth, holds good on a great scale, the difficulties experienced by steamers in the early period of their voyage, when deeply laden with coals, and when the engines can only make half their usual number of strokes, is overcome, and their voyages are likely to be considerably shortened. 2ndly. The experiments made in the different kinds of propellers on a row boat, having been made under equal circumstances, as to the magnitude, weight, and area of the boat's midship section, and with uniform magnitudes and areas of the propellers, and power to put them in motion, were as follows: Table in which are compared the Performances of the Screw-propeller, Conoidal-propeller, and Paddle-wheels, in the Grand Surrey Dock, made in the months of August and October; the Boat was worked by two men turning a winch. N.B. Dimensions of boat used in above experiments, 5 feet wide, 27 feet long, and 1 foot 10 inches in depth; weight of boat, ballast, &c., 2,828lbs. ; area of midship section of boat's immersion, 483 square inches. Conclusions.-That with reference to area, the trapezium-shaped paddle-wheel is superior to the rectangular; but that the conoidal-propeller, taken without reference to area, exceeds all the different kinds. The principal objection to the propellers working under water, arises from the great velocity which must be given to them, and the complicated machinery necessary to produce it. 3rdly. The experiments of the two kinds of paddle-floats in a steamer. The following is GILBERT'S IMPROVED GAS-STOVE. 201 Average of Experiments made on Paddle-wheels with the "Pink" Steam-boat, made at the West India Import Dock, in November last. 6.34* Conclusions.-The conclusions to be derived from the last experiment, are important. 1st. That with one-half of the area and one-third of the width, the trapezium-shaped propeller presented the same resistance as the rectangular float, while from its peculiar form the total immersed area was two-third of the immersed area of the rectangular float. 2ndly. That on account of this form it enters the water without shocks and vibrations as in the case of the common float, and leaves the water without carrying up a large portion of it like a cascade, whereby a considerable portion of the power is expended uselessly. 3rdly. That the width of the paddle 23 × 9=207 square inches; area of floats immersed, 635; extreme diameter of wheel, 7.4. Wheels fitted with trapezium-shaped 18 × 111 floats (acute angle down), 2 103.5 square inches; area of floats immersed 432.25 square inches; extreme diameter of wheel, 8.10. box, and, consequently, the resistance of the wind, one-third will be diminished. 4thly. That the lateral undulation and consequent tear and wear and danger to the engines, by the constant plunging in and out of the water, will be in a great measure obviated. 5th. That one-half the weight and present cost of paddle-wheels and boxes will be saved, while the vibratory motion, so disagreeable in most steamers, will be done away with. Trusting that the foregoing will be sufficiently explanatory, I remain, Sir, London, 12th December, 1839. GILBERT'S IMPROVED GAS STOVE. At the Bath Instruction Society last week, the Principal, Edward Osler, Esq., late of Falmouth, delivered a lecture to the Associates on the different methods of warming and ventilating buildings, in the course of which he called their attention to a gas stove, on a new and improved principle, which has just been fixed in the school-room of the City Commercial School. The common gas stove is merely a covered cylinder of iron, containing a hollow ring communicating with the gas pipe, and pierced with minute holes, from which the gas burns in small jets. The products of the combustion, mixed with a portion of gas, (for the gas is never wholly consumed when burnt in a jet) are discharged into the room, the air of which is thus rendered very unpleasant, and even unwholesome; hence the use of these stoves is confined to halls and shops where there is a very free ventilation. In the improved gas stove these evils are entirely avoided. The gas is first mixed with a sufficient proportion of atmospheric air to en sure its complete combustion and then passes through a plate of wire gause, on the surface of which it burns with a flickering blue flame. The combustion takes place within an oblong iron box, which is thus heated sufficiently to diffuse a soft and equable warmth through the apartment. A pipe carries off the vapour into the chimney. No inconvenience or risk whatever is connected with the use of the stoves, and the fire can be lighted or extinguished with the same facility as a common burner. This consideration, with the perfect freedom from dust and the avoiding of all trouble in keeping up the fire, makes the stove particularly desirable for a school-room. It also promises to afford an easy, cheap, and effectual means of warming a conservatory or hothouse; and it may be conveniently introduced into dwellings, for in addition to its use in warming the apartments, it may be employed, to a considerable extent, for cooking. The stove fixed in the Bath City School was made by the inventor, Mr. Ed *This small difference arises from a small portion of the float having been obliged to be cut off on account of an iron stay interfering. THE EARLIEST PRINTED NEWSPAPER. ward Gilbert, Civil Engineer, &c., of Fal- Society of Cornwall. Any person wishing THE EARLIEST PRINTED NEWSPAPER. * It has always been a difficult task to settle points of priority in discoveries and improvements. Take the art of printing, for instance, and it will be found that there is no absolute certainty as to the real discoverer of any new process, from the very first origin of the art down to our own days of stereotype and steaming. That the same uncertainty has also attended the productions of the press, an illustration is supplied by a pamphlet which has recently appeared, the object of which is "to demonstrate that the claims of the English to the invention of printed newspapers are unfortunately of no validity.' There are, probably, few readers of the Mechanics' Magazine who have not met with the assertion, till now uncontradicted, that, although written newspapers may have been invented by the Italians, the first printed journal was issued in our own country, pending the threatened descent of the Spanish armada, and under the superintendence of the profound and sagacious Burleigh. We are sorry to assure them that the facts brought forward in this pamphlet are amply sufficient to overthrow this theory, and to prove that the supposed genuine specimens of "The English Mercurie," preserved in the British Museum, are neither more nor less than downright forgeries. The proofs brought forward by the author (who made the discovery) are strong and clear. The printed papers, it appears, are in a type so modern, that the idea of their belonging to the time of Elizabeth is out of the question, and, singularly enough, in the archives of the Museum are also preserved certain MSS. which had evidently constituted the copy" followed by the printer, and which are very ingeniously traced as of no older date than the early part of the last century. Finally, the test of comparison with contemporary chroniclers is A Letter to Antonio Panizzi, Esq., Keeper of the Printed Books in the British Museum, on the reported Earliest Printed Newspaper, "The English Mercurie, 1588." By Thomas Watts, of the British Museum, London. Pickering, 1839. 8vo. pp. 16. ing on this score also. A vast number applied, and the "Mercurie" found want of minor corroborative proofs are introduced in the course of the investigation, all contributing to make out a clear case, and of themselves so cogent, that it is probable, even had not the irresistible MSS. come to light, Mr. Watts would have been enabled to expose the fraud almost as convincingly as he has done with its powerful assistance. Thus has perished an imposture which had met with the most extraordinary success, during the whole of the half century that had elapsed since the claim was first set up by Mr. George Chalmers, the antiquary, and which, it seems, has taken in not only our own grave encyclopædists, but those of many other countries also. For, as our author informs us, "the Conversations Lexikon of Brockhaus, and the Neuestes Conversations-Lexikon of Wigaud, mention it (the Mercurie) under the article Zeitung; the Dictionnaire de la Conversation et de la Lecture, under the head Gazetier; the great Russian Entsiklopedicheskii Leksikon, under that of Gazeta ;" while it is noticed also in the Encyclopædia Americana, published at New York, and, doubtless, in many other publications of equal calibre. "There could hardly, in fact," observes Mr. W., "be any circumstance in literary history apparently established on a firmer foundation than this. A statement originally made on respectable authority, and repeated by so many others, was supported by a reference to a document preserved, not in a private library, or in one difficult of access, but in the most public, the most easily accessible, the most universally frequented collection in the capital. Any doubt or suspicion that might arise could be confirmed or dispelled at once, by applying for the volume, which was daily within call of hundreds of literary men, both English and foreign." Under such a state of things, who could have anticipated that such a claim as the one in question would have remained unchallenged for so long a period as from 1796 to 1839? |