Sir-From the non-appearance of my letter of the 3rd inst., respecting Mr. Mills's pump, I conclude that you considered it anticipated by Mr. Baddeley's communication on the same subject in No. 778, page 231. I freely acknowledge that Mr. B. was fully entitled to the preference, as well from priority in the date of his letter, as from his known experience in the world of hydraulics. I took, however, quite different ground from him; he confining himself to objecting to the practical efficiency of the pump, while I directed my remarks to its total want of originality; in fact, all the objections adduced of Mr. Baddeley may be found in any of the many treatises wherein the pump of Haskins is described.

There is, however, one most extraordinary blunder, into which Mr. Baddeley has fallen, and which I sincerely regret, as it may afford a peg to Mr. Mills or his friends whereon to hang an apparently successful answer to his letter. It is that part wherein Mr. Baddeley says that Mr. Mills's pump is of the lifting, and not of the suction kind, as stated in Mr. Mills's description.

Now, that the contrary is the case, is an axiom so palpable to any one who has glanced at the rudiments of hydraulics, that to attempt to prove it by any serious argument is almost puerile; but, when such an authority as Mr. Baddeley is supposed to be, writes it, not as à random assertion, but as a grave accusation of want of correctness in description, a few words in proof of his egregious mistake may be excused.

A lifting pump, then, is that wherein the piston acts entirely beneath the surface of the water to be raised; for, if the piston act in the least above such surface, the pump partakes of the suction kind. Ordinary pumps, with a valve in the piston, are of this mixed nature, -the water beneath the piston being sucked, or supported by atmospheric pressure, while that above the piston is lifted.

Now, it is evident, that in the mercurial pump, decscribed at page 190, the piston being 30 feet above the surface, it is, in its up-stroke, altogether of the suction kind, and, in its down-stroke, of the force kind: the term lifting force-pump, which Mr. Baddeley has conferred on it, is, therefore, glaringly wrong; while the

STEAMING ON CANALS- ERICSSON'S PROPELLERS.

We copy from the Manchester Guardian the following account of a very successful experiment made on the Duke of Bridgewater's canal with Mr. Erics son's propellers, described in our 751st Number. The account is defective and erroneous in many particulars, and in none more so than in the ascription of all "the merit" of the affair to Messrs. Robins and Co. (the well-known carriers), and the apparently studious omission of the name of the ingenious and indefatigable inventor, Captain Ericsson. We have subjoined, therefore, some notes which may help to set the matter in its true bearings before the public.

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As our American neighbours would say, we are going a-head" in the use of steam as a locomotive power. But a few weeks ago we noticed the starting of a small steam boat to ply on the Irwell, with passengers, between this town and Warrington; and we have now to announce the application of steam to carriers' canal boats for the transit of goods between this town and London. In canal navigation in this country, a long period of time has elapsed since any alteration or improvement of any great importance has been made. The boats are of the same construction, and so inartificial is the mode of working them, that the only means in practice, at the present day, for propelling them through the immense tunnels, of which one is nearly a mile in length and another three quarters of a mile, is for the boatmen to lie on their backs on the tar paulin which covers the goods with which the boats are deeply laden, and, by pushing their feet against the roof of the tunnel, work the boats onwards at a tediously slow rate, with great labour and fatigue, amidst the smoke from the boats' chimneys or funnels, which, to any one unused to its effects in a long tunnel, would seem wholly unendurable. This is what the boatmen

term legging through ;" and in this way

every boat-load of goods is worked onwards through the tunnels on every great waterline of internal navigation in the country. The first application of steam on canals has been made, not on a new form or construc. tion of boat, nor even on an iron boat of similar form, but on one of the long narrow canal boats, with sharp stem and stern, which had for some time before been plying on the canals in the usual way. The experiment which has been tried, at little cost, and which, at best, is an imperfect one, has, however, been eminently successful; and there appears very little doubt that its results will be a revolution as complete in canal navigation as the introduction of marine steamers has worked in our coasting packets. The merit of making this experiment belongs to Messrs. Robins, Mills, and Co., carriers, of London, and of Castle Field Wharf, in this town. Into one of their canal boats, near the stern, they introduced a small high-pressure marine steamengine, of only four horses' power, to which a boiler that had been used for one of the locomotive engines on the Liverpool and Manchester Railway was adapted (1.) As the narrowness of canal tunnels and the injury likely to result to the banks from the use of side paddles must always have thrown a difficulty in the way of applying steam power, in the ordinary mode, to canal navigation, it became necessary to substitute some paddle which should not be in the way, while it should not be liable to the objection of injuring the banks. This difficulty has been surmounted, as it seems to us, very satisfactorily and completely, by an ingenious application of the principle of the old fish-tail paddles (2.) These paddles are placed at the extreme stern of the boat, and this terminating in a sharp point, it was necessary to lengthen the boat, and make a square box to contain the paddles (3.) They consist of two small wheels, placed side by side, not working parallel to

(1) The boiler is not one that has been used for locomotive engines-it is one invented by Captain Ericsson, and of quite a peculiar construction. It is besides only 5 feet 10 inches long, while locomotive boilers are never less than 12 feet. The cylinder is 12 inches in diameter, with a 10-inch stroke, making about 70 strokes per minute; the steam always kept at 30 lbs. per square inch. The scientific reader will allow that such power is good measure for "four horses."

(2) The propeller is by no means on the principle of the "old fish-tail paddles." See description in Mechanics' Magazine, No. 751. The Guardian's process of reasoning seems to be this; the tail of a fish is (commonly) behind the rest of its body, Captain Ericsson's propeller is placed behind; ergo Captain Ericsson's propeller and a fish's tail are very much alike. By the same sort of logic it might with great ease be shown to be very like the famouos pigtail at Charing Cross.

(3) The boat has not been lengthened, A square

the boat, but transversely, and revolving contrary ways (4.) The paddle-boards or plates of iron, of which there are six on each wheel, have an inclination of about 45°. When in action, therefore, it will be seen that, as one wheel of paddles strikes the water on the starboard side of the stern, the other strikes it on the larboard, thus producing an action on the water resembling that which sailors call the double scull," and which is the best effort of art that we have seen in imitation of the mechanical action of the tail of a fish when swimming (5.) The defects of the present experimental engine, &c. seem to be rather in its adaptation and arrangement than in itself. In the first place, we should think a more powerful engine necessary to the fair development of the power of steam in this species of navigation, considering the great length of the boat and the bulk and weight of its cargo, which is probably eleven or 12 tons (6.) Then we have no doubt, that that form of boat which has hitherto sufficed for the slow dragging of horses and a towing line, is not precisely the shape and build, nor, perhaps, is timber the best material for canal steam navigation. Again, it appears to us that the engine was rather too far from the paddles to exercise its full available motive power (7.) But these and several other points, into which we have not time to enter, will, doubtless, receive a full and sagacious consideration from scientific and practical men when once their attention is directed to the subject (8.) That the time for this, we think, bearing in mind the power and force of competition in every branch of trade and mode of communi cation, cannot be far distant. But to return to the Novelty, which is the new name the

piece of wood has been attached to the stern part, but which does not project more than 10 inches further aft than the point of the stern of the ordinary flyboats.

(4) The paddles are not placed "side by side." See above Number of Mechanics' Magazine.

(5) The paddles do not "strike the water;" the propulsion being perfectly uniform, a gradual sliding of the water takes place from the stern.

(6) The engine is by no means a defective one, nor has it been found not powerful enough; on the contrary, its power is full 20 per cent. too great for the paddles, which ought, in point of fact, to have been much larger.

(7) The power of the engine is communicated to the paddles by means of a straight shaft of about 12 feet in length. Does the Guardian suppose that if this was reduced to 6 feet the power of the engine would be increased?

(8) The inventor, Captain Ericsson, being neither scientific nor practical!-and all "the merit" in the case consisting in the introduction by Robins and Co. of the "old fish-tail paddles!" if our cotemporary will but condescend to advise with some of the many "sagacious, scientific, and practical men" to be found in his own neighbourhood, he will be surprised to find how little he really knows about the whole matter.

boat received when from a [tow] liner she became a steamer, the first voyage she made very recently from London to this place with very considerable success. Like her great prototypes, the Great Western and the Sirius, a log was kept of her rate of steaming during this her first outward voyage; but we have not been able to obtain a sight of this log, and can, therefore, only very generally notice her performance, which, we understand, was at the rate of nearly eight miles per hour. She left Pad

dington on Thursday week, at noon, with about eleven tons of goods, but was detained for several days on the Grand Junction canal, waiting her turn to proceed: notwithstanding this delay, she reached here about half-past three o'clock on Wednesday afternoon last, without having sustained the least injury, except that, having been lengthened, she was a little too long conveniently to pass some of the locks; and the result was, that her paddle-boards were a little bent and put out of order. They were speedily put to rights; and, on Monday last the proprietors, with a party of friends, proceeded with the boat on an excursion down the canal, we believe as far as Runcorn, when her speed was tried, with the favourable results already noticed. On Monday evening she took on board a cargo of bale or pack goods for London, and, we believe, started on her homeward voyage the same night. We understand that when going at the rate of eight miles an hour she does not occasion the least swell. It is anticipated that she will be able to deliver goods in London in three days from her departure from this place. On one occasion shortly before her first canal voyage, the Novelty towed the city barge, on board of which were a hundred and fifty gentlemen, up the Thames as far as Teddington Lock, at the rate of about eight miles an hour; and her performance then gave the highest satisfaction to all who witnessed it.

Since penning the preceding notes, we have seen a subsequent notice in the Guardian, which we also insert, in which we are glad to observe tardy justice is done to Captain Ericsson, and the character of the improvement is a little more correctly appreciated. It is not a little amusing, however, to note the pertinacity with which our contemporary sticks to his fish tail resemblance, while in the same breath he does his best to show that there is no resemblance at all. (Second notice in the Manchester Guardian.)

In an article under this head in the Guardian of Saturday last, we noticed the

first down voyage to this town from London, through the canals, of a steam-boat named the Novelty.

We have already stated that the Novelty is the hull of an old canal boat. Her form, to those unacquainted with the build of these boats, will be better understood when we state that her length is about 74 feet, with a seven feet six inch beam; she is heavily constructed, and when loaded draws about two feet water. We noticed that her engine was high pressure, and of four-horse power, supplied with steam from a small locomotive boiler. The boat is fitted with a species of paddles, already described, but perhaps better known as "Ericsson's" propellers, in substitution of the side paddles of the old steamers, which are constructed so as to propel without raising a surge injurious to canal banks, and so as to pass through the narrow locks with ease and safety objects hitherto unattained, and deemed impracticable. The main peculiarity of this invention is the construction of the paddle, so as to secure an action resembling that of a fish's tail, or of a perpetual sculling through the water. The difference between the operation of these propellers and that of the fish or double scull is, that instead of the force being alternate from side to side, the propellers' strokes upon the water are simultaneous. As these propellers work with the greatest effect when submerged, no waste of power is incurred, and no shaking motion communicated to the boat. When in motion, with her propellers submerged, there is little to distinguish the Novelty from other canal boats, the old wooden funnel being retained; there being little smoke, as coke is the fuel consumed: the engine and boiler being out of sight, and the only variation in her form being the elongation and widening of the stern, about 14 inches, with the addition of a slight stage for the helms

man.

We noticed the fact of an experimental trip having been made by this boat on Monday week upon the Duke of Bridgewater's canal. The party on board consisted of some of the principal canal proprietors and water carriers in this town and neighbourhood, and their friends. The Novelty

started from the Manchester end of the canal about six minutes before one o'clock; passed the Worsley branch at twenty minutes past one o'clock, and reached the wharf at Altrincham at half-past two o'clock, having performed the eight miles in one hour and 36 minutes. The speed of the boat, and the fact of no towing horses being visible, caused no small astonishment to various rustics on the canal banks, and some of the more cunning of these people, hear

66

ing the panting of the engine, and seeing the bubbling of the water in her wake, at length decided that there was summut aloive in her tail." At twenty minutes before five o'clock the boat started on her return from Altrincham bridge, and on her way came up with the Wellington fly-boat, which, having just been freshly horsed, kept a-head for about two miles, but was then obliged to yield with a bad grace, the horses being half killed under the unwonted exertion. The Novelty passed "his grace" in fine style, and arrived at Messrs. Robins, Mills, and Co.'s wharf at ten minutes after six o'clock.

Owing to the construction and form of the boat, the propellers being only partially immersed, to the engine being out of repair, and to the utter disregard of her "trim' during the experiment, it was observed that the propellers had not a fair chance; nor could the boat attain that higher rate of speed which her due emergence from the water must have produced. During the trial trip no injurious ripple was produced by the propellers; but where the water was shallow a ripple, caused by the displacement of water by the boat, followed midway, and considerably impeded her progress. With deeper water her speed accelerated, and on the Thames she is said to have attained a rate varying from eight to nine, and even up to and exceeding ten miles per hour.

We understand that the American government, ever on the alert, has availed itself of this invention. An iron steamboat, built by Mr. John Laird, of North Birkenhead (under the inspection of Mr. F. B. Ogden, the United States consul at Liverpool), and fitted with these propellers, was launched on the 7th instant. She is at present waiting for her boilers, and it is expected will be tried on the Mersey in the course of next week. She is intended to be worked as a steam tug to tow ships upon the Delaware and Raritan Canal (New Jersey), which is forty-four miles in length.

LIST OF ENGLISH PATENTS GRANTED BETWEEN THE 26th or JUNE, AND THE 26th OF JULY, 1838.

Nathan Defries, of Paddington-street, engineer, for improvements in gas meters. June 27; six months to specify.

John Perry, of Leicester, Woolcomber, for certain Improvements in combs for combing wool. June 27; six months.

Charles Green, of Birmingham, gold plater, for improvements in the manufacture of brass and copper tubing. June 27; six months.

Daniel Beckham, of No. 22, Sussex-place, OldKent-road, Surrey, stereotype founder, for an improved mode of obtaining castings in gold, silver, and albata. June 27; six months.

James Robinson, of Huddersfield, merchant, for an improved method of producing, by dying, various figures or objects of various colours in woollen, worsted, cotton, silk, and other cloths. June 27; six months.

Edward White Benson, of Birmingham, chemist, for certain improvements in the manufacture of carbonate of lead. June 27; six months.

Richard Badnall, of Cotton Hall, Stafford, gent., for a certain improvement in the manufacture of carpets, and other similar woven fabrics, which improvement is effected by the introduction of a certain article of commerce not hitherto so employed or used in such manufactures. June 27; six months,

George Round, of Birmingham, lock filer; and Samuel Whitford, of the same place, die sinker, for a new and improved method of manufacturing certain of the parts of gun and pistol locks. June 30; six months.

Henry Grey Dyar, of Cavendish-square, gent., and John Hemming, of Edward-street, Cavendishsquare, gent., Middlesex, for improvements in the manufacture of carbonate of soda. June 30; six months.

Augustus William Johnson, of Upper Stamford. street, Lambeth, for certain improvements for preventing the incrustation of steam boilers or generators, or evaporating vessels. June 30; six months.

Matthew Uzielli, of Fenchurch-street, London, merchant, for improvements in locks or fastenings, being a communication from a foreigner residing abroad. June 30; six months.

William Dobbs, of the Penn-road, Wolverhamp ton, brass founder, for certain improvements in the construction of racks and pulleys for window blinds and other useful purposes. June 30; six months.

George Carter, of Lombard-street, London, gent., for improvements in saw mills. July 2; six months. Joseph Needham Taylor, of Red Lion-square, Bloomsbury, captain R.N., for a certain method, or certain methods of abating or lessening the mischiefs arising from the shock or force of the waves of the ocean, lakes, or rivers, and of reducing them to the comparatively harmless state known by the term "broken water," and thereby preventing the injury done to, and increasing the durability of break-waters, mole heads, piers, fortifications, lights, houses, docks, wharfs, landing-places, embankments, bridges, or ponton bridges; and also of adding to the security and defence of harbours, roadsteads, anchorages, and other places exposed to the violent action of the waves. July 2; six

months.

Edward Davy, of Fleet-street, London, chemist, for improvements in apparatus for making telegraphic communications or signals, by means of electric currents, parts of such apparatus being applicable to obtaining, regulating, or measuring electric currents for other purposes. July 2; six months.

Frederick Joseph Burnett, of St. Mary-at-Hill, London, ship insurance agent, and Hippolyte Francois, Marquis de Bouffet Montauban, colonel of cavalry, now residing in Sloane-street, Chelsea, Middlesex, for certain improvements in the manufacture of soap. July 4; six months.

Henry Elkington, of Northfield, Worcester, gent., for certain improvements in engines to be worked by steam, air, or other fluids. July 6; six months. Cornelian Alfred Jaquin, of Huggin-lane, Woodstreet, London, for improvements in the manufacture of buttons. July 7; six months.

William Knight, of Chichester, ironmonger, for improvements in machinery for raising and forcing. water and other fluids. July 7; six months.

George Salter, of West Bromwich, manufacturer, for improvements in apparatus for weighing. July 9; six months.

Claude Schroth, of Leicester-square, gent., for an improved method or methods of making or manufacturing the tools or apparatus employed in the process of pressing, or embossing the surface of leather or other substances; being a communication from a foreigner residing abroad. July 9; six months.

William Palmer, of Sutton-street, Clerkenwell, manufacturer, for improvements in lamps. July 10; six months.

William Barnet, of Brighton, ironfounder, for certain improvements in the manufacture of iron.— July 10; six months.

John Thomas Betts, of Smithfield-bars, rectifier, for improvements in process of preparing spirituous liquors in the making of brandy. July 10; six months.

Louis Cyprien Callet, late of New York, but now residing in Manchester, for certain improvements in machinery, or apparatus for producing motive power applicable to propelling boats and other vessels, carriages, machines, and other useful purposes, being a communication from a foreigner residing abroad. July 11; six months.

Henry Van Wart, of Birmingham, merchant, and Samuel Aspinwall Goddard, of the same place, merchant, for certain improvements in machinery, or apparatus applicable to locomotion on rail roads, and to steam navigation, parts of which improvements are also applicable to land or stationary engines. July 11; six months.

John Bethell, of Mecklenburgh-square, gent., for improvements in rendering wood, cork, leather, woven and fetted fabrics, ropes and cordage, stone and plasters, or compositions, either more durable, less pervious to water, or less inflammable, as may be required for various useful purposes. July 11; six months.

Job Cutler, of Lady Poole-lane, Sparkbrook, Birmingham, and Thomas Gregory Hancock, mechanist, of Prince's-street, Birmingham, for an improved method of condensing the steam in steamengines, and supplying their boilers with water thereby formed. July 12; six months.

Joseph Bennett, of Tumley, near Glossop, Derby, cotton-spinner, for certain improvements in machinery for carding wool, cotton, flax, and other fibrous substances, which are, or may be carded, part of which improvements are also applicable to machinery for drawing, doubling, and roving, and spinning such fibrous substances as are, or may be subjected to those operations. July 12; six months.

James Milne, of Edinburgh, gas meter manufacturer, for improvements in apparatus employed in transmitting gas for the purpose of light and heat. July 13; six months.

Alexander Cochrane, of Arundel-street, Strand, Middlesex, gentleman, for improvements in umbrellas and parasols. July 13; six months.

Thomas Robert Sewell, of Carrington, Nottingham, lace manufacturer, for improvements in manufacturing white lead. July 14; six months.

Richard March Hoe, late of New York, but now of 66, Chancery-lane, civil engineer, for a new or improved instrument or apparatus for ascertaining or determining the latitude and longitude of any place, or the situation of ships or other vessels at sea, and the dip and variation of the magnetic needle, which new or improved instrument he intends to denominate "Sherwood's Magnetic Geometer," being a communication from a foreigner re siding abroad. July 18; six months.

Henry Ross, of Leicester, worsted manufacturer, for improvements in machinery for combing and drawing wool and certain descriptions of hair. July 18; six months.

Henry Bridge Cowell, of Lower-street, Islington, ironmonger, for an improved apparatus answering the purpose of a press, for retaining and keeping leaves or pieces of paper, or of cloth or of other thin substances folded or unfolded in a flattened condition, under gentle pressure. July 18; six months.

John Robertson, of Great Charlotte-street, Buckingham-gate, for improvements of architecture in its forms and combinations, and also in the superficial figures which may be employed; also for an improvement or improvements in the surfaces of buildings. July 18; six months.

Richard Treffry, of Manchester, chemist, for certain improvements in the method of preserving cer tain animal and vegetable substances from decay, and also in the apparatus for and mode of impregnating substances to be preserved. July 23; six months.

George Richards Elkington, and Oglethorpe Wakelin Barratt, of Birmingham, manufacturers, for improvements in coating and colouring certain metals. July 24; six months.

Joseph Price, of Gateshead, Durham, flint glass manufacturer, for certain improvements in con structing and adapting boilers for marine, stationary, and locomotive engines, and in adapting and applying boilers to steam-vessels. July 26; six

months.

Charles Wye Williams, of Liverpool, gentleman, for certain improvements in the means of preparing the vegetable material of peat, moss, or bog, so as to render it applicable to several useful purposes, and particularly for fuel. July 26; six months.

John Gray, of Liverpool, engineer, for certain improvements in steam-engines and apparatus connected therewith, which improvements are particularly applicable to marine engines for propelling boats or vessels, and part or parts of which improvements are also applicable to locomotive or stationary steam-engines and other purposes. July 26; six months.

William Madeley, of Manchester, machinist, for certain additions to, and improvements in, ma chinery used for spinning and forming into cops upon spindles, cotton, and other fibrous materials of the like nature. July 26; six months.

Sir William Burnett, knight, of Somerset House, for improvements in preserving wood and other vegetable matters from decay. July 26; six months.

Alexander Croll, of Greenwich, manufacturing chemist, for improvements in the manufacture of gas for the purpose of affording light. July 26; six months.

Frederic Edouard Fraissinet, of Covent Gardensquare, Westminster, for certain improvements in the machinery for propelling vessels by steam, by which their speed will be much accelerated with a diminished power and with a diminished action in the water, being a communication from a foreigner residing abroad. July 26; six months,

LIST OF SCOTCH PATENTS GRANTED BE WEEN THE 22nd OF JUNE, AND THE 22nd OF JULY, 1838.

Joshua Taylor Beale, of No, 11, Church Lane, Whitechapel, Middlesex, engineer, for certain im provements in, and additions to his former invention known by the title of "A Lamp applicable to the burning of substances not hitherto usually burned in such vessels or apparatus." Sealed the 26th of June, 1838; four months to specify.

Edward Cobbold, of Long Melford, Suffolk, clerk, master of arts, for certain improvements in the manufacture of gas for affording light and heat, and in the application of certain products thereof to useful purposes. June 27.

Stephen Geary, of Hamilton-place, New-road, Middlesex, architect, for improvements in the preparation of fuel. June 27,

William Gossage, of Stoke Prior, Worcester, manufacturing chemist, for certain improvements in manufacturing sulphuric acid. June 29.

Francis Thorp, of Knaresborough, York, flax spinner, for certain improvements in machinery or apparatus for heckling, preparing, or dressing hemp, flax, and other such like fibrous materials. June 29.