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steam carriage company, I felt anxious to and putrid. The investigating party conobtain any employment. I knew that I could sisted of the celebrated physician Cotugno, do good service at Woolwich ; but how to Bruno di Amantea, Angelo della Leonessa, obtain any patronage or introduction ? So Sementini, the Prince Colonna, the Duke I wrote to Lord Hill, offering to render all of Cassano Serra, and my co-pupil Don the shoes and boots of the army, or any Michelino Serra. A portion of the foetid part of it, waterproof, and thrice as durable, water was put into the charcoal filter of at twopence a pair. I also proposed to Dall' Armi, and, after it had passed through render any portion of the parade behind it, the entire party sipped it from a goblet, the Horse Guards, whereon the troops tramp in which it was as clear as crystal, and equal in the wet in rainy weather, as dry and hard in taste to the best spring water, barring the as a marble pavement, at twopence a yard flatness which generally belongs to filtered square, by merely pouring over it, when water, from the deprivation of the air it dry, hot coal tar, as I had done to the gar previously held in solution. den walks of Mr. J. R. Bell, at Blackheath, Lightning conductors have recently been in 1816, and which endure to this day,—the brought into notice because of the injury prototype of all bituminous roads.

to St. Martin's church steeple, and the Hill presents his compliments to Colonel ignition of two ships by the electric fluid, Macerone, but cannot give him any employ On this subject I really do not know what ment!” Here you see, Mr. Baddeley, was to say. If people have not listened to the a stopper to my waterproofing proposal, and demonstrations and warnings of the great to my twenty-seven years old bituminous Benjamin Franklin, how can I expect that surface. A Frenchman named Polonceau my feeble voice, repeated and re-echoed as immediately obtained a contract to treat the it may be, will ever be heeded? But, as paths along Whitehall and Parliament-street “facts are stubborn things," I will mention with the same bituminous application, at ten one or two for the consideration of your times the price which I had proposed to intellectual readers. When I happened to Lord Hill,

be at Rome in 1811, I found that St. Peter's Now I have my pen in my hand, a word Church, isolated in a vast plain, was very on the filtration of water, which subject has frequently struck by lightning, during the lately been much mooted in the Mechanics' thunder storms which are so frequent there Magazine, and other periodicals. I do not in November and December. I was acunderstand, from all that I have read, that quainted with General Miolis, the imperial any filtration is thought of, but that of free governor of Rome, with the Count Norvince ing the water from all impurities which are de Monbreton, minister of police; M. For. mechanically suspended in it; such as is bin Janson, inspector of the museums, &c., well performed by sandstone filters called and induced them to form themselves into dripstones.Now it is of the utmost a committee of investigation. I had seen Impcrtance that the benevolent men who how the copper ball bad been riddled by the advocate the filtration of our filthy, putrid lightning, and several great stone steps disThames water, should seriously bear in located and cast abroad. The process of mind, that mere mechanical filtration and these electrical actions induced the French chemical filtration are very different things. authorities of Rome to place conductors all Any salt, or other substance perfectly solu over the church; one fifteen feet above the ble in water-for example, salt or white cross, with a point of pnre gold, and others sugar-will pass through the dripstone filter at every angle of the edifice. They were as well as the purest water. But not so all above an inch in diameter, and supported with the chemical filter, of which I will give by perforated pieces of marble let into the an instance.

walls. It is a great increase of efficacy in My friend Giovanni Dall' Armi, who in lightning conductors for them to bave their : troduced into Italy and France the art of summits terminate in many points instead lithography, in 1806 or 1807, constructed,

of one.

Such will generally draw off the in 1808, a chemical filter, composed of a electric fluid quite silently, without any dis. cask with a perforated diaphragm, over which charge or perceptible corruscation. If a was laid a thick stratum of pounded charcoal, branch of heath, broom, or a common birch and over that a layer of sand; then broken broom, be approximated to the most power. bricks, then a large sponge, or thick hair ful and fully charged electric machine, all cloth. On the 27th of September, 1813, I the electric fuid will be drawn off quite attended an experiment made at the hos imperceptibly. Thus it is that the cypress, pital called " Degli Incurabili,at Naples. the laurel, and some other trees, have been In this place there were several stone cisterns deemed " sacred," and lightning-proof, by to macerate skeletons, so as to clean the the ancients, because their innumerable sharp bones. Each cistern contained two or three pointed leaves prevent any electric disskeletons, and the water bad become brown charge. Electricity is the main supportes

was

of vegetable life ; in some cases, I am convinced that it is the only one ; whereas, in some of the lower orders, such as the Para. siti and the Fungi, it seems to be less needed. In the “lower orders" I do not include the Grammine, which, I could show, are highly affected by the electrical state of the atmosphere. But this disquisition is not to my present purpose, and would lead me to a great length of disquisition, which I shall detail in my continuation (if I live) of the “Electrical Theory of the Universe," three papers on which appeared long ago in your omni. important miscellany. I have the honour to be, Sir, Your obedient servant,

F. MACERONE. P.S. Tubes form better conductors than solid bars, because they have two surfaces. The conductors in this country are not onetenth of the proper size. should have chains proceeding down the shrouds into the water.

TUE INVENTION OF STEAM DREDGING,

AND THB LATE RICHARD TREVE-
THICK,

Sir, -As considerable doubt still hangs over the first application of steam to dredging purposes, I send you a few particulars which will throw some light upon the share which the celebrated Richard Trevethick had in this work. These particulars, it must be admitted, are not so satisfactory as could be wished; but, considering the obscurity which is thrown round the origin of this invention by all the writers in the Encyclopædias and other standard works, any contribution to the very scanty information which is already published on the subject will, I think, be interesting to your read

The particulars I have to furnish are contained in the following extracts from a letter written by Mr. Edward Biggs, of Igtham, in Kent, who was for many years the principal manager of the extensive dredging operations carried on by the late John Hughes, in the river Thames, for the Corporation of the Trinity House, the East and West India Dock Companies, and other public bodies. I am your obedient servant,

AN ENQUIRER. Extract from Mr. Bigg's Letter. “ In the year 1806, I erected a steam engine on board the ballast lighter Brunswick, burden 60 tons, for Messrs. Hughes, Bough, and Mills, which was employed to decpen the river Thames, at the East India Moor.

ings, Blackwall; and in the early part of 1807, my late friend, Mr. Richard Trevethick, came on board and looked at the machine, and afterwards engaged by Messrs. Hughes to erect a dredging engine on board the Blazer gun-brig, a vessel about five-times the burden of the Brunswick. When it was finished, or, as it was then thought to be, Mr. Hughes, the late Mr. D. Vaux, engineer of the City Canal, and Mr. Mills, came to me on board the Brunswick, at the East India moorings, and informed me that the Blazer dredging engine was defective in some parts of its machinery, as it could not perform the work it was intended to do. They then wished me to go on board the Blazer and examine it, but I strongly objected, saying, I did not like to interfere with any other person's business; Mr Hughes then said that if I would not go on board to see what was wrong, the vessel must be put into Perry and Wells' dock, as it was a great expense to keep her on the river with two sets of men, when she was scarcely doing any work. Mr. Hughes then showed me a calculation of the expense of the Blazer dredging engine, and pressed me very much to go on board and make the necessary alterations, and I then complied with his request. The Blazer was after that time employed in finishing Mr. Hughes' work at the East India moorings, and afterwards for raising gravel near Westminster Bridge, at the entrance to the docks, and at various other places in the river.

“ Mr. Trevethick was also engaged by Messrs. Hughes at the same time, to erect a dredging machine on board the Plymouth bomb brig, lying at Limehouse Hole; but when they found the Blazer engine defective, they requested me to go on board the Plymouth, and make a report to them on the subject, which I did ; and then the boiler, engine, framing, &c., were taken out of the vessel immediately. Messrs. Hunter and English, of Bow, were then employed to erect a dredging machine on board the Plymouth, which vessel was first set to work to good effect, at Woolwich Dockyard.

“ If my late friend Mr. Richard Trevethick, were now alive, he would, I know, assent to every word I have written on this subject. For several years before Mr. Trevethick left England to go to South America, we were very friendly indeed; he frequently coming to the works where I was engaged, and whenever I could spare time I used to spend a day very pleasantly with him in London; he pressed me very much to go with him to South America.

“ Mr. Trevethick was a very ready clever mechanic; he died a few years ago at Dartford, in Kent, 13 miles from this place.

“ The late Mr. Rennie, and the late James

ers.

Watt, came on board the Brunswick in other sources than myself, I will thank him 1807, and they afterwards built a dredging

to do so. If he cannot, why then, as a neengine for the fens in Lincolnshire."

cessary consequence, I being a stranger to Mr. M., must have made the subject public before it could have come to his knowledge.

There is another point I shall just notice. MR. DREDGE'S SYSTEM OF BUILDING sus.

The note, runs thus:--
PENSION BRIDGES.

“ This yariation of the section of the chains Sir,-I am particularly obliged to you is exhibited in a suspension bridge recently for the able vindication of my claims in your invented by Mr. Dredge, and appears to notice last week of Professor Moseley's constitute the whole merit of his intention." “Mechanical Principles of Engineering and The careful reader will at once perceive Architecture," the more so, as but for that, that Professor Moseley here allows my in. I might not have known there had been any vention to be all he before demonstrates to occasion for it, not having seen the work it. be so beautiful and essential in suspension self. Your remarks may probably seem to bridges; but he will also see that he does it render any thing from me unnecessary; yet, with a bad grace, wishing to conceal the nevertheless, I will venture to say a few merit of the inventor as much as possible words, for which, perhaps, you will allow a from the observation of his readers. I will space in your Journal. As I am still without

not attempt, for I cannot divine his reason the advantage of having seen the Professor's for such conduct, unless it is to arrogate to work, all my present information must be himself, by borrowing and building on other considered derived from your review.

men's ideas, a merit that is not his own. From this, it appears that Mr. Moseley But of this meanness, without sufficient “has demonstrated that it is false in principle cause, I would not willingly accuse any man, to have a uniform section of iron for the nor will I Mr. Moseley until I have seen his chains of a suspension bridge, and that if it work. is required to build a bridge of uniform Before I conclude, I beg to inform Mr. strength, and therefore, with the greatest Moseley, however, that the, tapering the economy of material, the area of the section

suspension chains is not the only merit I of the chains should increase from the lowest claim for my invention. So far from that point towards the main points of suspension.” being the case, a variation in the sectioa of It also appears, that the Professor is very the chains is merely a consequence of that particular in pointing out in his Preface, part in which the chief merit lies. What I that this beautifully simple principle is in allude to is the arranging of the suspending troduced for the first time.

rods, which I place in an oblique instead of As far as his demonstration of the fallacy a vertical direction, with respect to the horiof the old principle of suspension goes,

I

This it is which has all along bothered thank him for the trouble he has taken ; be so many of the mathematicians and engineers, cause, just so far as his formulæ are correct, and this it is alone which allows me to taper just so much is he assisting me in establish the chains of a suspension bridge to the ing my views on the subject. But, he may extent I propose, and have carried out so rest assured, he will find very few, if any repeatedly in practice. If Mr. Moseley has persons ready to give him that credit he so

not taken the effect of these rods into his anxiously seeks, for introducing a principle calculations, I fear I shall not receive that which was mooted and made public before assistance from the Professor's labours I at his book was written, or indeed “thought

first calculated upon. of;" for, notwithstanding the Professor's Let me request of Mr. Moseley to come assertion in his Preface, I deny that he has forward and establish the position he has the slightest claim to any merit for that taken in his work, and, by so doing, diswhich I alone invented and introduced. I

prove mine ; and I hope he will have a do not suppose that Mr. Moseley wishes his sufficient regard for his reputation as a man readers to think him the inventor of the prin of science to clear it from all appearance of ciple he describes : I therefore request, and the stigma which the borrowing of another's in common fairness have a right to expect, ideas, without a suficient acknowledgment, that he will state whether or not he has ever would infallibly cast upon it. seen this principle of suspension carried out

I am, your obedient humble servant, in practice, or any description of it, but such as has come either directly or indirectly

J. DREDGE. from me? Or whether he thinks the vary [We regret the warmth with which Mr. ing section of the chains, and the use of the Dredge expresses himself; but, at the same oblique rods, were ever thought of until I time, we cannot but feel that it has its crput them in practice across the Avon, at cuse. Professor Moseley will no doubt do Bath ? If he can trace bis inforination to what is right in the matter.-ED, M. M.]

zon.

APPLICATION OF WIRE-ROPE AS A LIGHT

NING CONDUCTOR-MR. ROBERTS IN
REPLY TO MR. HILL.

Sir,- In gentlemanly society it is not tolerated for one individual to say to another,

Sir, I charge you with stating a falsehood; I know there may be proofs you are correct in your statement, but it suits my purpose to maintain that what you assert is not true, and I will therefore not take the trouble to search for proofs of your correctness, and my misstatements." This, in effect, is Mr. Hill's letter of the 12th. What the practice may be amongst his intimates I know not, and have no wish to know.

Your readers will find in the Report of the Committee on Lightning Conductors, which sat in 1839, sufficient proofs that I am known to the Lords Commissioners of the Admiralty, and that the plan now claimed by Mr. Hill, for Mr. Smith, is indisputably mine.

I am fortunately too much occupied with matters of importance to lose time in further discussion with Mr. Hill.

Yours, &c.,

MARtyn Roberts. [We have referred to the Parliamentary Report on Lightning Conductors, mentioned by Mr. Roberts, and see in it sufficient to induce us to regret extremely that our columns should have been made the me. dium of the depreciatory observations of which he very justly complains. It is established by the documentary evidence attached to that report, that Mr. Roberts proposed the application of wire rope as a lightning conductor, in a paper read before the Electrical Society, on the 24th of June, 1837 --that he brought this plan most pointedly under the attention of the Admiralty in May, 1839—and that, when a royal commission was subsequently nominated to enquire into the subject, he was applied to by them for his advice upon it, and gave it frankly and unreservedly. Of Mr. Smith, all this while, we see no trace. The truth is, that Mr. Smith's merit consists solely in latterly supplying, as a manufacturer, the wire rope which Mr. Roberts first suggested should be applied to the purposes of electrical conduction; and as there seems now every appearance that wire rope conductors will be those universally preferred, we trust Mr. Roberts will not go without his reward.—ED, M. M.]

this vessel, alluded to in our brief notice of the 10th instant.

The experiments were made on the 16th, 17th, and 18th of November. The vessel left Woolwich about 10 o'clock A.m. on the 16th, and in about half an hour afterwards passed the Rhadamanthus, which had left Woolwich at 9 o'clock. At about half-past 11 o'clock she stopped for a few minutes at Gravesend, and then proceeded, with a strong breeze ahead and adverse tide, and at a quarter-past 1 o'clock passed the Nore-light vessel ; arrived at Ramsgate 25 minutes past 4 o'clock, when the weather was so severe that none of the London steam-vessels arrived during the course of the day. The weather continued so boisterous on the 17th that the Widgeon steam-vessel was under the necessity of putting into Ramsgate harbour at an early hour for shelter. The Ma. gician, however, left Ramsgate shortly after 11 o'clock A.M., the wind blowing at the time a strong breeze from the eastward, and at 53 minutes past 12 o'clock passed Dover Pier, with a very heavy sea running. At 24 minutes past 1 o'clock, when opposite Folkstone, she put back for Ramsgate, where she arrived at 44 minutes past 3 o'clock.

On the 18th the Magician left Ramsgate at 17 minutes past 10 o'clock A.M., with flood tide, and at 14 minutes past 3 o'clock P.M. arrived off Woolwich.

The average speed of the engines from Ramsgate to Woolwich was 354 revolutions per minute, length of stroke 3 feet 6 inches, height of steam gauge 7 inches, height of barometer 287 inches. The boilers are constructed on the tubular principle, very small, and generate steam well. The consumption of coal was about 6 lbs. per horse power per hour, and the vessel was found to be extremely easy and dry in a heavy sea. The average speed of the vessel from Ramsgate to Woolwich, the distance being estimated at 85 miles, in five hours, was equal to 14 knots, or seventeen statute miles, per hour !!!

We must not forget to add, that the Magician is fitted with a condensing apparatus on the plan of Mr. Howard.

ABSTRACTS OF SPECIFICATIONS OF ENGLISH

PATENTS RECENTLY ENROLLED. JOHN JAMES BAGGALY, OF SHEFFIELD, SEAL-ENGRAVER, for certain improvements in making metallic dies and plates for stamping, pressing, and embossing. Patent dated January 22, 1842.

A mould of the design to be embossed is first to be obtained in bas-relief, from which a sulphur cast in alto relievo is to be taken. A reverse mould, called a “hub, or sinker,"

THE “MAGICIAN" STEAMER. We have been favoured with the following details of the experiments made with

is then taken from the sulphur cast, of about into an iron vessel, to which heat is apthe thickness of an eighth of an inch, which plied, and well stirred until all the ingre. forms the matrix of the die required. A dients have become thoroughly amalgamated; steel plate is next made red-hot, on which it is then drawn off, by means of a tap, on the hub or sinker is placed, and, by repeated to slabs, and allowed to cool, after which it blows, the steel is pressed into all parts of is cut into pieces, ready for use. When a the matrix ; so that, on cooling, the steel less elastic glue is required, it is composed plate exhibits a correct fac-simile, in relief, of 1 part of naphtha and 2 parts of gum or of the required design. The die thus pro shellac. Previous to using, the glue must duced requires to be cleaned off, technically be heated in an iron pot to 250° Fahr., care called “ got up," and is then soldered to a being taken that the surfaces about to be bed of cast-iron. Instead of a steel plate, joined are perfectly dry. annealed malleable iron may be used.

The claim is to the use or application, in The claims are, 1. To the producing from preparing masts, spars, and other wood for flat plates of steel, or other metals, the subject ship-building and other purposes, of a glue of a required die by the means above described. insoluble in water, and more elastic than the

2. To casting the said subjects from a glue in ordinary use. matrix, and afterwards treating such metals MARC CARLOTTI, OF LITTLE ARGYLE. as above described.

STREET, REGENT-STREET, GENTLEMAX, for 3. To the attaching such stamped dies to certain improvements in the construction cast-iron blocks by means of solder.

and manufacture of boots, half-boots, shoes, RICHARD BEARD, OF EARL-STREET, clogs, and goloshes. Patent dated April 8, BLACKFRIARS, GENTLEMAN, for improve 1842. ments in the means of obtaining likenesses Wooden soles are introduced between the and representations of nature, and of other outer sole and lining of the boot, which are objects. Patent dated March 10, 1842. calculated to protect the feet from wet, and

Mr. Beard's improvements consist in co to effect a saving in the wear and tear. louring the pictures obtained by the Da The improvements in clogs and golosbes guerreotype process. After a picture has consist in substituting springs for the anclebeen obtained, a tracing of it is made upon

straps now used, glass, and from this copy on glass as many

GEORGE Howe, or MANCHESTER, GEXother copies are taken in tracing-paper as TLEMAN, for certain improvements in ms. there are different colours intended to be chinery or apparatus for sweeping and used. From the tracing appropriated to cleaning chimneys and flues. Patent dated each colour those parts are cut out which May 9, 1842. are to be represented of that colour, so that, Two methods of chimney-sweeping are when superposed on the face of the picture, described. The first consists in effecting it covers all but those places where the co the operation by means of a brush and lour is to be applied, (exactly in the same chain; the chain passing over a pulley fixed way as in stencilling.) The colours are ap at the top of the chimney, and being attachplied in the state of an impalpable powder, ed by its two ends to two small windlasses mixed with just as much gum arabic or isin in the fire-place, upon and from which it is glass as suffices, when the colours are alternately wound and unwound. The second brcathed upon, or otherwise gently heated, method consists in bringing down the soot to fix the colours.

in a chimney by means of a sudden concus. ALFRED JEFFERY, OF LLOYD-STREET, sion of the air within it, which is to be ef. PENTONVILLE, GENTLEMAN, for a new fected by “hermetically sealing" the firemethod of preparing masts, spars, and other place, inserting a cylinder and piston, &c. wood, for ship-building and other purposes. JAMES ANTHONY EMSLIE, of NewcastlePatent dated April 15, 1842.

n-Tyne, C.E., for certain improrements is This method consists in the application of pumps. Patent dated June 9, 1842. a composition or glue for joining wood, These improvements relate chiefly to the which is stated to possess the advantages of class of pumps employed for the raising of being insoluble in water, and being more water from mines, through the agency of elastic than any glue heretofore in use. steam power. The patentee supposes the When a very elastic glue is desired, the pa case of water being raised from a depth tentee dissolves 1 lb. of caoutchouc in 4 gal of

seventy-five feet. He first takes lons of crude naphtha, frequently stirring a length of tubing, to the extent say of the solution, until the caoutchouc is well twenty-five feet. Upon the top of tbis dissolved, which will be in about ten or tubing, he places a box, of dimensions suitatwelve days; to this is added gum or shellac, ble to the quantity of water to be delivered in the proportion of two parts to one of at each stroke, which box is fitted with the naphtha. The composition is then put three valves ; one valve being at the head of

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