Sir Robert Seppings, examined. Knows of no improvement as to safety that could be made in the steam vessels now in use by his Majesty, and now building for the King's service. They are filled in solid all the way up; their internal fastenings do not lie to a right angle, but to one of 45 degrees: a system of trussing is introduced, and all partial strength avoided; there is one uniform strength from stem to stern: a vessel only intended to carry passengers within a river, might be made slighter; but all steam vessels designed to go to sea ought to be of the same scantling as those in the King's service. Thinks that all merchant steam boats should be surveyed at least once every three years; not but what they may go five years without requiring to be looked at; but has seen ships launched side by side and built of the very same materials, and one has been unfit for service in three years, while the other has run for many years. Would leave it to the surveyors to pronounce whether a vessel was seaworthy or not; but would have a check for a vessel of a certain length, and then a certain degree of scantling for the size of the vessel. Hopes the committee will insist that all vessels shall be filled in, because there have been many instances where vessels would have gone down if they had not been so filled in. One of the Government steam-vessels, the African, going round to Portsmouth, got upon the Kentish Knock, carried away her keel from end to end, and a great deal of the plank at the bottom; but nevertheless she got round to Portsmouth without making little or any water, which was prevented by the plan of filling in witness recommends. The Gloucester was another instance; she struck on the famous rock off Gibraltar, and must have gone down but for having been built in this manner; she was very much shaken, but made no water. Thinks one day would be sufficient to survey a vessel, and ascer. tain if she was in a proper state, and that the expense would be nothing like £20. for a vessel of 400 tons. The boilers should, in some instances, be surveyed monthly; but not generally so.

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Does not see any necessity for making the bulk beads stronger than they already are in the Government vessels, because they are no part of the fabric of the ship. Would recommend that the frame-work of an engine should be clenched to the bottom of the vessel, and not on the sides.

Mr. Joseph Miller, engineer, exa. mined. Experiments are wanted to determine from the number of revolutions made by the paddle-wheels of a vessel, the rate of speed at which she is going; and thinks the problem an excessively difficult one to solve, because the speed will be effected by a variety of circumstances, as rough weather, draft of water, difference of current, weight of cargo, &c. In smooth water, between London and Gravesend, for instance, and in the case of vessels carrying passengers only, you might come to a very good calculation. Is not aware that the boiler and machinery of a steam boat stand in need of examination at fixed periods, when they are made by competent persons, and properly taken care of. The only danger is that of the boilers bursting, and in a low pressure engine, has never seen nor apprehended any danger from that cause. Has made a number of vessels for, the Channel service during the last fourteen years. The boilers are all made of iron, and generally last three years when in daily use. Knows of no way of reducing the power of an engine, but the ordinary one of shutting the throttle valve, and shutting off the injection; and does not think it would be easy by this means to come to any exact number of knots-say from nine to six. It would, in every instance, require some time, and a number of trials, before an engineer could change from one fixed rate of going to another fixed rate. Vessels almost always work with the safety valve on the lift; they' use all the pressure they can get; and have no spare power to use on an emergency without passing the limit of safety. When the throttle valve is fully opened, and the safety valve on the lift, the engine is at its utmost power, providing the barometer is standing at the same time at its greatest height, because it is not the pressure of the steam, so much as the vacuum that produces the power. The height of the barometer varies with the pressure of the atmosphere; but in ordinary cases, the extreme height is from 27 to 28 inches of mercury. An index might be attached to the throttle valve, the movements of which would denote the speed of a vessel, if the resistance were always the same; but a difference in the number of passengers merely will

cause a difference in the dip and draft, both of which would operate against the speed of the vessel. Low pressure boilers are so much stronger than any steam to which they can be subjected, that it is never thought necessary to prove them in any way before putting them on board. The terms high and low are, however, differently used in different places. The engines used in Cornwall are called

high-pressure engines, though generally they are not worked at a higher pressure than 15 lbs. to an inch on the boiler; but in America, they would consider that a low pressure.

(To be continued in our next.)

ADCOCK'S ENGINEERS' AND ARCHITECTS' POCKET BOOKS FOR 1832.

We are once more under the painful necessity of putting our scientific friends on their guard, against the species of literary jugglery which continues to be annu ally perpetrated under the above titles. We would use softer words, if we knew of any others that would sufficiently characterize the description of offence of which Mr. Adcock is guilty. When this annual (for the two books are but one, with a slight variation in the titles) was com menced in 1829, we were at the pains to show, at considerable length, that most of the tables, on which it rested its chief claims to utility, as an Engineers' or Architects' Vade-mecum, were so full of gross blunders, that no dependance whatever could be placed upon them in practice.* We pressed on the author the necessity of subjecting his work to a "strict and thorough revision;" and this with a feeling of perfect good-will towards him; for we commended at the same time, in the warmest terms, the spirit of usefulness in which it was conceived, and the labour already bestowed upon it. Mr. Adcock, however, chose to pay no heed to our strictures or admonitions. His Pocket Books for 1830 appeared with the same plentiful crop of blunders, as those of 1829; not one of the several thousands which we pointed out had he condescended to correct or expunge: his books, though put forth as things which no engineer or architect should be without, were still as useless, for all practical purposes, as ever! An-1

other year came round, and brought with it no change!! And now, on the eve of 1832, we find the same identical dish of defects unblushingly and impudently served up for the fourth time to the scientific world!!! Is not this, to use a celebrated phrase, too bad ?"

It may be, that the Pocket-Books for 1829, 1830, 1831, and 1832, are not different editions, but one edition with a mere change of titles-that four years have not yet exhausted the impression which was intended for one; but if the case be so, Mr. Adcock might, at least, have added to the books issued for 1830, 1831, and 1832, a few pages of corrections; the binding each year has been new, though the printing may not. it may be, that the work was stereotyped before its errors were detected and exposed; if so, Mr. Adcock is still less to be excused; for in such a case there could be but one honest course to pursue, and that was, to put his plates into the melting pot forthwith.

NOTES WORTH NOTICE.

Or

"Without light, planets are colourless; without publicity, facts are useless."

Cultivation of the English Language. -It is an astonishing fact, that since May, lumes have issued from the native press of 1825, no less than from 40 to 50,000 voIndia; and it is calculated that there are nearly 200 young natives in Calcutta, of the higher classes, to whom the English language is as familiar as their own mother-tongue!

British Science displayed Abroad.The ornithology (why not Bird-ology, which would be quite as plain?) of America seems likely to continue under heavy obligations to British enterprize and skill. The work of the humble Scotch mecha-* nic, Alexander Wilson, forms a noble foundation-stone for the science in the Western Hemisphere. Audubon, the worthy follower in Wilson's steps, is, we believe, a native; but Mr. Thomas Nuttall, who has lately announced, A Compendium of American Ornithology, the appearance of which is looked for as likely to enlarge the stores of knowledge on this interesting subject in a very eminent degree, is, like Wilson, a "Britou born."

Statistics of the State of New York.-, The New York Annual Register for 1831, contains a statistical table, from which it appears that in one State 237 news

papers are published, which are supposed to issue annually 14,536,000 printed sheets! Population, 1,500,000, of whom 50,000 are Blacks. The learned professions seem pretty well stocked :-number of clergy, 1382; lawyers, (counsel and attorneys) 1741; physicians and sur. geons, 2549,

Symptoms of Decline on the Continent -The most celebrated scientific and literary journal of Germany, the Hermes, has been recently discontinued, after an existence of 13 years. As among its contributors were numbered the most eminent scientific characters of the Continent, its failure seems to bespeak a "decline of science" elsewhere than in England.

Moveable Houses.- Mr. Michael Rough, whose plan for preserving houses from the effect of wind appeared in a late Number of the Mechanics' Magazine, is not the only person who has turned his attention to something of the kind, although his plan is perfectly novel and original. A Swedish engineer, named Blom, has for some years been endeavouring to introduce a method by which wooden houses may be so constructed as to be moved at pleasure, something after the fashion of a piece of furniture. He asserts, that his invention has been already adopted with perfect success in his native country; but his ideas have been received with so much ridicule and mistrust by most persons out of it, that he has at last been induced to declare his intention of satisfying all doubts by erecting a moveable mansion in France! Why not export one from Sweden ready-made?

A Modest Proposal.-Doctor Brewster, it appears, not satisfied with origi nating "The British Association for the Cultivation of Science" (vide last Notes worth Notice) has another grand scheme upon the stocks, the details of which are to see the light in the next Number of his Edinburgh Journal of Science! The Reform Bill does not meet his entire appro bation, because it provides no representa tives of the philosophy of the nation; and this defect he proposes to remove by introducing a clause, giving to each scientific body in the kingdom the privilege of sending one member, to be elected by the "Fellows!" The idea is a good one; but it does not go far enough, We would have every editor of a scientific periodical entitled to a seat by virtue of his office! We hope Dr. B. will attend to this humble suggestion-if he does not think his scheme ridiculous enough already.

Spread of Knowledge. - Family Libraries are to the full as common in the

.

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United States as in England. Most of ours are reprinted there, and they have one or two partially original. An American Society for the Diffusion of Useful Knowledge has also been formed, and the first volume of its publications has appeared. It consists of a curious medley of introductions and persuasives to studyhalf original and half copied: the Lord Chancellor's "Objects, Advantages, and Pleasures of Science," being balanced by "Judge Story's "Discourse on the Pursuit of Knowledge ;" and Sir John Herschel's Introduction to the Study of Natural Philosophy," by Mr. Edward Everett's "Address to the Mechanic Institution!" In the opinion of Brother Jonathan himself, the merits of the rival treatises are quite on a par. Among numberless other useful works, "Knowledge for the People, or the Plain Why and Because, is now regularly reprinted at Boston.

46

Iron Manufacture in India. - In a former note, we mentioned that exertions were making to procure iron from the ore. in our Indian possessions. This desirable event has at length taken place, as appears by the following letter, which is taken from the Madras Government Gazette, of June 23. Having been on duty, the 16th June, at the station of Porto Novo, I cannot refrain from bringing to your knowledge and information, the gratifying sight I experienced in witnessing the manufacture of the first cast-iron ever produced in India. Being present at what I termed the tapping of the furnace, I beheld in a moment a pure and liquid stream of castiron running like water. The European workmen as momentarily gave the hearty English huzza! in which I as heartily joined. This casting of iron weighed three hundred weight, of which I send you a sample with the cinder, which is pure glass. The new Indian iron-furnace having now, so honourably to her founder, so wyll discharged her duty, I should obserye, what is not less worthy of remark, that this cast-iron has been produced from it within one month from the foundation having been laid."

Botany Bay Improvements. A new species of timber has been discovered in New South Wales, which is said to possess the colour and grain of English oak, and, as far as trial has been made, hitherto to possess the same valuable properties. The discoverer is about to enter on the manufacture of casks on an extensive scale, with this material, which he has appropriately designated "Australian oak." The first Australian steam-vessel,

the Sophia Jane, commenced running on the 17th of June.

New Compression Pump. If we can believe what we are told of a new French invention, Messrs. Perkins and Shalders may both hide their diminished heads. This is a "compression pump ;" it acts by means of the compression of gas, and the inventor, M. Perrot, asserts, that such are its advantages, that, "by the new pump a single man may perform as much work as a steam engine of thirty horse power, applied to the old pump!" Its last application is to a gun, which propels two hundred balls a minute.

F. H.

Cast-Iron Ornaments.-Sir, Can you, or any of your correspondents, inform me, whether there are in London any casters of iron after the fashion of some of the French bracelets, 1 have seen in the shops a specimen of the Lord's Supper, in alto relievo, executed in cast-iron, with a sharpness and fidelity equal to plaister of Paris. I have been informed that they are made at Berlin. If there are no artists here, perhaps some one can inform me what is the exact process used in casting.-Yours, &c. J., Dec. 18, 1831.

Locomotive Controversy.-Sir, I beg leave to observe that there is an error of the press in your last Number, which materially injures the sense of a passage in my communication relative to Mr. Bad deley's mistake. The sentence should read thus:"The action and re-action which Mr, B. describes are between parts of the same machine, and not be.. tween the machine and the road." The words in italics were omitted. I beg also to say, that the allusion to your correspondent, S. Y., was in reference to his letter to Saxula, and not to his notice of Mr. Baddeley's error. He has since said, that he stands nearly, if not quite alone, in his opinions on the locomotive controversy. I have yet to learn that he has brought forward any thing on the subject, whether it be true or false, in which he was not anticipated by others. This gratuitous assertion of his, as well as his mere ipse dixit on Mr. Baddeley's mistake, is neither very interesting nor very instructive.-A, Z. Ibid." I find myself much edified by the magiste rial decision of A. Z. upon the merits of your various correspondents, and shall feel obliged by his inform ing me who told him the dispute between Saxula and his opponents was what he has done to represent it, or if not told, where he learned the fact."S. Y.

swer.

Jones's Iron Wheels." As I seldom go to Lon don, I have no opportunity of seeing Jones's Patent Wheels; consequently, I do not know how they anBut I think an improvement might be made by substituting chains instead of bars for spokes.”A Farmer-Forest of Dean, November 7, 1831.[Mr. Jones's wheels answer so well that they are now getting into very general use. Our Gloucestershire correspondent will find a full description of them in the Mechanics' Magazine, vol. ix, p. 210. ED. M. M.]

Sail-worked Paddles." In the Mechanics' Ma. gazine for the month of November, I observe a plan by A. B. W. for assisting the motion of a ship by sail-worked paddles; and in the succeding pages two claims entered for the same invention. I believe I can in my own person furnish another exemplification how the same idea may enter into the brains of different men, situated many miles apart. It is now two years ago since I had a small boat built which I intended to propel with machinery similar to that of the old-fashioned jacks

for roasting meat, and vanes something like a windmill; but for want of the necessary tools, I was obliged to lay the design aside."-1BID.

Transit of Mercury. The last time this phenomenon was observed, fell on the 9th November, 1802, and was remarkable from the delight which it afforded to the closing days of Lalande. "The passage of Mercury over the sun's disc," he says, "was observed this morning for the 19th time. The weather was exceedingly favourable, and astronomers enjoyed, in the completest manner, the sight of this curious phenomenon. I was the more anxious to have a view of it, as I shall never see it The gratification he experienced, arose from

more.

finding that his tables, the result of forty year's la

bour, had reached the utmost perfection which they can attain in the present state of science. Lalande wisely confined himself to his astronomical studies during the heat of the revolution; and, when he had consequently escaped the fury of the times, he jocosely said, I inay thank my stars for it."- United Service Journal. The next transit, as our readers are aware, will take place on the 5th May, 1832.

Temperance Societies.-The quantity of squibs and crackers with which we have been assailed on account of the opinion we have expressed of these Institutions, and particularly of our taking pleasure in the support of Junius Redivivus, is quite amaz ing. We make our bow to" Anacreon" and "Giles Fillpot," they are good marksmen, and mean no harm; as for the rest, they are chiefly of that order in pyrotechnics, typified by the serpent-good at a hiss, and nothing more. How is it that none of these buzzers venture to assail our positious in good earnest, and with real powder and shot? One of them, who takes the title of "Anti-Humbug," (as if all the humbug were not the other way) has fallen upon a strange mode to give vent to his spleen. A" Sonnet to Junius Redivivus!" A sweet sonnet, of all things in the world! We subjoin a specimen of this odd variety in polemics :

"See Junius here, the advocate of gin,
(Or some dull donkey in that lion's skin)
See here, to plead the cause of rum,
Great Junius, from the shades has come;
Ile, too, defends inspiring brandy,

In his esteem, it seems to stand high."

We desire to except from the preceding observations, a reply which we have received from T. M. B., and for which we regret we have not room this week; also a very well written letter, signed "F. W. G." in which the writer, alluding to the personalities, which Junius Redivivus has so lavishly and, as we are free to confess, so improperly indulged, sensibly observes: "Whoever wishes to submit his views to the public, should recollect that the public are only so far interested as the cause of truth is served, and that he must not look upon every one who questions his opinions as an intellectual gladiator, whom he must get rid of at whatever hazard; but as one, seeking, like himself, his own information, and the benefit of others, and with whom it would be manly, as well as wise, to agree to differ."

INTERIM NOTICES.

Cominunications received from Mr. MackinnonMr. Hirsch A Labouring Mechanic-B. F. F.T. M. B.-S. Y.-F. W. G.-Junius RedivivusII. C.-Mr. Baddeley-Mr. Davy- Mr. Sharp-F. B.-A Reader-Mr. Rough-G. L. S.

LONDON: Published by M. SALMON, at the Mechanics' Magazine Office, Wine-office-court, (between 145 and 146) Fleet Street, where Com. munications (post paid) are requested to be addressed. Sold by G. G. BENNIS, 55, Rue Neuve, St. Augustin, Paris,

M. SALMON, Printer, Fleet Street.