department at Woolwich (with which I have been more or less connected for many years) the utmost care and precision is observed in the manufacture of guns, and the proofs are so carefully made under the superintendence of competent officers as to render every gun or engine of perfect safety to the extent of 1,000 to 1,200 rounds of shot. Boilers and artillery are equally exposed to fracture, and it appears to me of little moment whether the one is burst by the charge of gunpowder, or the other by the elastic force of steam. Taking into consideration all the circumstances connected with the bursting of boilers and the bursting of guns, and looking at the active competition which exists, and is likely to be extended, in manufactories, railway traffic, and steam navigation, where it becomes every day more desirable to reduce the cost by an extended use of steam at a much higher pressure, it surely becomes a desideratum to secure the public safety by the introduction of some generally acknowledged system of construction that will bear the test of experience and involve a maximum power of resistance. The most elaborate disquisitions have taken place, by the most distinguished men of all ages since the invention of gunpowder, to discover the strength and form of guns of every description-surely boilers are equally if not more important, as the sacrifice of human life appears to me much greater in the one case than the other. It is, therefore, a subject of paramount importance to the public to know that the facts of scientific inquiry, and the knowledge of practical skill, have combined to give undeniable security as well as confidence, that boilers are properly constructed and capable of bearing at least three times their working pressure. On the question of explosions arising from mismanagement and ignorance, we have little further to add; and it now only retains to state that the subject of security from boiler explosions is of such importance as to call for more able exponents than myself. I have endeavoured to trace the causes of these lamentable occurrences, and to draw such deductions therefrom as I trust may be useful in at least mitigating, if not almost entirely averting, the danger. I repeat the means of prevention and the precautions necessary to be observed in the construction and management of boilers. 1st. To avoid explosions from internal pressure, cylindrical boilers of maximum form and strength must be used, including all the necessary appendages of safety valves, &c. 2nd. Explosions arising from deficiency of water may be prevented by the fusible alloys bursting plates, good feed pumps, water gauge alarms, and other marks of indication; but, above all, the experienced eye and careful attention of the engineer is the greatest security. 3rd. Explosions from collapse are generally produced from imperfect construction, which can only be remedied by adopting the cylindrical form of boiler, and a valve to prevent the formation of a vacuum in the boiler. 4th. Explosion from defective construction admits of only one simple remedy, and that is, the adoption of those forms which embody the maximum powers of resistance to internal pressure, and such as we have already recommended for general use. Lastly. Good and efficient management, a respectable and considerate engineer, and the introduction of such improvements, precautions, and securities as we have been enabled to recommend, will not only ensure confidence, but create a better system of management in all the requirements necessary to be observed in preventing steam boiler explosions. DEEP SEA SOUNDINGS. An Act of Congress authorises the vessels of the navy to co-operate with the scientific Lieutenant Maury, in procuring materials for his investigations into the phenomena of the "great deep." An order of the chief of the Bureau of Ordinance requires the commanders of our public cruisers to get a deep sea sounding whenever it is calm. Heretofore this had been a difficult object. The difficulty was in getting a line long enough, and in knowing when the plummet had reached the bottom Recourse had been had by other navies to wire of great length and tenuity, and the greatest depth over known to have been reached, before the subject was taken up here, was the sounding, by an officer of the English Navy, in 4,000 fathoms, which was by no means satisfactory. Lieutenant Walsh, in the United States schooner Taney, has reported a sounding without bottom, more than a mile deeper than this. Instead of costly implements used for sounding the depths of the ocean, our vessels are simply supplied with twine, to which they attach a weight, and when the weight ceases to sink they know it is on the bottom; and thus the depths of the ocean, in the deepest parts, may, without trouble or inconvenience, be ascertained in every calm of a few minutes' continuance. With this simple contrivance the Albany, Captain Platt, has run a line of deep sea soundings across the Gulf of Mexico, from Tampico to the Straits of Florida. The basin which holds the waters of this Gulf has thus been ascertained to be about a mile deep, and the Gulf stream in the Florida Pass about 3,000 feet deep. Captain Barron, of the John Adams, has been sounding the Atlantic Basin, between the Capes of Virginia and the Island of Maderia, belonging to Portugal. He got bottom with a line of 5,500 fathoms, the deepest, and 1,040 fathoms, the shallowest. Men of science will recognise in these results some of the most interesting and valuable physical discoveries of the day. They reflect the highest credit upon our navy and those who planned and set on foot these simple and beautiful arrangements, which have cleared away the difficulties with which all have found themselves beset who heretofore have undertaken to fathom the sea at great depths. AMERICAN PROGRESS IN PRACTICAL At the recent Meeting at Ipswich of the British Association, a description was read of "An Apparatus for Making Astronomical Observations by means of Electro-Magnetism," by G. P. and R. F. Bond, of the Cambridge (U.S.) Observatory. The apparatus exhibited has been in use at the Harvard Observatory, Cambridge (U.S.), and is the property of the United States Coast Survey. It consists of an electric breakcircuit clock, a galvanic battery of a single Grove's cup, and the spring governor, by which uniform motion is given to the paper. Two wires pass from the clock, one direct to the battery, and the other, through the break-circuit key used by the observer, and through the recording magnet, back to the battery. The length of the wire is of course immaterial. When the battery is in connection, the circuit is broken by the pallet leaving the tooth of the wheel, and is restored at the instant of the beat of the clock; which is, in fact, the sound produced by the completion of the contact restoring the circuit,-'the passage of the current being through the pallet and the escapement wheel alone. With the exception of the connecting wires, and the insulation of some parts, the clock is like those in common use for astronomical purposes. Several forms have been proposed by different persons, for interrupting, mechanically, the galvanic circuit at intervals precisely equal. In the present instance the clock is of the form proposed by Mr. Bond. Professor Wheatstone, Professor Mitchell, Dr. Locke, Mr. Saxton, and others, have contrived different modes of effecting this object:-the former several years since, but for a purpose distinct from the present. The cylinder makes a single rotation in a minute. The second marks, and the observations succeed each other in a continuous spiral. When a sheet is filled, and is taken from the cylinder, the second marks and observations appear in parallel columns, as in a table of double entry, the minutes and seconds being the two arguments at the head and side of the sheet. The observer, with the break-circuit key in his hand or at his side, at the instant of the transit of a star over the wire of a telescope, touches the key with his finger. The record is made at the same instant on the paper, which may be at any distance, many hundred miles, if required, from the observer. It is a well-established fact, that not only may observations be increased in number by this process, but that the limits of error of each individual result are also narrowed. As far as comparisons have yet been made, the personal equation between different observers, if not entirely insensible, is at least confined to a few hundredths of a second. It is through the facilities and means furnished by the Coast Survey Department of the United States, under the superintendence of Dr. A. D. Bache, that individuals there have been enabled to bring to its present stage the application of electro-magnetism to the purposes of geodesy and of astronomy, it having been at the expense of that department, and frequently by its officers, that nearly all the experiments have been conducted. Daguerreotypes of the Moon were shown, taken by Messrs. Whipple and Jones, of Boston, from the image formed in the focus of the great equatoreal of the Cambridge (U.S.) Observatory. The Astronomer Royal (Professor Airy) said, that the principle of the method was entirely the discovery of the Americans, and Professor Bond had the merit of originating what he had no doubt would prove of the utmost importance in the practice of astronomy: for besides the distraction of the attention of the observer at present having to listen to and to count the beats of the clock, and having then to occury many seconds in recording his observations when made, he could not often repeat these observations at as short intervals as would be desirable. But by this method he might even repeat an observation within the compass of one second, if required. It was also believed that there was a more direct connection between the senses of sight and touch, the senses that he required the aid of in this mode of observing, than there was between the senses of hearing and seeing, the senses called into united operation in the present mode of observing; and if this were so, what was at present known to practical observers under the name of personal equation, would be got rid of, if not entirely, yet to a great degree. These and other considerations had made him determine to give this method of observing the most mature consideration and the fullest trial. He had a cylinder constructed of twenty inches length and one foot diameter, and of which a fair conception of the size might be formed when he stated that it would gauge to about a bushel. This cylinder he hoped to be able to cause to revolve with something of an approach to astronomical uniformity. For this purpose, it was his intention to dispense with the fly-wheel which regulated the motion in Mr. Bond's apparatus, and to depend on a large conical pendulum revolving in a circle, the diameter of which would be about equal to the are of vibration of an ordinary seconds pendulum. This he intended should be a well-made mercurial compensating pendulum; and thus he hoped to be able to dispense with the clock used by Mr. Bond. The construction of the conical pendulum he intended to use was also peculiar. He intended to take advantage of the principle of the chronometric governor of the steam engine invented by a Prussian, and which the members of the section might see at work in Mr. Ransome's factory; but without such actual inspection, he feared he could not make himself understood in an attempt to explain this curious governor. Suffice it to say, that this governor was made to revolve by a bevel wheel, which engaged another bevel wheel attached to the governor, not directly, but through the intervention of a third, which worked upon a centre that was not entirely fixed. The moving of this intermediate wheel was made to work the valve which admitted or shut off steam, and thus equalize the motion of the machine as the resistance varied. In the apparatus he proposed to use, the resistance would occasionally vary from many causes, for instance, at the changing of the cylinder; and as this would affect the rate of the clock, if not provided against, he proposed to use the principle of the foregoing governor, by causing it to produce a varying by moving further out or nearer to the fulcrum of a steelyard a weight, which would thus increase or diminish, as was requisite, the friction caused by a point connected with the steelyard on a wheel kept revolving by the machine. In this way he hoped to be able to produce a motion which, under all changes to which the machine should be exposed, would remain uniform to the extreme accuracy required. Mr. Bond exhibited daguerreotypes of the moon, taken with the 23-feet equatoreal of Cambridge (U. S.) Observatory. These daguerreotypes were very beautiful, and admitted of being very considerably magnified. But Mr. Bond stated that the motion of the equatoreal, although very steady, was yet not sufficiently so to admit of their being examined by very high magnifying powers. Sir David Brewster stated that, if these daguerreotype impressions were taken on transparent sheets of gelatine paper, and so placed before a telescope as to subtend accurately thirty minutes of a degree, they would assume all the appearance of the moon itself. THE HAMMER SUPERSEDED IN BLOOMING IRON. At the last Meeting of the Birmingham Institution of Mechanical Engineers, a paper was read "On a New Machine for Blooming Iron." A complete working model of this machine in brass was exhibited, and also a sectional model in wood, which very clearly elucidated its action. The working portion of the machine consists of three eccentric, cuspidated, semilunarshaped cams, working simultaneously, and all kept rotating in one direction by wheels and pinions, firmly connected together in a strong frame, and set in motion by a steam engine. The convex sides of these semicylindrical cams are deeply grooved and serrated, and their peculiar form is such, that on dropping a bloom of iron into the concavity of the upper cam, as it presents itself, it is immediately drawn into the vortex, or centre of motion, of the three cams at the instant when that opening is the largest. As they rotate, the convexities, in consequence of the eccentricity of the centres, approach nearer and nearer-the ridges and rough surfaces squeezing, rolling, and kneading the iron in all directions, like squeezing a sponge in the hand. The cinders and impurities are thus ejected, and fall out beneath the machine; and the cams, in the latter part of their rotation, having closed the space between them to the smallest dimensions in the revolution, the bloom is elongated and ejected in the form of an iron cylinder. The paper stated that the machine was the invention of Mr. Jeremiah Brown, late of the Oak Farm Iron-works, and that its use was calculated to form a new era in the iron trade. For the production of superior iron, it had hitherto been considered that the hammer was indispensable; but for all purposes of efficiency, rapidity of action, and economy, this machine, it was assumed, would come into general use. From its strength and simplicity, it would not cost in repairs 201, a year; while a hammer involved expenses of ten times that amount, and the cost of replacing a broken hammer was well known in the iron trade to be a serious item. It turned out a finished bloom, entirely free from cinder, in twelve seconds, the engine working moderately; while under the hammer it could not be completed under eighty seconds. Thus, by the machine, the cylindrical bloom, when ejected, was still at welding heat, and could be at once passed through the rolls, while from the hammer it had again to pass through the furnace. In the discussion which followed the reading of the paper, Mr. Beazley, of Smethwick, the author of the paper, stated that, from some comparative experiments he had made, as to the strength of the same iron finished by hammer and by the machine, he considered the quality about equal; on different-sized bars, in some cases, they were a trifle in favour of the hammer, and in others of the machine; but he considered the economy highly important. In labour there was a saving of 1s. 3d. per ton; in tools of 1s. per ton; and the saving in time was equally worthy of consideration. That a more perfect ejection of the cinder was effected by the machine than by the hammer, was clear from the fact that the same quantity of iron weighed less after passing the former than from the operation of the latter; and Mr. Beazley said that he had taken two blooms direct from the machine succes sively, passed them together through the rolls; and the result was a perfectly welded joint. Mr. Adams bore testimony to the effiIciency of the machine; but he had seen a bloom passed through the rolls from it, and noticed that a considerable quantity of cinder still oozed from the ends. He thought, after leaving the machine, the iron might be subjected to a few blows of the hammer with advantage, and thus aim at the production of a highly superior article, rather than at saving 1s. a ton. Mr. Beazley thought the hammer would be superfluous, as the rolls effected what the machine had left undone. Mr. Cowper had often seen the machine in operation, and had not noticed the cinder in the iron at the rolls, as represented by Mr. Adams. Mr. Williams said, if iron was imperfectly puddled, the hammer would knock it to pieces and show the defect; but he feared the machine would roll the iron up, whether good or bad. From the rolling action, the cinder would be lapped up in the iron. He considered the cost of the machine and repairs would be an important consideration. Mr. Beazley assured Mr. Williams he was in error; it had been repeatedly proved that if the iron was imperfectly puddled, the machine instantly tore it in fragments; that, as to complexity, it was as simple as the ordinary rolls, and no more likely to get out of repair. It had worked four months with only one trifling accident, which arose from faulty construction at first. Siemens, Mr. Slate, and Professor Hodgkinson, also bore testimony to the efficiency of the machine. Mr. II. The system has worked well; for to its stimulating influence may be distinctly traced the unequalled progress which Great Britain has made in arts and manufactures, and all the wealth and power of which these have been the acknowledged source. Not a single branch of our industry can be named that has not had its origin in, or been materially aided by, patents. The steam engine, the cotton - spinning machine, the stocking-frame, the power-loom, steam navigation, railways, gas lighting, the hot blast, the electric telegraph, may be cited as notable and familiar examples. III. The maintenance of this system, so worthy of all respect for its antiquity, and for the important services which it has rendered to the country, is now (for the first time) hostilely assailed. The Bill (No 3), though professing only to amend the existing law, would in fact introduce so many new obstructions to the granting of patents, and so large a limitation of the privileges conferred by them, as practically to put an end to the encouragement and protection which they have hitherto afforded to men of inventive genius. For Firstly. It is proposed by the bill to grant no patent for an invention until a preliminary inquiry has been made by a Government examiner into the novelty of the in. vention, instead of leaving the novelty, as heretofore, open to subsequent impeachment. In all cases where the invention claimed is of no value, which is probably in nine out of every ten,-any such inquiry would be wholly superfluous. Secondly. No patent is to be granted until all the world has been invited, by advertisement, to come forward and oppose it; thus wantonly stirring up opposition where none might otherwise arise, tempting agents and servants to betray the secrets of their employers, and subjecting the honest and meritorious inventor to a system of espionnage at once offensive to his feelings, perilous to his interests, and wholly unnecessary for the public safety. Thirdly. The proposed preliminary examination would be of the most loose and unsatisfactory description, it not being proposed to invest the examiners with power to take evidence on oath, or to enforce the attendance of witnesses or production of books and papers. There is to be a right of appeal from the examiners to the lawofficers of the Crown, but neither are these officers to have any such judicial authority. Fourthly. The patent, when granted, is to extend only to England, Scotland, and Ireland, to the exclusion of the whole of the Colonial and Foreign possessions of the British Crown, -a distinction which would have the double effect of injuriously limiting the field of encouragement to the home inventor, and of depriving the excepted portions of much of that assistance which they might reasonably hope to derive from the continued application of scientific knowledge and mechanical skill to the development of their industrial resources. Fifthly. It is proposed by the Bill to increase in a majority of cases the cost, already enormous, of patents. The cost of a patent for England and the Colonies is at present 110%; the bill will raise it, without the Colonies being included, to at least 1757. Patents for Scotland and Ireland now cost respectively 751. and 1351.; but under this bill, neither could be obtained for less than 1751. The only case in which the cost would be reduced would be where an inventor desired to patent his invention for all the three kingdoms; then instead of 310l., he would have 1751. only to pay. But the cases are numerous where an inventor requires protection from one or two only of the three kingdoms. And sixthly. The bill proposes to make the use or publication of an invention in any part of the world previous to the grant of a patent for it, a ground for avoiding the patent; whereas, hitherto that penalty has attached only to previous use or publication in some part of the British dominions. A man may be reasonably presumed to be aware of what has been promulgated in his own country or its dependencies, but if he is to be held bound to know all that has previously been invented anywhere, so wide a door will be opened to pretexts for infringement, that it will be next to impossible to sustain any patent whatever; and a degree of uncertainty will hence result, which will be most disheartening to inventors, and be a great obstacle to the investment of capital in the promotion of patent inventions. IV. The sweeping and hazardous changes thus proposed to be made in the existing system for the encouragement of inventions, are wholly uncalled for by any pressure of public opinion, or by any proof whatever of its injurious tendency. Lord Granville, who was Chairman of the Select Committee of the House of Lords, from which the bill emanated, has frankly owned that public opinion is in favour of the system, in proportion of at least one hundred to six. The evidence taken on the subject before the Lords' Select Committee, has not yet (12th July) been printed; but when it appears, it will be found, it is believed, wholly insufficient to justify the conclusions founded upon it. The witnesses whose testimony is most relied on, are understood to have been |