THE visually, and as to the "hammer" test it is a made square only shows how extensive is a bad practice. Every competent mechanic knows that turning corners of journals or bearings MECHANICS' MAGAZINE. pair of heavy wheels on it, and it is support- of any kind sharp makes the shaft at that LONDON: FRIDAY, JULY 1, 1870. THE NEWARK COLLISION. NEV across at the corner. The fact of the flaw all round the circumference testifies at once to the evil of sharp corners, and to the excellent quality of the axle in standing so long. ing a matter of five or six tons; besides, the point quite ten per cent. weaker than if the wheel strikers could not, even if they wished, shoulder is well rounded off. This very strike the axle itself under these conditions accident proves the truth of the matter. without getting beneath the waggon for the Here, as Captain Tyler tells us, is a flaw purpose. All they strike is the wheel, and surrounding the axle at the fracture; we are they very properly do not trust to the sound told the fracture is at the wheel boss, and TEVER does a journalist feel his task so of one of a pair of wheels; they test them Mr. Sacre tells us that he had to scrutinise painful and irksome as when he is individually, and if so, it will be fair to the axle closely to determine if the shoulder called upon to review a disaster which en-assume that striking either wheel will not go was turned square. That proves pretty clearly tails the destruction of human life and health. far, though it may help a little to test the that the axle broke just as one with a sharp With the terrible catastrophe of Abergele axle. The question of fatigue leads us to corner might be expected to do-straight yet fresh in our memories it devolves on us to notice another almost as lamentable. The late disaster on the Great Northern Railway, unlike that in Wales, is terribly simple, so totally unforeseen as to have a very humiliating effect on the minds of engineers. The facts can hardly be more simple. An excursion train from London, consisting of four sections, one destined for each of the principal towns of Yorkshire, meets an up goods train at about three-quarters of a mile from Newark. Just immediately before the two trains meet the axle of one of the waggons in the goods train breaks across, and after that waggon has jolted and stumbled some score or two of yards it throws seven waggons that are behind it across the down line and the "six-foot" but a few seconds before the excursion arrives there, and almost in a second several of the hapless travellers, some asleep, some chatting over their day's pleasuring, are plunged into a scene of death and disablement. From the evidence given before the coroner it is incontestably proved that none of the officials in charge of either train were in any way to blame. It has been proved that the Iriver of the goods train had scarcely discovered the nature of the mishap to his own train before the excursion train was wrecked upon it. From all the evidence, and especially from Captain Tyler's, as well that given by him before the coroner as that embodied in his elaborate report to the Board of Trade, we have little room to doubt that the primary cause of the catastrophe was the fracture of an axle of one of the goods waggons. There is no evidence to justify us in supposing that any part of the train had left the rails until after the axle had given way. Captain Tyler's description of the manner in which the ground and the sleepers were marked and torn for some distance in the rear of the goods train indicates the action of the unsupported end of the broken axle before it had broken away from the axle box at the other end and fouled the trailing axle. some of the evidence adduced before the crack. acted on by the strain of the wheel rubbing round the curve, and that strain acting at the flaw with all the leverage of the radius of the wheel, the only wonder is the axle did not fail months before. The existence of the flaw at that particular place could not by any possibility have been detected by sight, unless the wheel had been removed, and as we have already stated it was unlikely to be discovered by striking the wheel. That, indeed, is no matter of theory, because we are told the wheels were sounded scarce an hour before. The fracture raises a somewhat curious We point in the durability of axles-that is, the From the evidence before us it is clear that the detection of the flaw which caused the disaster was wholly impossible without removing the wheel, and even after that we believe the place would have to be skinned a little in the lathe to discover it. There is The question presenting itself for our con- one point in Mr. Sacre's evidence which at sideration as engineers is, How, if sound once arrests the attention of a mechanical enimmediately before, the axle could so sud-gineer; it is the following statement: He says, denly give way? or how, having an extensive The broken axle is 3in. diameter at the flaw in it at the point of fracture, that axle centre, up to the boss 44in., inside the boss or came to be there at all? There are three through the wheels 3 15-16in." Immediately ways by which an axle may fail: the first after, he says, "The shoulder of the broken Before concluding, we must touch on two would be from bad material, the second from axle is turned square, as far as I can tell points; the one is, that we consider Captain flaws, the third from what we may call from close inspection." We believe this Tyler's remark about the importance of a "fatigue." From the extreme care exer- statement, coupled with other evidence, complete register being kept of all rolling cised by railway companies the use of bad makes the nature of the failure clear, but stock, a perfect history, in fact, of each vehicle material in their own rolling stock is reduced we confess to a feeling of both surprise and and its leading parts, is an excellent one. to a minimum; we say their own rolling sorrow to hear such a statement. The The second point we referred to at the comstock because we have more to say about axle in the boss of the wheel is more mencement of this article, and it is the that presently. The presence of flaws can than half an inch less than that part imme-difference between the rolling stock of the be detected with tolerable though not with diately behind the wheel, or a quarter of an company themselves and that of private firms absolute certainty by close scrutiny and by inch of shoulder. Well, that is as little as or of individuals. We should certainly like to "ringing with a hammer." If the flaws are could well be allowed in forging an axle for external, too, they may be detected by "machining," a place for the wheel boss, and scratching the surface of the axle carefully to cut out any mark or superficial defect, but with a steel instrument, though this is un- we must ask the question, How was it that certain as a test, because the inequality shoulder had a sharp corner instead of being revealed by this may be entirely superficial. as-if the foreman who had charge of the It is easier to test axles in the workshops turning of the axle in the lathe knew his and without their wheels than after they are mounted and fitted to the waggon; easier, whether the test be by sight or by sound. There are better facilities for examining them business it would have been-rounded well know the provisions made by railway companies to secure that private rolling stock is as carefully constructed and repaired as their own. DURABILITY OF IRON. THE very recent lamentable catastrophe on the Great Northern Railway leads the mind to reflect very seriously upon the important subject of the durability of iron when exposed to constant and severe ser- and the case becomes altered to a dynamical number of revolutions, then the life of the vice. Without entering upon the recondite instead of a statical force. The vibration of axle is evidently proportional to Nx V, and abstract question respecting the assumed the floor or platform upon which the tests and for the same sized axle made of the same change that is supposed to occur in the are carried on is quite sufficient to affect the metal the equation N x V should be a molecular arrangement of the material when results in this manner. It thus was impos- constant. The state of the road run over subjected to continual strains, common sense sible in some of the experiments under con- would also seriously affect the result, and in tells us that the result of wear and tear is the sideration, to determine whether the fracture fact so many other agencies and contingencies same in every thing: and whether the object of some of the bars was brought about by would spring up that the accurate solution of be a rail, an axle, a wheel tyre, or human being the direct statical pressure, or whether it the question would not be practicable. The deterioration is the inevitable consequence of occurred in consequence of any sudden vibra- conclusion to be arrived at from a consideraexposure to wear and tear. Of all materials tion being imparted to the whole arrange- tion of the facts points unmistakably to the belonging to the art of construction iron, ment. The effect of any long-continued observation made by the inspecting officer of whether cast or wrought, is that which shows pressure or repeated strain of any kind upon the Board of Trade, Captain Tyler. He releast superficially the actual condition of its any material will obviously be to weaken the marked that some better register should be internal structure. It is a simple matter to cohesive force, and thus gradually destroy kept of the mileage run by the waggons and detect the incipient signs of impending the resisting capabilities of the body. carriages of the trains, so that there might failure in timber, brick, and stone, either in In those instances in which a bar is be some idea of the period at which a wheel the mass or in detail, but the case is far tested a l'outrance, its resistance is readily or an axle might be fairly presumed to be otherwise where iron is concerned. More-appreciable by the deflection. Evidently the nearly hors de combat. At these stages a more over, that material has been, comparatively greater the load the greater the deflection. stringent and careful examination of them speaking, so recently introduced upon a large But it was demonstrated by the bars sub- should be made, and thus a more precise scale into the art of construction that literally mitted to test by Sir William Fairbairn that knowledge of their condition would be obthere has not yet been time enough to form with a constant weight time produced the tained than that which is arrived at through even an approximate judgment of the period same result that a gradually increasing load the medium of the eye and the ear. of its durability. This period will naturally would have done immediately. Thus with a depend upon the nature of the service to given load one of the bars broke at once, which it is subjected. Prima facie, a wheel of while another of the same dimensions bore a locomotive in constant service, and the the same load for more than thirty days. parts revolving with it, certainly appear to Unfortunately it was not determined whether undergo the maximum amount of wear and this last fracture was the result of accident ERHAPS with the exception of Belgium, tear that could fall to the lot of any moving or vibration. It is impossible, having a which has aptly been termed "the antebody of a similar description. It has really proper regard to these facts, to prevent arriv-room to Europe," there is no country where no rest, for when not in motion it has to ing at the conclusion that time and a con- greater variety of coins is intermixed in the carry the weight placed upon it. Motion stant exposure to strains and loads must in channels of general circulation than in Canada. and deterioration are synonymous terms, for the long run very materially contribute to- From its contiguity to the United States, and the former is the inevitable precursor of wards the deteriorating and literal wearing the constant intercommunications of a comfriction, which is the destroying angel of all out of the material. The effect for a short mercial and trading character between the terrestrial objects. Had the necessity of time may be completely imperceptible and inhabitants of America proper and British friction as one of the laws of nature been impossible of detection by the most refined America, dollars, cents, dimes, and other properly recognised by those who sought agents of skill and analysis. But neverthe-denominations of States' money are freely after "perpetual motion," the lives and for-less the evil does progress. Insidious and used in Canada. Then, as the old French tunes of many clever and ingenious men slow in its first advances, it is not the less element of population largely exists in various would not have been lost in the manner they sure in its final accomplishment, and that have been. Without taking into account the which at the commencement was barely perquestion of motion, the subject of the effect ceptible becomes at last but too forcibly proof a long-continued pressure or strain upon minent. If we suppose the flaw that was a bar or beam of iron may be regarded in a discovered in the broken axle of the waggon purely statical sense. In plain language, in the accident to which we allude to have suppose, for sake of example, an upright been the final climax of the successive jerks pillar loaded with a weight duly and safely proportioned to its ultimate breaking weight will the pillar carry this load ad infinitum? It is of course taken for granted that no disturbing agent arises to interfere with the assumed statical state of affairs. NEW COINAGE OF SILVER FOR PER parts of our Canadian possessions, the coins of the French empire are also in extensive use. English money, of gold, silver, and bronze, is as freely circulated as at home. In addition, the coins peculiar to Canada, and consisting of 20 cent, 10 cent, and 5 cent pieces of silver, together with 1 cents of bronze, and bank tokens of copper, jostle with the other varieties, and make up a heterogeneous whole. It might be imagined that the introduction of a new coinage of any kind would but intensify the general medley, and make account keeping yet more difficult. The Canadian authorities, however, think otherwise, and a little explanation will make it pretty clear that they are right. and violent strains to which it was subjected during its myriad revolutions, a little calculation will demonstrate how imperceptible must have been its gradual culmination. We assume that directly the waggon was started running the cause of ultimate destruction Some valuable experiments were under- commenced to work. According to the taken many years ago by Sir W. Fairbairn, evidence given at the inquest this waggon with a view to obtain a practical solution of had been in active service for the last the problem. It cannot be said that the eighteen years. No record was kept of the The dollar of America circulates at the results arrived at by him were strictly con- number of miles it must have travelled dur- rate of 4s. 2d. English, and its subsidiary clusive, but nevertheless they are extremely ing that time, but it was estimated that denominations-the half dollar and quarter interesting and instructive, and furnish the about 230 miles per week was a fair average best existing data respecting the matter. for the distance run by the ordinary goods One of the first results of these experiments trucks and waggons. The diameter of was to upset the theory held by previous the wheel may be taken at 2ft. 6in. If the writers on the transverse strength of ma- calculation be made upon this data it will be terials. They considered, and, in fact, found that this axle made the astounding asserted, that the resistance of cast iron was number of 144,668,160 revolutions during restricted to the limits of the strain which its life time. Supposing, for the moment, would produce a permanent set. Upon this that the destroying agent did not commence hypothesis it would not be safe to load the until some time after the waggon had commaterial with a weight greater than one-menced running, yet who can possibly tell third of that which would cause its fracture. when it did begin? It is much more rational It is questionable if it would be judicious to to regard the flaw as the result of a succesload cast iron as a rule in practice to a third sive repetition of the same cause than to of its breaking weight even with a statical suppose that it arose from a sudden and load, although in the experiments referred to single one. The opinion was expressed at some of the bars were loaded to within a the inquest that the flaw must have existed tenth of the weight that would break them. about six months prior to the fracture of the In all experiments of this character it must axle, but this was merely an opinion and it be borne in mind that it is impossible, in would be impossible to prove the date spite of every care, to assimilate the condi- of its first existence. Our information tions precisely to those which prevail in upon this particular subject is very scanty. actual practice. A very close approximation It may be said to be nil. It would be very may often be obtained, but an exact identity desirable to know what part the velocity, is impracticable. The difficulty that arises that is, the number of revolutions in a given in subjecting bars of cast or wrought iron to time, plays in the matter. If it be assumed a long-continued statical load is to ensure that after a certain time the axle will be a complete absence of any vibration, for if this element be allowed to be introduced into the experiment the result is at once vitiated, destroyed independently of the velocity, dollar-of course represent respectively 2s. 1d., and 1s. d. These fractional divisions make the interchange of florins and shillings with the American coinage awkward and troublesome. The expedient, therefore, is being resorted to of coining, and introducing into Canada English pieces, which shall be of precisely equal value with the half dollar and quarter dollar of the United States. As Canada has no mint of its own, the Royal Mint, in London, is under requisition to produce the new members of the coinage family for that country. Accordingly, the presses at Tower Hill are at this moment engaged in stamping into existence the lustrous, if not illustrious little strangers. The work is certainly of a more legitimate nature than that of minting tokens for foreign countries, as lately recommended by the Chancellor of the Exchequer. The new Canadian coins are to be known as 50 cent, and 25 cent pieces, and in size they do not vary much from our own florins and shillings. They are of the same standard of fineness, but contain, each, the extra amount of metal necessary to make their intrinsic value co-equal with that of the half and quarter dollar. So far as design and ornamentation go, the Canadian coins will bear minute criticism, and they are likely in all ways to become popular when they reach their transatlantic destination. The obverse and reverse of the 50 and 25 cent coins are fac-similes of each other, and they differ only in dimensions. The head of her Majesty seen in profile is the principal device on both denominations of money. It is admirably engraved, whilst the resemblance to the Queen, not as she was twenty years ago, but as she appears to-day, is most faithful. The face, as depicted on our own silver coins, is turned towards the left, and the brow is encircled by a tiara, copied from a richly jewelled and highly chased original. The hair gathered at the back of the head in classical and antique form presents a pleasing contrast to the style known as that "of the period," and which disfigures the fair sex of the present time. Flowing and wavy ribands attach the tiara to the Royal head, and constitute a graceful completion of the picture. The legend surrounding the bust of her Majesty is "VICTORIA DEI GRATIA REGINA," and below, in bolder characters, is teration? over the point at which the bale is to be Having given some description we will If we assume the barrel to be 32in. long and 7in. in diameter, which is a common size, and the rope to be or dotted border is seen within the protecting (ropes being spoken of by circumference), we the word "CANADA." A very fine engrailment the usual dimensions, known as "three inch," edge, which latter, as in most of our own have it about Îin. diameter; this will give 32 coins, is too narrow and wiry to make its tech-coils on the barrel in one layer, equalling nical title other than a misnomer. When will 32 x 2, or 64ft. of rope, because the diameter it be learnt by those who order such matters of the barrel is 7in., that of the rope lin., that "protecting edges" on coins should be equalling 8in. diameter, which multiplied by bold and broad rims capable of resisting the 3 gives 24in. or 2ft. Most generally this rough ordeal of circulation and of preserving traverse is sufficient, though occasionally in the artist's work from defacement and obli- large ships a second coil is wound on the barrel for half its length, giving a little in excess of 32ft. more, say 40ft. The diagonal winches run 30 to 35 revolutions of the barrel per minute, and this with a gear of 6 to 1 would give 180 to 210 double strokes of the piston in the same time, or with a stroke of 10in. equalling 300ft. to 350ft. of piston per minute, which is pretty well when it is considered that a common area of rubbing face for a guide block in some of these engines is but 4 square inches, while a length of connecting rod of 1.75 of the stroke is very usual. This speed of gear moves the load on the first coil of a 7-inch barrel at the rate of 60ft. to 70ft. per minute. A load of 30cwt. is very common for one of these engines, and this load at 60ft. per minute gives about 6 indicated horse power of work done in this alone, neglecting all sources of loss otherwise. As practical examples we cite the following, omitting names of vessels. An engine on board a large Australian liner has cleared out 1,345 tons of general cargo-by measurement not by weight-in 58 working hours, with an average consumption of 2.75cwt. of Yorkshire coal per day, working 7 hours per day. The load raised of course varied considerably and constantly, but 35cwt. was the maximum, save in some very exceptional instances; assuming, however, an average of 25cwt. and also assuming the barrel to have made 30 revolutions per minute on the average. The diameter of barrel was 7in., the engine geared very nearly 4.5 to 1, the number of teeth in the wheel being 68, and those in the pinion reckoning 15; this, taking for sim The reverse of these virtually half, and quarter dollars is made up of an exquisitely designed and executed wreath of maple leaves. The crenated character of the foliage of the maple tree, which grows in profusion in Canada, and is, therefore, peculiarly appropriate as an emblematic device in this instance, is very favourable to artistic design, and the engraver has here made the best of the material. The maple wreath is refreshing to the eye after those of the oak and laurel which have been so often pressed into the service of the medallist and the coiner, and which have hence become hackneyed to a painful degree. Within graceful encirclement of the maple leaves is the inscription "50 cents," or "25 cents," as the case may be, and the date "1870." The British crown appears between the terminal points of the wreath, and ribands tied in a flowing bow unite its stems underneath the date. A border and edge similar to those of the obverse complete the design of the reverse side of the coins. The circumferences are "milled," after the manner of British silver a combustion chamber, and about 26 return tubes 24in. outside diameter, the smoke-box being over the firedoor. On the next voyage of this ship 1,800 tons of cargo was cleared out at an Australian port in 97 working hours. An engine of the same kind fitted on board another Australian ship cleared out 1,800 tons in 51 working hours. A diagonal double cylinder winch fitted with frictional instead of toothed gearing, the diameter of cylinders 7in., and length of stroke 10in., loaded 600 bales of wool in 5 hours, each bale averaging 350lb., or in round numbers 94 tons, with a roughly estimated consumption of 1.75cwt. of coal. In all these estimates of the number of tons hoisted in a given time it is well to state that the engines were standing at frequent intervals for the hooking and unhooking of the loads. LIGHT GOLD. of the Bank of England in reference to light A TREASURY letter of the 21st ult., addressed to the Governor and Company gold coin, is not unworthy of notice, although it is questionable to us whether, so far as practical results are concerned, it do not prove "a dead letter." The object intended to be effected by the arrangement made between the Government and the Bank is the withdrawal from circulation of the thousands of light sovereigns and halfsovereigns which undoubtedly are now in circulation. This is sought to be accomplished by offering a higher price for such coins than has hitherto been given, namely, £3 17s. 9d. instead of £3 17s. 6d. per ounce. As, however, the practice of weighing individual coins is seldom or never observed, except in the various banks of the United Kingdom, and few people care whether the sovereigns and half-sovereigns they may be fortunate enough to possess are a grain lighter or heavier than the theoretically legal weight of such pieces, it is not at all probable that much trouble will be taken by their holders to sell them at a loss as mere bullion. It is much more likely that they (the coins) will continue to float about the creeks and channels of circulation and pass at their nominal rather than intrinsic value. As it is, the Bank of England usually receives and stops the circulation of about two millions of light sovereigns every year, and the mere fact that that establishment intends offering, on and after July 1, 1870, an extra premium of 24d. per ounce for such coins, is not calculated to add very largely to their influx to the Bank. The proposition, nevertheless, is a harmless one, and there is no reason why the Mint should not receive worn sovereigns instead of bar gold from the Bank, which is one of the conditions of the change to be made. It is intended under the enactments of Mr. Lowe's new Coinage Bill, that in future all gold coins issued from the Mint shall approach more closely to the actual legal standard weight than they have hitherto done. This will prove, or we are crank shaft. The engine had a stroke of much mistaken, a costly error. From the 10in., from which we have a piston speed of inevitable variation in the density of standard AVING described the usual arrangement 225-0ft. per minute. The load was raised at gold it is very difficult to produce large quanof engines adopted in machinery of this the rate of 60ft. per minute with a 3-inch tities of sovereigns or half-sovereigns of kind we proceed to briefly describe the rope or lin. diameter. This data gives us uniform individual weight. There must be method by which the goods are hoisted and 2,800lb. raised 60ft. in one minute, or diversity in this respect unless the cost of transferred to or from the hold. We have 168,000lb. 1ft. in the same time; thus this coining be multiplied tenfold at least. At already remarked that, although the engine engine gave a trifle over 5 indicated horse present the law permits of a latitude of lifts, it does not directly lower the weight. power in actual work done without taking any limited extent over and under the theoretical The rope from the barrel is taken to a block friction or other source of loss into account. standard, and this covers the fallibility of or a wheel rigged between the masts directly Now the consumption of coal whilst per- workmanship, whilst it minimises the cost of over the hold. If, as is frequently the case, forming this work, as stated above, averaged minting operations. Closer working to the stanthe winch is hoisting by means of the bitt 2.75cwt. for 7 hours, or 8.46lb. per horse power dard point will, on the contrary, give immense ends as well as by the barrel, and from all the per hour on actual work done; but if we con- trouble to her Majesty's coiners, and maxihatches at once, there is a block or a wheel pro-sider the realised work was 60 per cent. of the mise the expenses of the coining establishvided for each rope; it is, however, sufficient total, we shall be judging very well of the en-ment. If all coins were issued of the exact for our purpose to describe the working of gine, and this will take down the actual con- standard weight they would not so remain one, say the main hatch. The most conve- sumption to 5 10lb on the whole work. The when in circulation for a single week, and as nient of the vessel's yards is so braced boiler was circular, about 5ft. long, 4ft. diameter, none were overweight when put into circu round as to bring its outer extremity directly and having a circular fire tube provided with |lation, as they are at present, all would fall money. The engraver to whom the merit of the designs and the engraving of the die matrices is due is Mr. Leonard C. Wyon, a gentleman whose name is well known in the region of numismatic art, and whose fame will not suffer diminution by this last exertion of his professional ability. HOISTING MACHINERY ON BOARD plicity 4.5 to 1, gave 135 revolutions of the H SHIP.-No. 2. and tear. below the standard when exposed to wear fore have a claim to notice; but they are not even the "Captain." THE PRESENT STATE OF THE TURRET turret-cruisers worthy of the name-the "Monarch" FOR In the "Monarch" the turret guns are carried high above water, the internal accommodation is ample and good, and there is an unbroken upper deck for working the sails, whereas in the "Captain" the guns are comparatively low, the accommodation is not so good, and the sails have to be worked on a comparatively narrow hurricane-deck, which stretches from the poop to the forecastle, and on which the boats, &c., are stowed. The "Monarch" being higher out of water is, of course, more easily hit than the "Captain;" but, on the other hand, the "Captain Passing these vessels by we next come to two cannot bring her guns to bear upon an enemy in a sea-way with the same certainty as the "Monand the "Captain." Both these vessels are fully arch," and the low-decked ship is much more rigged and equipped for sailing besides being sup- liable to injury from plunging fire. On the whole, plied with full steam power. Both have good therefore, as we said before, the higher freeboard protective armour on the sides and turrets, the seems preferable, especially as it is now proved Captain" having a slight advantage in her broad- beyond doubt that it can be obtained in association side protection. Both carry four of the heaviest guns with equal steadiness to that obtained in low freewe at present possess (25-ton 600-pounders) and board ships-a point which was once regarded by can fight them readily; but in both the horizontal Captain Coles and his friends as incapable of being range of these guns is limited by means of fore-reached in ships like the "Monarch." castles and the supports of the lower masts, as well as by other obstructions. Neither vessel possesses the all-round fire of the turret guns which constitutes one of the greatest possible advantages of the system; and neither can fire those guns directly ahead or directly astern, so that fighting "end-on" would be impossible if these were the only protected guns carried. In the "Monarch" this need is supplied by means of lighter guns mounted in armoured batteries at the bow and stern; but in in consequence she is the only ironclad of Captain" no such provision is made, and recent design in our navy which is incapable of fighting end-on when required. It is not a little remarkable that this should be so, especially when it is remembered that Captain Coles formerly laid such stress upon the importance of having an allround fire, and that our recent broadside ships are actually possessed of the power of commanding every point in the horizon by guns placed behind armour. the " NOR more than ten years the turret question has been before the public, and has been made the subject of long and loud discussions. As time has passed on, and experience has become enlarged, a more moderate tone has naturally become prevalent in the arguments advanced for and against the new system, but still there is ground for debate. Enthusiastic advocates of turrets do not now, as they did a few years ago, limit the weight of broadside guns to five or six tons, for they are confronted by the success that has attended the working of the 18-ton guns in the "Hercules" broadsides; nor, on the other hand, do we now have much of some of the arguments once thought conclusive against the turret system. The trials which have taken place in actual ships have, in fact, confirmed the belief which most impartial observers held from the first, viz., that both systems have their advantages and disadvantages, but that on the whole the turret system is preferable for working very heavy guns. General agreement on points such as these do not, of course, settle the dispute; and it leaves quite untouched the now important question of the relative merits of rival types of turret ships. During the last four or five years we The "Monarch" and the "Captain" are, as we have heard almost as much said on the latter said, both turret-cruisers, but they are not at all alike point as on the comparative value of broadside notwithstanding. The "Monarch" was built from and turret guns, and quite recently the competitive a design prepared by Mr. Reed, in accordance with trials of the "Monarch" and " Captain" have given directions given by the Board of Admiralty; the it peculiar force and interest. On the whole, there-"Captain" was designed by the Messrs. Laird fore, there appears little doubt that a brief resume of the present state of the turret question will be welcome to our readers, and to this we at once proceed. under the direction of Captain Coles, to whom the Admiralty had given carte blanche for the purpose of demonstrating his views of what a sea-going turret-ship should be. The "Monarch" belongs Nearly all naval officers and naval architects to the high-freeboard class, the "Captain" to the agroe in the opinion that the turret system stands low-freeboard. The upper deck of the former unrivalled for unmasted and unrigged ironclads. ship is 14ft., and her turret ports are 16ft. above In ships of this class the system was first tried; water; in the "Captain" the upper deck is only in ships of this class the system has received its 6ft., and the turret ports are only 8ft. above water. latest development. Of course, we do not mean This is the most important difference, and greatly for a moment to compare the coast-defence ships influences the fighting capabilities of the two designed by Captain Coles in 1862 with the power- vessels. They have, it is true, proved almost ful breastwork monitors of the "Thunderer" class equally steady and easy in their rolling motions, designed by Mr. Reed, in 1869-70; but these but the greater height of her guns above water vessels have the one feature in common to which makes it possible for the "Monarch" to tight we have alluded, although differing so much in when it would be hopeless to attempt anything of other respects and constructed at an interval of the kind in the "Captain." We are not speaking time which seems very great in these days of rapid at random in making this assertion; the probatransitions. To build the "Royal Sovereign" bility of such a difference existing was evident without anything worthy of the name of masts and from the first, and the recent cruise has placed sails was natural enough, for she was a coast-it beyond doubt. In not very heavy weather the defence ship; but to build the "Thunderer" class "Captain's" low upper deck was washed by the and to depend upon steam alone for propulsion in ships intended to be capable of going to sea when occasion required, was a very different matter. The latter step was quite a novelty in our naval construction, and it met with great opposition, as our readers will no doubt remember; but it has been the means of adding to our navy three of the most formidable engines of war yet constructed, and therefore need not be regretted. By giving up masts and sails all hindrances to the all-round fire of the turret guns have been removed, and the vessels will not be hampered or endangered in action, while they will always be ready to fight, and, at the same time, by giving them an extremely large coal supply-about 1,600 or 1,700 tons-the ships will be made capable of proceeding to any port in Europe, or of crossing the Atlantic in case of need. In armour and armament they are far superior to all existing ironclads, and in their construction have received all the latest improvements both as regards hull and machinery. The question between high and low freeboard Between these earliest and latest specimens of has been much discussed during the last three or our turret ships, very different types have been four years, and great interest consequently attended constructed for or added to our navy. First of all the trials of these representative ships. From came the "Birkenhead Rams," which owe their their performances it seems clear that the "Capfame more to the circumstances connected with tain " has too low a freeboard to secure complete their purchase than to any intrinsic merits. They fighting efficiency in a sea-way, and on this ac were our earliest rigged turret-ships, and there- count the "Monarch" type appears preferable to sea repeatedly; and on one of the roughest It must not be supposed from these remarks that there is a necessary connection between low freeboard and a low port in turret ships, and as an example of the association of low freeboard with a great height of port we may again refer to Mr. Reed's breast work monitors of the "Thunderer" class. In them the upper deck is only 44ft. above water-that is to say, about 14ft. lower than the "Captain's" deck, and nearly 10ft. lower than the "Monarch's;" yet the turret ports are to 6ft. higher than the "Captain's" ports, and 134ft. or 14ft. above water-that is, are from 5ft. only about 2ft. lower than the "Monarch's." This result is obtained, we need hardly say, by means of the now well-known breast work arrangement, and it gives a height of port which will obviously ensure freedom from shipping water at the ports when fighting in heavy weather at sea, when the 66 Captain's guns would probably be silenced. The Thunderer's" low deck is, of course, rather more liable to injury from plunging fire than the "Captain's," but it is very much more efficiently protected, having iron plating 2in. and 3in. thick upon it, instead of plating half that thickness, such as is fitted in the "Captain." It is also noteworthy that the "Thunderer's" breastwork deck corresponds in many respects to the "Captain's " upper deck, for on it are found the principal hatchways, the junctions of the turrets with the deck. and the commencement of the unprotected portions of the funnels, ventilating shafts, &c., all of which are about twice as high above water in the "Thunderer" as they are in the "Captain." For both these reasons-the stronger deck protection and greater height of the openings into the interior above water-there is much less danger of the entry of water into the interior of the "Thunderer" through damages received in action than there is of a similar accident in the "Captain," and still less than there is in an American monitor. All these facts, when taken in connection with the superior armour and armament of the now monitors, make their construction a very important event in our naval history. The breast work-monitor system is also well adapted for coast defence vessels, and has been applied in their construction during the last few years. In fact, the first breast work monitor ever built was the "Cerberus," a vessel intended for the defence of Melbourne, and just equipped for her voyage out to that port. Since her design two other vessels of the class have been built for the defence of Bombay, and one very powerful monitor, the "Glatton," has been constructed for our own navy. In addition to these vessels the system has been applied, with some modifications, to the turret-ram" Rupert," which was commenced at Chatham last year. This brief sketch will suffice to indicate the present position of the turret question in our navy. It has been applied mainly to unrigged, unmasted vessels, and in them is best applied in association with the breast work monitor system. The difficulty met with in securing an extended and uninterrupted range of fire for turret guns in rigged cruising ships has hitherto prevented the extensive construction of such vessels, and until some better plan is devised, or applied, it does not seem probable that many more turret cruisers will be built. Mr. Reed, it is true, speaks (in "Our Ironclad Ships ") of a plan which he has prepared for giving all-round fire to rigged turret ships, and thinks vessels built on this plan would be far superior to any existing vessels. He is not likely to have made this statement without a thorough investigation of the problem, and we trust that ere long his ideas may receive a practical development. NOTES BY QUIDNUNC. make way for them to pass. If the General Omni- T Exhibitions, which are to commence in 1871, to the go construct venivrays, whether such wheels above referred to, and a very heavy expenditure HE buildings for the annual International are to be, we learn, of a permanent character, and are to occupy two pieces of waste land of about 200ft. wide, between the Horticultural Gardens and the Albert and the Exhibition Roads, South Kensington. There will be two main buildings, each 1,100ft. long, and each with two floors. They will communicate with the conservatory of the Horticultural Gardens, and through it with the new Albert Hall of Arts, by covered approaches. At the opposite, or southern end, they will communicate with the permanent portion of the Exhibition building of 1862. The buildings will be connected by covered ways with the South Kensington Museum, and also with the station of the Metropolitan District Railway in that locality. The ground floors will consist of a series of chambers, and will be devoted to the exhibition of textile fabrics, and other manufactures, machinery, and tools. The upper stories will be a repetition, on a reduced scale, of the picture gallery of the Exhibition of 1862. These will be lighted by single centre-ridge glass roofs. The floors will be on Fox and Barret's fire-proof principle, of rolled iron girders, filled in with ten inches of concrete, and tiled for the floors. The buildings, which have been designed by Lieut.Colonel Scott, R.E., will be in the Decorated Italian style, and of hard red Fareham bricks; the mouldings, cornices, columns, and courses, in buff-coloured terra cotta. They are estimated to contain altogether, at one time, 50,000 persons. have flanges or not, it seems but little likely that RAILWAY SAVINGS BANKS. of the A very interesting meeting has just been held at Ashford, in the National School Room, of the officers and workpeople of the South-Eastern Railway Company, to receive a report concerning, and to consider the advantages resulting from, the Provident Savings Bank connected with the company. A special train conveyed Sir Edward Watkin, the chairman, a party of directors, and the chief officers of the company, with a large body of workmen from Tunbridge and other parts of the line. An interesting address was delivered by Sir Edward Watkin, who may be considered the parent of the institution, upon Education and Savings Banks, in which he gave numerous interesting particulars respecting the success bank, which had been established about fifteen months since, and also concerning the Savings Bank connected with the Manchester, Sheffield, and Lincolnshire Railway, which he (Sir Edward) The advocates of reciprocity in the matter of had been instrumental in establishing about ten international tariffs have certainly some notable years since. In the South-Eastern Company's arguments, whether exceptional or not, supplied to Savings Bank in the course of fifteen months them by circumstances and illustrations, becoming there had been 3,078 deposits made, amountknown from time to time. We have before us a ing to £4,813, of which 175 had been in sums copy of the printed circular of a London firm, under 1s., 1,965 under 5s., 338 under 10s., posted from Belgium, and extensively distributed in 247 under £1, 135 under £2, 49 under £5, and London. The circular bears the Royal Arms (of 119 £5 and upwards. In the case of the ManEngland), which the firm is entitled to use by chester, Sheffield, and Lincolnshire Railway Savspecial warrants. It is not the most, or the worst, ings Bank, with its longer life, 25,000 deposits that the Belgian Exchequer receives all the money had been made, and, of £32,000 deposited of workthat is taken for postage, and that our establish- ing boys' and working men's money, there was ment in St. Martin's-le-Grand provides the brigade £16,350 now in the bank. Some very touching of letter carriers who deliver the circulars free incidents were narrated by Sir Edward of the gratis all over London; but the circulars are personal and domestic comforts that had been printed on Belgian-made paper, sold by Belgian secured, and of the calamities that had been stationers, with type cut and cast by Belgian type- averted, by the savings of boys and men. Interestfounders; they are set up by Belgian compositors, ing addresses were delivered by Mr. Eborall, the thrown off by Belgian pressmen, and folded by general manager, and several of the employe and Belgian grisettes. There is surely a screw loose officers. Mr. Shaw, the secretary of the company, somewhere in such things being so. as a depositor in the South-Eastern Company's Savings Bank, was rather proud than otherwise in being able to state that the first watch he had ever purchased had been with the money deposited, not in theirs, but in the only other railway company's savings bank that he knew of. He heartily congratulated the candidates who had obtained prizes at the Society of Arts examination. The earnest appeals to self-denial and the exercise of provident habits made by the chairman and other speakers were very cordially received, and the delusion formerly entertained that the knowledge that workmen were saving money and depositing in the savings bank, would keep down wages, appeared to be very thoroughly dissipated. It is much to be desired that the example of the Manchester, Sheffield, and Lincolnshire, and the South-Eastern Railway Companies, and of Sir Edward Watkin, as their chairman, may be followed extensively by other companies and boards of directors, in the establishment of such excellent institutions. The bill for another subway under the Thames, from the City to the Borough, may now be said to have passed both Houses of Parliament unopposed. It is already through the Commons, and on Tuesday passed through Lord Redesdale's committee in the House of Lords. The new subway, which will be much longer than that already made between Tower-hill and Tooley-street, will be double, and about a foot more in diameter, which will admit of omnibuses which will be all in roominess that can reasonably be desired. Although the Tower subway has never as yet been announced as open, it is so successful that it is already proposed to double the line, by driving another tube through the London clay alongside of that already made, The experience that has been acquired in getting the first subway into successful working order, which it now is, will be of great value to the new project. The last stoppage of the traffic of the Tower subway was caused by important changes in the mode of working, and in the provision, by Mr. Barlow, the engineer, of new and improved safety clips to the lifts. The carriage is now THE METROPOLITAN DISTRICT RAILWAY. hauled by an endless rope, passing round the drums at each end of the subway, and not by coiling the slack at each end as before. The new plan is found to work admirably. on Tuesday last, have, we learn, determined HE directors of this company, at a meeting held The site they have fixed upon is but little inferior for traffic purposes to the extension they sought for, as may be inferred from the short distance for construction will be saved. From the present terminus at Blackfriars, the line will proceed under Queen Victoria-street to the proposed terminus. It will stop short just at the point where the construction of the line further eastwards, either to the South-Eastern Cannon-street Station, or further on still to King William-street, according to the authorised route, would have involved the company in fabulous costs for the purchase of the valuable property on the south side of Cannonstreet, and for compensation. The works will be commenced forthwith, and it is hoped that the station will be opened for public traffic, with a series of trains every three minutes, in the early part of next year. NOTES ON RECENT DISCOVERIES IN SOLID MATTERS IN THE AIR OF FACTORIES, &c.— THE The Sheffield CAUSE OF LOSS IN THE MANUFACTURE OF SODA -SOLUBILITY OF CLAY IN DISTILLED WATER. HE air of various industrial establishments has been made the subject of a special study by Dr. Sigerson, of Dublin, who has contributed an interesting paper to the proceedings of the Royal Irish Academy. Although a great deal has been written on the evil effects produced by the solid matters floating in the air of factories and work rooms, it has not been sufficient, and in all probability never will be sufficient, to induce people to take the simplest means of protecting themselves from these matters. grinders object to magnetic masks, and masons refuse to wear a respirator, although they have of late years pretty generally availed themselves of Nature's own air filter, the moustache. In almost all cases working men in doors object to free ventilation, a nervous dread of draughts, indeed, being common to our whole community. Thus necessarily the air of factories becomes loaded with matters volatilized by heat and light particles dislodged and set in motion by the forces employed. For the presence of some of the former in recognisable quantities we certainly were not prepared, but we have Dr. Sigerson's word for the fact, supported by Dr. Sullivan, that antimony is actually present in the air of printing offices. That it should be present in the atmosphere of type foundries is reasonable enough; but whether to an injurious extent, a little inquiry would quickly decide. We do not remember that type founders are the subjects of any special affection due to the inhalation of vapour of antimony, and they would be just as likely to suffer from the action of lead. amount of antimony in the air of a printing office must be infinitesimally small, and it is inconceivable that any harm can be done by it. In the air of an iron foundry a very curious discovery was made. Microscopic particles of iron were found, which on examination proved to be hollow spheres, the excessively attenuated film of metal forming the shell being quite translucid. These must have been formed by the volatilization of the metal in the furnace, and offer a curious study to the physicist. It would seem The that all vapours on condensing form hollow spheres. Carbon and ash were of course found in factory cotton and linen fibres were found, as the same atmosphere. In the air of a shirt they no doubt would be in every draper's shop. It is not at all surprising to read that starch granules are to be discovered in the atmosphere of a corn mill, nor that dust of a very obnoxious character abounds in scutching mills, especially if means, easy to command, are not provided for getting rid of it. The air of a hairdresser's establishment and a stable contain a quantity of hair and also cuticle scales, the latter, we suppose, being particularly abundant where brushing is effected by machinery, or where the curry-comb is vigorously employed. Tobacco smoke, as everybody as to the site of their City Station, and we suppose The numerous street tramway bills continue to it may be added, the terminus, of their line. This, occupy the attention of Parliament. A number in accordance with the recommendation of Mr. of bills have been passed by the House of Com- John Fowler, C.E., their engineer-in-chief, is to be mons, but they have all to go through the ordeal at the junction of Queen Victoria-street with of the Lords, and that, after the select committee Cannon-street, which will not be crossed. The of their Lordships have come to a determination entrance to the station will be on the south side respecting the Government Tramways Bill. This of Cannon-street, and at a distance of only about bill has been under consideration in committee for 100 yards from the Mansion House, of which it several days, but has not yet been disposed of. On will be in sight. The station will be about the Tuesday last, the committee sat and adjourned with- same distance-100 yards- from the Cannon-street out fixing a day for resuming the inquiry. It is Station of the South-Eastern Railway. The comrather to be feared that the course the Legis-pany will still have to mourn over the enormous knew before, contains globules of nicotine, which lature is pursuing in relation to tramways will costs they have incurred in their attempt to get an fully account for the discomfort it produces in summarily stop their extension. As the Tramways extension to the Mansion House, but they may some people who do not smoke, and ought smokers more tolerant to those Bill now stands, the only exclusive privileges that be congratulated upon having come to a wise to make The air of a tramway companies are to enjoy are, the use of decision, in accepting the circumstances forced who object to the practice. flanged wheels, and that other vehicles are to upon them and making the best of them.dissecting room was made the subject of a |