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great explosion takes place. Disc papier draulic lifts, which are now being erected. mâché wads, weighing 180z., and fitting the At the present moment, the Metropolitan, the bore, are used. The experiments on the Midland, the London, Chatham, and Dover,

occasion referred to were instituted with the and the Great Western Railways have direct MECHANICS MAGAZINE.

view of ascertaining the suitable charge for communication with the depôt. The pasthe gun, and the difference of range between senger trains of the Metropolitan run through

shells of 310lb. weight, having parallel versus it every two minutes, and the Great Western LONDON: FRIDAY, NOVEMBER 27, 1868.

taper ends, and hollow shot of 2491b., having Company have an extensive receiving store taper ends.

The elevation was 10deg for goods there.

throughout, and the following results were The building itself is admirably laid out THE WHITWORTH GUN AT SHOE

reported in the “ Standard" at the time : for its intended purpose, and offers every BURYNESS.

facility to the public. The Corporation of Time of Range Flight

Londou obtained an Act for erecting market briefly, the advent of a new Whitworth Projectile.

buildings on the site of Smithfield in 1860,

Right. gun at Shoeburyness, and from which great

and in the following year they procured one things were expected. Nor has expectation

yds.

giving them power to abolish Newgate been doomed to disappointmentin this respect, Common

Market. The business was confided to the

parallel rear for with it the longest range on record has

Markets Improvement Committee, and a been obtained. The piece of ordnance in

design was prepared by Mr. Horace Jones, question is a 9-inch steel-rifled 310-pounder

the City architect. Their parliamentary

Ditto gun, weighing 14 tons 8cwt., breech prepon

powers enabled the Corporation to raise à derance, 61cwt.; length of bore, 140.0ốin. ;

a sum of £235,000 for the purchase of proover all, 163.80in. ; calibre, major axis,

perty, and £200,000 for the erection of the 9.025in. ; minor axis, 8.250in.; rifling Whit

buildings. The Markets Improvement Comworth's hexagonal, spiral uniform, one turn Hollow Shot taper

mittee, having obtained estimates from in 171in. Vent through the cascable in pro

several builders, concluded a contract with longation of centre of axis, the hole being

Messrs. Browne and Robinson at a sum covered with a metal tube-catcher for naval Common shell,taper

within the estimated amount of £200,000. service. The gun is constructed on the built

The ceremony of laying the first stone of the up system, the inner tube being of Firth's

market itself was performed on the 5th of steel, the same as the Woolwich

guns.
This

June, 1867, when a corner stone weighing is covered by a second steel tube, over the

The experiments which took place on

five tons was placed by Mr. Lowman Taylor, rear portion of which is a steel jacket. Over Friday and Saturday last, gave some of the the chairman of the committee. It was not, this again are two jackets of Whitworth most extraordinary results for range ever central area was given up to the contractors.

till the 2nd of March last that the metal, or steel, compressed by hydraulic pres- known. sure. This metal can be made of any degree 10,300yds., with à 2501b. shot, a 5016. The market is a parallelogram, 631ft. in of hardnsss or ductibility, and Mr. Whitworth powder charge, and a maximum elevation of length by 246ft. in width, and covers 31 acres. wrought iron, and his steel metal, as used for 33deg. On Saturday, this gun beat even its It is not a particularly imposing structure,

previous performance, and with 33deg. 5min. but in its construction the architect had to ordnance, are respectively as 30, 100, and 250. elevation, and a 50lb. charge, threw a 310lb. have stern regard to utility as regards most Some preliminary trials of this gun were shell 11,127yds. to the first graze, being be called Italian, though it resembles more made by the Ordnance Select Committee in about 1,000yds. further than any projectile | the renaissance architecture of France. As the middle of September last, when, after

was ever hurled by any other gun. We shall firing seven rounds, it was tested by Mr. return to the details of these interesting structure in detail in our next and following

we propose to illustrate and describe this Whitworth's machines (which gauge to the trials in our next; in the meantime, we may impressions, we need not now enter upon ten-thousandth part of an inch) for detection congratulate Mr. Whitworth upon having further particulars. Few public buildings of the slightest enlargement of the bore, or obtained ranges which we believe to be un- have been erected in so short a time as has ing that the first sign of the yielding of the approached by any other gun in the world.

this admirable market. It was only ou the metal marks the commencement of the destruc

5th of June, 1867, that the first stone was tion of the gun, and these delicate testings THE NEW METROPOLITAN MEAT of land have been covered with a building

laid, since which time three acres and a-half enable the immediate determination of the maximum charge to which the gun could be

AND POULTRY MARKET. which is worthy to stand by the other great exposed without injury. The measurements TP to the present time, the reproach of works now being carried on by the Corporashowed a set of one two-thousandth of an inch

The at the extreme rear end of the chamber; of one of public market accommodation has clung to Holborn Viaduct are the foremost. seven-thousandth at the front of the chamber, the City of London. This reproach has now building will be actually opened to the public and thence to the muzzle there was absolutely been removed, for on Tuesday last the new

on Tuesday next, on and after which day no difference before and after the firing. The Metropolitan 'Meat and Poultry Market, Newgate Market will be abolished. exceedingly minute difference shown may be which has been built by the Corporation on readily accounted for by the wear even of the the site of the old Smithfield Market, was instrument or of the face of the bore, or by formally opened by the Lord Mayor, who

ELECTRIC RAILWAY SIGNALS. compression of the mass of metal. In fact, proceeded in state to the site, and "inaugu. there was no real or actual distension of the rated" the new street to the Holborn Valley of action of railway signals must albore.

as well as the market itself. For seven ways be welcomed by the travelling public, Mr. Whitworth's projectiles are entirely of centuries Smithfield had continued to be the and, indeed, by the world at large, as an iron, hexagonal in form, and made spiral to market for live stock, until within recent advance in rendering travelling more safe. follow the rifling of the gun, having a years—in 1852—an Act of Parliament Junction and station signals have of late been windage over the major axis of 0·065in., and abolished the nuisance, and transferred the wonderfully improved upon by the “locking over the minor axis of 0.070in.

cattle market operations to Copenhagen- apparatus," rendering points and signals deIn the preliminary trials the projectiles were fields. This market was constructed by the pendent upon each other. These are all steps of three kinds, viz. :-Common shells having Corporation of London, and now they have in the right direction, but with regard to parallel rears, and weighing 290ļlb. empty; added vastly to their former good services by distant signals there is still room for imlength 31.6in.; diameter, major axis, 8.96in. the erection of a dead meat market upon the provement. We do not mean to such signals minor axis, 8:18in.; capacity for bursting waste of Smithfield. This, of course, will generally, but to a large number in particular powder, 18lb. Common shell with taper lead to the closing of Newgate Market, a cases. To distant signals in curves, cuttings, rears, 285lb. empty; 31.6in. long; in dia- step which no one who has had to pass down or in situations invisible from the signal box, meter, 8.96in. by 8-18in.; bursting charge ca- Newgate-street and its neighbourhood during allusion is specially made. With regard to pacity, 181b. And hollow shot with taper rears, market hours will regret. The arrangements distant signals generally, it is usually con2491b. weight; 24.7in. long; in diameter, of the new market are complete in every sidered advisable to have them at such a good 8.96in. by 8.18in. Mr. Whitworth's car- respect; various lines of railway converge to distance - 800, 1,000 yards or - from tridges are specially arranged so that the it, beneath the surface, as a central point, the signal box, so as to be easily manageable powder may be ignited well to the front and by which the gupplies of meat will and easily seen; but of course it is impossible first. A thin copper tube perforated with a arrive. In fact, the basement of the market in many cases to fulfil both conditions; either number of small holes for half its length, is is a through railway station, from which the distance must be shortened, in order to passed through the centre of the charge. there will be communication not only with all keep the signal in sight, or the distance mainInto this at one end is inserted a small parts of the country but with all the tained and the signal left out of sight. In funnel-shaped primer cartridge, containing suburban lines. It is intended that, when the latter case, it would be impossible for the 120 grains of powder, the object of which is the meat arriving by rail reaches the dep t signalman to know whether his signal acted to ignite the charge of the gun rapidly, and underneath the market, it shall be raised to properly. And in the former the distance to begin to move the projectile before the the level of the floorway by powerful hy-I would be so reduced as probably to prevent

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a train from pulling up a sufficient distance is an important element in the safety of a distant signal. With such an arrangement, from the platform. Any invention or plan, signals. "We may possess the expensive a signal can be placed at its maximum distherefore, to enable the distant signal to be arrangement of repeater, that will inform the tance, and the signalman will have an indimaintained at its maximum distance, and at signalman that the distant semaphore arm is cator in face of him that will give him a faiththe same time to give the signalman an to" danger," but what use would that be if ful register by day and by night of the state accurate knowledge of the state of his signal, the light were out. The repeater, however of signal. cannot but be acknowledged as an important useful it may be in the daytime, utterly fails By a reference to figs. 1, 2, and 3, our advance in the direction of safety. at night.

readers will perceive the instrument we speak There are many circumstances which may For many years there has been working on of. (It is equally easy to make the instruprevent a distant signal being seen-curves, the South-Western line a small electric re- ment a semaphore " instead of a "disc" inequalities of the country, intervening peater at the Surbiton station. The up side signal). In fig. 2 the disc mounted on a long bridges, buildings, or other erections, stop- there consists of a sharp curve in a cutting, upright rod D pivoted at the bottom carries ping the view. Again, in many districts, fogs and the distant signal is quite out of sight. at its lower extremity a soft iron armature A; prevail to so great an extent throughout the From the signal itself proceeds a wire along behind is an electro-magnet E E-one end in year that a signal at any distance could not the telegraph poles to the signal box, where connection with the line wire to the contact be perceptible. There are innumerable in- it is attached to a miniature signal worked arrangement on the semaphore arm, the other stances where such things occur, and it is an by electricity. In the box is a battery connected end through a battery to earth ; the spring important element of safety that the signal through the miniature” along the wire to the S maintains the disc in its normal position. should always be visible to the signalman, in distant signal. On the signal is a contact Immediately the signalman moves his lever, order that he may know when he pulls the arrangement, which, when the signal is the distant disc is turned ; the arrangement lever that the signal obeys. If it were not so, brought by the signalman to "danger," makes on it completes an electric contact between how little safety there would be in travelling ! contact, and completes the electric circuit, the line and the earth establishing an electric The importance of this has been acknowledged the “miniature” signal immediately shows circuit, the battery actuates the electro-mag. as so great that where it is absolutely neces- a similar signal. In this case, the peculiar net, the armature is attracted, and the disc is sary to have a distant signal out of sight, it form is that of the “disc.” As soon as the held over so long as the circuit is maintained. is usual to placea second, intermediate between signalman pulls his lever and throws the dis- When the signal is reversed, the circuit is the box and the distant signal, worked by tant disc to “ danger," the electric disc in front broken, the electro-magnet loses its magthe distant and visible from the box. They of him immediately is turned, and he is at once netism, the armature is no longer attracted; are usually termed * repeating signals,” but satisfied that his signal is all right. The ex- the spring S, consequently, forces the disc whatever elements there are in the distant periment answered so satisfactorily that the back to its normal position. signal that are liable to fail, such as the wire adoption of the electric “ repeater” became | Fig. 1 shows an ordinary view of the recatching, &c., there must also be in the “re- more general on the South-Western line, and peater, showing the disc, and the tell-tale in peater," so that it is quite possible that a dis- gradually became extended to other lines. front with the words LIGHT IN. Figs. 2 and 3 tant signal may and the repeater may not Its original conception and carrying out is will enable our readers to understand this work. A serious consideration with regard to entirely due to its inventor, Mr. W. H. latter arrangement, which is, we believe, printhese repeaters is the large increase in the Preece, of the South-Western Railway. It cipally the invention of Mr. Warwick, of expense necessitated by doubling the signals. is, in reality, an adaptation of his railway Derby. CC is an electro-magnet of a similar It must be acknowledged that if it is neces- electric signals for the block system. It was, ' construction to the one we have already desary that the signal should be visible during however, found that more could be made of scribed ; in front of it is a rod having a hamthe day, it must be equally necessary that it this, and under its most recent form it con mer II at its lower free extremity, the upper be visible during the night. This cannot be tains not only a correct repetition of the state 'end being attached to a loose spring, and done by the same repeater, which would only of the distant signal, but also of the condi- having a soft iron armature a, a short way show its own light; but here, again, we have : tion of its lamp, whether it be alight or not. from that extremity, and exactly in front of the the double risk of the light going out. This , We have, therefore, the great desideratum for poles of the electro-magnet ; a spring keeps this

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rod at some distance from the electro-magnet. ders, iron masts, and miscellaneous details, manipulation which the rivet has to undergo B is a bell placed under the instrument to be such as riding bitts, thrust-bearers, paddle- in being manufactured and put in place. In struck by H. Above the electro-magnet be- beams, &c. These subjects are of minor im- this general view we entirely agree with the tween its poles (fig. 3) is placed a magnetic portance compared with framing, plating, author, but we are not quite satisfied with needle F, carrying on the same axle an indi- decks, &c., but they are nevertheless essential the theoretical view which he has ven in a cator I having on it the words IN, OUT. The to a book of this kind. They are well explained, foot-note. We should mention that it is put electro-magnet is connected one end to a and illustrated. The illustrations of the forward not as a strictly accurate but as a battery to earth, the other end to the line chapter on rudders especially deserves men- not unreasonable solution. He simply finds wire to the distant signal ; but to enable our tion. The next chapter is on the use of steel the resultant of the two strains (the tension readers to understand the complete action, it plates for shipbuilding. This is a difficult and the shearing) on the section, and equates will be necessary to explain the arrangement subject to deal with, because of the many it to the breaking strain of the iron. *This in the lamp itself. Figs. 4, 5, and 6, will different opinions entertained and expressed theory, which holds for the strains on any make this clear. A is a strong cast-iron about it. This chapter is chiefly a record of small particle in the section, cannot, we think, framework. B, a brass tube firmly fixed at the experience and views of men who, evi- be applied to the whole section, because of the C, but free to move at D, its other extremity: dently feeling the desirability of combining unequal distribution of the shearing stress E, a lever centred at F, and in its normal strength with lightness, have endeavoured to over the section of the rivet, while the tension position making contact (fig. 6) with the further that end by the adoption of steel is uniform. The result of this unequal disadjusting screw H; the spiral spring G exer- instead of iron. Its publication, by showing tribution is that the resultant stress on some cises sufficient force on E to keep it in con- the peculiarities of the metal, will tend particles reach the breaking point earlier than tact with H.

towards its use for suitable purposes; and by on others, partial rupture commences, and The line wire is in connection with the pointing out its failings will, we hope, incite the rivet, at a certain moment during the insulated point H, whilst the framework—and, manufacturers to greater efforts to remove shearing, would be so crippled as to snap off consequently, the lever-is in connection with them.

from the effect of the tension alone, without the earth. In the normal position of things, Rivets and rivet work form the subject of allowing the shearing strain to do its proper a circuit is established at the point H, the the next chapter. We should like to dwell share, like (to use a rather exaggerated illucurrent from the battery acts upon the electro- largely on this part of the book, but space stration) the way in which india-rubber bands magnet, attracting the magnetic needle to one will not permit. It is a subject which snap off if only partially cut when under tenof its poles and showing the signal light out. interests the engineer as much as the ship- sion. It would be interesting to compare the As this is the position during the day, the builder, as is evidenced by the number of fractures of some rivets sheared when under handle K is an arrangement for breaking the eminent men who have written and experi- tension with those of rivet iron, for if tearing circuit, and preventing the needless waste of mented upon it. _Among them we have the such as we have suggested takes place, we the battery. At dark, when the lamp is names of Mr. Fairbairn, Sir Charles Fox, should probably then see evidence of it. lighted, the heat from the flame acts upon the Mr. Clark, Mr. Doyne, and Mr. Kirkaldy. Although a great deal of this chapter is applitube B ; this gradually expands, but it being The results of the investigations and experi- cable specially to shipbuilding, it is neverthefixed at one end it expands at its free extre- ments of these gentlemen are brought less the most comprehensive and able treatise mity D, gradually pressing úpon, the end of together, and supplemented by experiments on rivet work in general that has ever been the lever Ě; as the expansion rapidly increases, made at Chatham and Pembroke Dockyards published. The chapter on testing iron and the pressure on E becomes so great that the to clear up points which previous experiments steel, which follows, is very instructive, and opposite end is forced from H, and the cir- had left in doubt. The conclusions drawn by will be welcomed by everybody interested in cuit becomes broken, the electro-magnet is no the gentlemen above mentioned are carefully ironwork-except, perhaps, by the iron manulonger active, and the indicator I falls to the weighed, and where the author does not facturers. position Light in. So long as the lamp burns, entirely concur with them, he bases his Chapters XIX. and XX.--the former on so long the indicator will remain in that posi- opinions on sound principles, and fortifies Lloyd's and the Liverpool rules, and the tion. Now watch the effect of the light going them with experiments, which make his case latter on systems of work-have quite a novel out. The temperature suddenly falls, the tube very clear and convincing. A point to which feature in them. The chapter on Lloyd's and B responds to the change of temperature and we would wish to draw attention is where the the Liverpool rules is chiefly composed of contracts, lessening its pressure on E until it author treats of the shearing of rivets. Mr. comparisons between them, and will have a presses no longer, when the spring G, now no Clark, who has made experiments to deter- special interest for builders of merchant ships. longer opposed, exerts an opposite pressure mine the shearing strength of rivet iron, The chapter on work, while being a full and on E and establishes its contact at H, the mentions the fact that rivets, worked hot, detailed account of the systems adopted on circuit is immediately established, the electro-contract in cooling, and draw the plates the Mersey, the Clyde, the Thames, the Tyne, magnet becomes active, attracts the armature, together, thereby causing friction. From this and in the Royal Dockyards, is constructed causing the hammer to strike the bell, and he infers that the value of the rivet is greater and arranged in such a way as to bring procalling the signalman's immediate attention than the shearing strength of the rivet iron minently into notice the difference which to the indicator, which now faithfully shows by the amount of the friction. Later experi- exists in the practices at the several places. that the light is out. It gives instant warn- ments on riveted work show, however, that We think, with the author, that bringing ing, and time for the lamp to be put right be- the value of rivets falls below that given by these differences into notice may tend towards fore danger can arise. Contrast this with the Mr. Clark for rivet iron, although it includes an uniform system of work, and uniformity in mechanical repeater we have before men- friction also. Mr. Fairbairn, in his “ Useful the rules which regulate the building of iron tioncd, and how favourable the comparison. Information for Engineers," mentions this ships in this country. Since locality can have In usefulness and faithfulness, it is superior; fact about the friction not appearing to help no special bearing on these points, it does in cost, far less. Need we say more?

the rivets, but does not attempt to account seem reasonable to hope that the advocates The foregoing description is, it is to be for it. The author explains it by saying that of each system may see advantage to be gained hoped, perfectly clear to our readers, and the the friction does help the rivet, but that the by copying something from the others, and instrument is brought forwird as a most use- rivet is much weakened by the working and thus gradually approach a common practice. ful invention-one calculated to lessen the risk by contraction during cooling. To show the The concluding chapter is on armour plating. of travelling, and lessen the danger of acci- extent of this, he takes Mr. Clark's values for It describes the method adopted for fitting dent to life and property. Of its perfect suc- the shearing strength of rivet iron; experi- and bending armour plates, and the different cess, the number that are now being fixed will ments at Chatham Dockyard supply the shear- ways of securing them; and includes a paper, give ampie proof, the new Brighton branch ing strength of rivets in place (including read by the author, before the Institution of from Peckham to Sutton having every signal friction), and some experiments made at Naval Architects, on the "Warrior,” “Lord fitted with these repeaters.

Pembroke (which are described in the book) Warder,” and “ Hercules " targets. Lloyd's give the amount of the friction; and by and the Liverpool rules form an appropriate

deducting the difference between the appendix, because of the numerous references SHIPBUILDING IN IRON AND

two last from the first, he gets the which must necessarily be made to them in STEEL.

amount which the rivet has been weak- any work on practical iron shipbuilding. TE last week left Mr. Reed's practical ened. To take an example of a three We have now run-somewhat rapidly, perWE

work on shipbuilding at the close of the quarter rivet:-Shearing strength of the haps, but by no means carelessly-over the tenth chapter, and with pleasure we renew rivet iron 19.52 tons for a double shear; broad fields of valuable practical matter our acquaintance with the author at Chap- double shearing force of a three-quarter rivet which Mr. Reed places before us. We would ter XI. This chapter, which is on bulkheads, in place= 18 tons; mean value of the friction willingly have extended our research, but our contains a very clear exposition of the rules caused by a three-quarter rivet = 4.6 tons, limited space precludes this ; in fact, our which should govern their spacing and ar- from which we find that the shearing strength chief difficulty has been to condense and rangement, and of their uses both structurally of the rivet amounts to 13} tons, or about six abbreviate. We have, however, said enough and as a means of safety against foundering. tons less than the double shearing strength of to indicate the high character of the volume, The different methods of forming them ; of the iron from which it was made. The author and to show that an important addition has their connection with the ship's side ; of conjectures in the text that the principal been inade to one department of scientific making them water-tight, and of fitting them cause of this loss of strength in the finished literature. The questions upon which it with water-tight doors and sluice valves, are rivet is the interior stress of the iron due to treats are by no means finite, nor incapable very minutely described. We next reach four the contraction, and he adds that there is of further extension. On the contrary, the chapters which are devoted to topsides, rud probably a further reduction due to the science of shipbuilding is, like inost other

sciences, capable of further development. the cause —or, perhaps, one of the causes-con- metry, and we are glad to see that the author The conception of yesterday becomes the tributing to such a result is the presence of a has produced a volume which is admirably theory of to-day, and speedily merges into superior ore. Our English ore, it is uni- calculated to promote that object. He hathe practice of to-morrow. But, as far as versally admitted, is not of a rich description, divested the subject as much as can be pos the subject has been developed in the direc- and cannot compare with either the magnetic sibly done, consistent with preserving its tion treated of by Mr. Reed, he has fully oxide of Sweden and the northern countries, characteristic features, of all abstruseness informed his readers upon every point. The or with the hæmatites which constitute a and mathematical complexity, and has sucentire volume bears ample testimony to the valuable source of future wealth in our Indian ceeded in rendering it easy of perusal by practical knowledge possessed by the Chief possessions. The volume we have noticed is anyone who has had the commonest rudiments Constructor of the Navy, and his work will arranged upon the paragraph system, which of education. The diagrams are well chosen remain a standard of reference to shipbuilders renders it easy of reference, and affords com- and clearly cut, and the type is all that could so long as true engineering principles and plete information upon all points connected be desired in a work of the kind. practice continue to be applied to naval con- with a subject so inportant.

The condensation of valuable matter, so as struction. The best evidence that can be It may be a somewhat bold statement to to accomplish what may be termed a literary adduced in favour of the practical nature of make, but nevertheless we fully believe and scientific multum in parvo, is one of the the work is that the Lords of the Admiralty Euclid, so far as the translation has come inost difficult tasks ever undertaken by comhave directed that the examinations in prac- down to us, to be virtually obsolete. Does pilers. In the attempt to do too much, they tical iron shipbuilding of candidates for pro- any single one of his readers remember to generally fail in successfully carrying out motion in the royal dockyards will, in the have learned it at school otherwise than by what might otherwise be effected. Mr. main, be based upon Mr. Reed's treatise. rote? We confess we acquired it in no other Humber's latest compilation* embraces the

manner, and being blessed with a very reten- results of nearly everything that has been

tive memory, were considered to have excellent written respecting moments of strain, action NOTICES OF BOOKS.

mathematical proclivities, solely upon the of loads, calculation of areas, and proporN

at our disposal, and also of the energy and truth is that the whole style and diction is so possible to introduce much novelty in a small skill with which we availed ourselves of their tedious, prolix, and complicated as to abso- office companion similar to that under consiresources, in the shape of iron and coal, may lutely disgust the youthful student who re- deration, but, nevertheless, the manner in be attributed the foremost place that we have quires to have some slight incentives to which the diagrams of strains are treated preever occupied as the votaries of Vulcan. At enable him to undertake the arduous task of sents many points of interest and value to the the same time, it must be confessed, that our the acquisition of knowledge. We fully pupil and beginner. They serve the purpose once boasted monopoly no longer exists, and endorse the opinions of the author of the pre- of good examples to be worked out on a larger that other nations have followed our example face to the work before us* upon this point, scale. We should be inclined, ourselves, to in exploring and utilizing the mineral stores at and consider that no real progress towards have omitted the first portion of the book, their command. We have a proof of the fact a comprehension of the subject will ever be relating to moments of rupture, as it is not that our French neighbours can fully appre- arrived at by the youthful and immature in- of immediate practical importance. What an ciate the advantage to be derived from a tellect, until the principles of geometry are engineer requires in working out the details thorough knowledge of the subject and art of taught upon a more modern and more agree- of a girder is not the moment of the strain, metallurgy, in the volume before us.* The able system. The manner in which they but the actual strain itself. In the calculaintroduction includes a complete history of are disseminated through the contents of tion of the latter, the depth of the girder, one steel, and its successful employment by Euclid, renders that book a complete scien- of its most important proportions, is taken different nations, with a description of the tific conundrum to anyone but an advanced into account, whereas it is not included in means employed respectively by them for mathematician, who cares little about consult- the simple moments of the strain. This holds developing its useful qualities. After treating ing it, since, by means of ordinary geometry, good so far as the flanges are concerned, but of the action of sulphur, phosphorus, water, algebra, and other higher branches of the not for the web. The depth of the latter has and limeupon the material, the authorproceeds same order, he is perfectly independent of its uo effect upon the strains brought upon it, to the subject of iron ores and the various fuels theorems and propositions. In addition to provided it be secured from lateral flexure, employed in their smelting. Part the first observing the usual routine of lines, triangles, which can easily be accomplished, in the case introduces us to the theory of steel, including circles, polygons, ratio, and areas, Mr. of a plate girder, by proper angles, tie, or that of the well-known sávan Réaumur, and Wright introduces some new applications of other sectional stiffening irons, and in that of also treats of the quantitative analysis of the art, and endeavours, as far as is possible an open web, by first employing a section of that substance. This is a very important in a subject so hackneyed, to throw a new iron suitable for resisting compressive strains, question, as steel is liable to be intermixed with dress over very old materials. The proper and secondly by interbracing the diagonals many foreign bodies, such as alumina, chrome, way for the beginner to learn plane geometry, themselves, if the web be double. The effect of lime, manganese, and magnesium. These and to profit by his knowledge, is to take a the various positions of a load upon a girder may all be discovered and estimated by the small drawing board, pencil, compasses, and are accurately investigated, and give the action of suitable chemical reagents, com- scale or ruler, and work out the propositions same results as those arrived at by ourselves bined with the ordinary mechanical means before him, carrying on, at the same time, in in our articles upon that subject. We regret usually at command in all laboratories. The his mind the process of reasoning that will to find that the author has not more fully inmetallurgy and working of steel occupy the lead him, in conjunction with the diagram, to vestigated the cases of wrought-iron arches second and third parts of the volume, which thoroughly master the problem he has in hand. and those of curved roofs, which are now so includes an account of the new processes. Either of the two operations may not be suf- much used by engineers in the Metropolitan These the author alludes to as the Chenot, ficient without great labour, but when the and other stations. This is a branch of the Bessemer, Taylor, and Uchatius processes two are carried on simultaneously, there is subject of beams and strains regarding which An interesting reference is made to the little or no doubt but that a complete under- very scantyinformation exists, while the others Damascus blades, so highly prized by oriental standing of the case will be obtained. At are all more or less trite and familiar to pro. warriors, and which, it appears, all the efforts the termination of each of the four books or fessional men. Those who are acquainted of their western brethren, aided by their subdivisions comprising the volume, the author with Mr. Stoney's admirable work on strains greater skill and knowledge, have been unable has added a series of exercises embracing a will at once perceive that Mr. Humber has to imitate. Part the fourth is devoted to the number of questions, calculated to test the trodden in the same path, his object evidently properties and the uses of steel, embracing the proficiency of the student in the contents of being to reproduce in a handy form the majority various forms of files, plates, saws, needles, the previous pages. There is no doubt but of the instances and examples afforded in that and wires. A valuable appendix brings this that the greatest amount of attention is de- larger and more comprehensive volume, and useful volume to a close. It is an extract from manded by the third "book,” which treats of so far he has succeeded. Short rules are given the report upon Bessemer steel by Abram ratio and proportion. It is not difficult to per- for the calculation of the proper proportions S. Hewitt, the United States Commissioner. ceive, without any great mental exertion, the of bolts, rivets, and other usual methods of From this report it appears that Sweden pro- ratios of dissimilar lines, but it requires a forming constructive connections, and a deduces a superior description of metal to our higher exercise of the intellect to follow the scription of the various ways of delineating selves, and is able to turn out a finer kind of proportions of triangles, circles, and irregular the parabola, concludes the contents of the wire. The ore used in that country is the figures, where the comparison is no longer little book. The diagrams and plates are well-known magnetic ore and is represented linear, but superficial. In solid geometry, small but well defined, clear, and explanatory by the chemical formula Fe 04, or, as it is the difficulty would, of course, be still further of the text. It would have been an improvesometimes written, Fe, 0, + Fe 0. A increased, but of this subject we have nothing ment if the type selected had been a little similar superiority over English steel is also to mention at present. One of the first larger, although the heading of each proposiexhibited by that produced in Austria, and studies to which our artizans and working tion being printed in black letters renders *"A Treatise on Steel, comprising its Theory, Metal

men have to apply themselves, if they intend them sufficiently distinct. lurgy, Properties, Practical Working, and Use." By M.H. entering upon technical education, is geo

* "A Handy Book for the Calculation of Straius on C. SANDRIN, jun., Civil Engineer. Translated from the

Girders and Similar Structures, and their Strength; conFrench, with notes, by A. A. FESQUET, Chemist and En # "The Elements of Plane Geometry, for the Use of sisting of Formule and Corresponding Diagrams, with gineer. With an Appendix on the Bessemer and the Martin Schools and Colleges." By RICHARD P. WRIGHT, formerly Numerous Details for Practical Application," &e. By Processes for Manufacturing Steel, from the report of Teacher of Geometrical Drawing in Quenwood College, WILLIAM HUMBER, Assoc. Inst. C.E. Author of "A Pras ABRAM S. Hewitt, United States Commissioner to the Hampshire. With a preface by T. ARCHER HIRST, F.R.S. tical Treatise on Cast and Wrought Iron Bridge ConUniversal Exposition, Paris, 1867. Philadelphia: Henry &c., Professor of Mathematics in University College, struction,". "A Record of the Progress of Modern EnCarey Baird, Industrial Publisher, 406, Walnut-street.

London: Longmans, Green, Reader, and Dyer. gineering," &c. London: Lockwood and Co., 7, Statidner's London: Trubner and Co., 60, Paternoster-row. 1868.

Hall-court. 1868,

London,
1868.

BURE A UOF THE RUSSIAN COMMISSIONER AT THE

PARIS EXHIBITION.

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RUSSIAN TIMBER BUREAU.

graceful modification of the Russian style. The let in Aush with the façia. The key is made also

elevation and plan require no explanation, but to support the piece of round timber which lies E last week illustrated and described the there are some peculiarities of construction which across and keeps down the shingles of the roof, now give another example from the Paris Exhibi- turo are visible to the eye. The rafters appear are in this case squared, and are put together with tion. This in an elegant little bureau, designed for beyond the timbers of the gables, their ends being grooves and ngues, like our flooring boards. the use of the Russian commissioner, by M. Paul turned or carved into grotesque heads, and are held This is also the method adopted by the NorweBenard, of Paris, who has produced an extremely in place by the ornamental keys or pins, which are gians in the construction of their wooden buildings.

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