THE MECHANICS' MAGAZINE. LONDON: FRIDAY, JULY 17, 1868. DYNAMITE. remaining half of the cartridge was then fitted with the detonating cap would effect fired with a capped fuse, a violent detonation its explosion at the proper moment, whilst if being the result. The absence of all danger the shell broke up in the gun, no harm would in case of collision or fire during transport result, as we demonstrated by previous experior storage was then demonstrated in a most ments. The danger attending the use of a marked manner. A small deal box, contain-shell was too great to allow of its adoption by ing about 8lb. of dynamite, was thrown down Mr. Nobel, but he fairly met the point by from the top of a cliff 60ft. or 70ft. high upon filling a tin case with 44lb. of dynamite, and a hard bed of rock below. The concussion firing it behind a piece of curved 3-inch started the joints of the box, but the contents wrought-iron plate, 2ft. high and 3ft. long, remained uninjured and unchanged. The measured round the curve. The plate was test of fire was then applied to a similar box broken into four unequal parts, which were to the last, containing about the same quan-blown considerable distances away. The A brisk wood fire was face of the plate upon which the powder had QUE UR readers are aware that nitro-glycerine tity of dynamite. has never found a friend in us; we have kindled, upon which the box was placed. acted was completely pitted with small holes, always condemned it for its fearfully dan-After a few minutes of anxious watching, the due, as some asserted, to the particles of tin, gerous and uncertain character, even under box quietly wobbled over on one side, a but as we believe to the atoms of stone in the gentle puff of smoke and flame issued from dynamite. This experiment satisfactorily the most favourable circumstances. Only a fortnight since an explosion at a nitro- it for a few seconds, and 8lb. of one of the demonstrated the great velocity which would most violent of modern explosives were be imparted to fragments of shells charged glycerine factory, and another in Belgium, almost noiselessly dissolved into thin air. with this explosive. gave us an opportunity of warning the public The charred and blackened box minus one The next point was to illustrate the against this treacherous compound. We side-that which had been nearest the fire-action of dynamite in blasting the rock. fully admit its resistless energy and its great was removed from the embers, the joints A charge of 12lb. was inserted in a vertical value in this respect in blasting operations, but inasmuch as there do not appear to be being sound and whole. We examined this bore hole 15ft. deep, and 2in. in diameter box of dynamite before it was nailed down tamped with sand. The explosion was any conditions under which it can be handled and placed on the fire, as also the one which indicated by a low subterranean thud and a with safety, we conceive its use ought every-was thrown down the precipice, after the oc- perceptible tremour of the surrounding land, where to be prohibited. Under these circumstances it is with peculiar satisfaction that even at a considerable distance from the blast. The rock showed a series of fissures which we turn to a contemplation of this hitherto sufficiently indicated that an enormous mass uncontrollable agent of destruction in a new had been loosened, and was ready to be form, in which it is comparatively harmless detached by the pick. Had the rock been of and absolutely far safer to handle and transport than gunpowder. Mr. Nobel, after long experimental research, has effected a new combination, in which he has truly tamed the lion and has rendered him innocuous, except under the actual conditions of work. To the new substance Mr. Nobel has given the expressive name of " Dynamite." It is simply a fine gravel saturated with nitro-glycerine. With this interesting composition a series of experiments were carried out at the Merstham Grey-stone Lime Works, near Redhill, Surrey, on Tuesday last. A large party of scientific gentlemen, including engineers, contractors, mining agents, and others interested in blasting operations and in the safe transport of dangerous materials, were conveyed to the scene of operations in a special train. used as an paper cases. Amongst the gentlemen present were Sir Charles Fox, C.E., Professor Noad, Mr. Browne, of Woolwich Arsenal; Messrs. Dierden, Williams, Hitchins, Sharpe, Green, Watson, &c., the representatives of the Great Western Railway, London and NorthWestern Railway, and other lines. The object of the experiments was mainly to illustrate the power of dynamite when explosive agent, and its harmlessness under all other circumstances and conditions. To this end, Mr. Nobel had prepared a number of cartridges of various sizes; they were simply the dynamite in thin To each of them was attached a fuse which burned at the rate of 18in. per minute. On the end of the fuse, which was inserted in the cartridge, was fixed a copper cap primed with a powerful detonating compound. And it is to be remarked here that to this cap is due the development of the explosive energy of the dynamite. A charge of half an ounce of dynamite was first exploded on an oak plank about 6ft. long, 9in. wide, and 2in. thick, and supported at each end. An exceedingly loud and sharp report told that some work had been done, and so it proved, for an examination of the plank showed that the charge had taken effect completely through the board, the under side being rent and splintered. A similar charge was then fired on a balk of fir timber placed flat on the ground. A deep indent was made in the timber, and one side was splintered off. To prove the harmlessness of the dynamite when fired by an ordinary light, Mr. Nobel cut a cartridge in two, and lighted one half in his hand with an ordinary fusee. It burned quietly and quickly, but not rapidly, out. The currence, and we therefore write from our a harder and less friable nature, it would Experiments were now made with the view have offered a greater amount of resistance, of testing the power of the dynamite when and the whole mass would have been blown under conditions of partial and perfect con- out. This was the case at some granite finement. First, about four ounces of dyna- quarries at Stockholm, where an immense mite were placed upon a block of granite mass was detached and thrown down in measuring 3ft. by 2ft. 9in. by 2ft., the dyna- huge blocks. On the present occasion mite being only covered in with a lump of a further charge of 4lb. of dynaclay and a shovelful of gravel. A very loud mite was fired at the same depth as the report followed, and on examining the stone last, with proportionate results. Mr. A. E.. it was found to be traversed by rents and Walton, one of the gentlemen present, and fissures, large masses being easily detached who is constantly engaged in blasting operaby a crowbar. The effect was certainly sur- tions, affirmed that the results greatly exprising, considering the comparatively loose ceeded his expectations, considering the and unconfined condition of the charge. Still comparative smallness of the charge. The more astonishing were the effects of the ex- method of charging in dry ground was next periment which followed. Here, a cylin- illustrated by filling a glass tube with a series drical block of wrought iron, about 12in. of cartridges which were tamped with loose high and 10 in. in diameter, and having a sand and fired. This experiment was repeated 1-inch hole bored through the centre, was with water tamping to illustrate the mode of used. The bore hole was filled-but not operation in wet ground. A striking effect rammed tightly-with dynamite, and fired, was produced, at the suggestion of Sir Charles the party retiring under cover at a very re- Fox, by firing a cartridge in a bucket of water. spectful distance. A report soon followed, The detonation appeared to be stronger than remarkable for its penetrative loudness, and under any other conditions; the bucket was on repairing to the quarry one-half of the shattered, and fragments were picked up cylinder was found about 80ft. from the several hundred feet from the spot where the place where it originally stood, being then charge was fired. Finally, a charge was fired only stopped by a grass embankment. The at an elevation of 60ft. or 70ft., and illustrated other half was found in an opposite direction, the use of dynamite for distress signals. lodged against a pile of broken rock, which The results of these experiments speak so stopped its further progress. The iron plainly for themselves that comment on our showed a clean split, which revealed an ex-part would here be superfluous. We never cellent quality of metal. The bore showed saw experiments carried out in a more fair an extraordinary enlargement near the centre, and honest manner than by Mr. Nobel on measuring nearly 13in. across, whilst the the present occasion. He courteously measurements at the top and bottom of the allowed himself to be placed under crossbore were in each case lin., as before firing. examination the whole of the time, but in no It would appear that the power developed way was anyone's conviction weakened, but increased as it approached the centre of its rather strengthened. One gentleman, the length, becoming reduced again as it neared traffic manager of one of our large railways, the further end of the hole. Of course the was not quite convinced that railway compaexplosion was practically instantaneous. Both nies would run no risk in carrying the dynaends of the bore were open to the atmosphere, mite. Mr. Nobel, however, promised to there being no plugging nor tamping. The arrange a series of experiments to meet his strain on the metal must have been enormous views and to satisfy him on all points of to have thus compressed it around the centre doubt. For our own part, we are satisfied in of the bore, and to have rent such a mass every respect except one, and that is, with regard and sent its halves yards away in opposite to any chemical change which might occur in directions. the dynamite in course of time. True, Mr. Nobel stated that the material used on Tuesday was prepared several months ago, but it has occurred to us while writing that it is at least within the limits of possibility that a change might occur which might lead to spontaneous combustion, or might render the material dangerous under conditions in which it is now harmless. We would suggest to The application of this powerful agent of destruction to military purposes was next illustrated. It is of course unfitted for use, either in heavy guns or small arms, its very power being against it in this respect, as forcibly illustrated in the case of the cylinder just referred to. But it can be utilized in shells with great advantage; a time fuse We are, Mr. Nobel to experimentalize in this direc- manner in which the ends of the wire are ing space, as shown in the cuts. Collars, or tion, if he has not already done so. We think turned up at right angles inside the sockets, other small projections, are substituted in the with this the public mind would be at perfect the upper half of which has a hole adapted case where the rods are placed vertically. These ease with regard to the high efficiency of for their reception. The upper portion of fit into corresponding hollows in the sockets, dynamite as a blasting material and its per- these ends can be seen in the elevation in which are tightened in the usual manner. fect safety in transport and use. Of course, fig. 1. In fig. 2 the two ends of the wires xx, M. Bloch does not appear to consider his prinhowever safe or useful dynamite may be, after being bent at right angles, are brought ciple applicable to the reuniting of the broken the invention or discovery would be prac-into contact within the upper socket m, and links of a chain; or, at any rate, lays no tically valueless if it offered no commercial the lower one m', being placed underneath the claim to that particular use of it. advantages to either the inventor or the nuts e and e', make all fast. The sockets are however, inclined to think that it might be public. As it is, however, we understand rendered subservient to that purpose by that its economy is greater than that of simply altering the shape of the sockets. A ordinary explosives, inasmuch as it requires ready method of repairing the broken links a considerably less quantity to do the same of a chain would be of great value, as the acamount of work. As to the precise action of cident is of common occurrence, especially the ingredients in producing the astounding in mining districts. results they do, we know little or nothing. They lie at present a little too deep for us to determine with anything like exactitude. Nature is mysterious in many of her operations, and this is, at present, one of them. So much the more credit, then, is due to Mr. Nobel for his important discovery in converting one of the most dangerous into one of the most harmless of modern explosives. NEW METHOD OF JOINING WIRES. Tmatter of difficulty, and one requiring a good joint has always been a we 972 m m' m m m X M FIG. FIG 2 FIC. 3 FIG. 4 FIG, 5 THE ENGLISH COINAGE OF 1867. Tbronze moneys of the realm coined at the Royal Mint during the year 1867, has just been published. It is astonishing that the document should not have made its appearance at a much earlier period of the Parliamentary session. The necessary statistics must have been available in January last, and certainly they might have been put into their present portable form and issued to the public many months ago. It is not the first time that good ground of commuch skill and attention, whatever may be plaint has arisen in reference to the publication the nature of the substance demanding to be of returns of work done at the same establishunited. As a general rule, it may be taken ment, and no doubt somebody is to blame for for granted that the greater the number of the present delay. The Mint is a commercial joints in any structure, or, in other words, institution, of which the community at large the greater the number of individual parts, are the proprietors, and all accounts and inthe greater the inherent weakness of it reformation relating to its expenditure, its garded as a whole. It is for this reason income, and its workings should be promptly witness with satisfaction the efforts unceasand accurately rendered by the Government. ingly made with a view to improve our iron If the returns in question are to be made manufacture, to turn out rolled plates and public at all, they should be forthcoming at bars of a length and breadth exceeding their the proper time, and not six months after predecessors, so as to diminish the number of date. With this preliminary censure upon them required for any particular purpose. those whom it may concern, we may examine Evidently, the perfection of a girder, for ex- tapped slightly conically to assist the screw- and set forth the items exhibited in the return, ample, would be to have it all in one piece, ing on of the nuts, which is continued until and make our own comments thereon. So without any riveting or bolting together of the two half-sockets are brought tight home far as the gold coinage is concerned, the year component parts, but except for spans of to one another. This method is applicable 1867 was by no means a prolific one at the very limited dimensions, this would be an to the jointing of cords of all diameters, as Mint. In fact, not a single whole sovereign impossibility. At the same time, although well as to rods and axles, not merely among was born within its walls from December 31, we can never reach absolute perfection, yet themselves, but also to other objects. Fig. 31866, to January 1, 1868. Of half-sovereigns, we must not, on that account, relax our efforts shows the plan to be adopted when it is de- however, during that interval 992,795, weighto approach it as nearly as our means will per- sired to connect two wires with reference to ing 127,485-816oz., and representing, when mit. Casting a retrospective glance at early a third object. The lower socket m1 is forged struck, £496,397 17s. 11d., came into existdays, it is clear that the ancients possessed solid with a small bracket M, which, by means ence. The plethora of gold coin which but a very limited knowledge, or even idea, of a couple of screws, can be attached to any afflicted the Bank of England during the of the union of separate parts, constructively convenient spot, without in the least interfer- whole of the past year, and from which the speaking; and, omitting the combination of ing with the ordinary junction of the wires old lady still suffers, accounts for the small brick and mortar and masonry, so long as . It is of no consequence what the section demands made upon the Mint presses for the Nature assisted them, so long as they could precious commodity in 1867. The silver curprocure a gigantic balk of timber, they would rency was added to considerably in that year. make it subservient to their purposes. But The number of florins stamped and issued of that scientific and skilful arrangement by amounts to 423,720, equalling in value which a number of individually weak parts When a rope is the object in question, the £12,372, and weighing 154,080oz.; of shilare made equally strong as a solid mass of the interior of the sockets m and m is made lings 3,161,120 were minted, and these yield same material, they were completely ignorant, jagged, as represented in fig. 4, in order to in value £108,306, and in weight 303,840oz.; and the mysteries of bracing and the laws catch a better hold of the two ends X. Fig. 5 of sixpences, 1,362,240, value £34,056, and and theory of strains were to them a terra in- shows the method of attaching a cable or weighing 123,840oz., were added to the many cognita. rope to a shackle, where, as in the former millions-of a good, bad, and indifferent kind A telegraph wire from London to New York cut, a part of the interior of the sockets is--now circulating among her Majesty's fully and adequately represents the idea of jagged to hold the cable, and the other por- lieges. Threepennny pieces were turned out continuity. Rails are broken at every joint, tion grooved to grip the neck of the shackle, to the extent of 717,288 in number, £8,966 25. but the slightest disruption or break in the or of any other object which might be sub-in value, and 32,604oz. in weight. continuity of a telegraph wire places the whole stituted for it. This method of jointing tion to the four denominations of silver coins of it hors de service. The diameter of a wire would prove very useful and quick of appli- just named, there were struck, and distributed of this description is so small that a good cation in all cases of the breaking of cables, at the Queen's request, to certain poor recisplice is sufficient to join two pieces effectually, insomuch as it does not require any prepara-pients of both sexes, 16,830 Maundy coins, but when the size becomes increased other and tion or preliminary operations. It is ready, viz., fourpences, twopences, and pence, equalmore complicated methods must be resorted and can be applied at once, without loss of ing in value £141 18s., and in weight 6160z. For this purpose a method of union or a either time or labour. In applying this prin- The quantity of worn silver coin purchased by joint has been recently designed and patented ciple of joint to rods of comparatively large the Mint and recoined in 1867 was 376,142oz., by M. Bloch, which possesses some features diameter, their extremities are furnished with the nominal value of this being £120,000, and of interest, and some claims to success. It a kind of spur resembling in shape a swallow's its actual value £103,439 6s., the difference, is composed of, as represented in the annexed tail, which is inserted in the interior of the £16,560 148., showing the loss which the cuts, a pair of half sockets, tapped upon the sockets, and when the rods are placed in a pieces had sustained by abrasion in circulaoutside to receive the nuts that hold them to-horizontal position the nuts are screwed tion. This loss falls on the Treasury in the gether, when the two extremities of the wire home, and are not separated by any interven- first instance, but, in the shape of increased or rod are adjusted in their place. Figs. 1 estimates voted by the House of Commons, and 2 show this arrangement in elevation and it eventually has to be borne by the public. section; and the latter cut represents the Referring to the bronze coinage, we dis to. of the bar to be joined may be, as the interior We are indebted to our excellent contemporary, "Le In addi cover that in 1867, 5,483,520 pence, 2,508,800 hair on a cat's back in the wrong direction. two pieces of silex or common quartz be halfpence, and 5,017,600 farthings were A yellow tint in crystals of blende, of stron- gently rubbed together, they become luminous, struck. These equalled in value, collectively, tium, and of uranium, is that most favour-emitting at the same time a perceptible and £33,301 6s. 8d., and weighed seventy-nine able to the development of phosphorescence, peculiar cdour. This power of becoming tons. A handsome profit is exhibited upon and M. Becquerel has studied this phenomenon selfluminous is destroyed by subjecting the the coinage of bronze during the year, for the in crystals of sulphide of zine with great at- mineral to a high temperature, although the purchase money of the metals for making it tention and success. For this purpose he aid of electricity will, in some instances, was only £18,960, or £14,341 6s. 8d. less than employs an instrument of his own designing, suffice to restore it, but with a difference in the nominal value of the three denominations named a phosphoroscope, which is exceed- colour. There must be a distinction drawn of coin when issued. It is computed that the ingly ingenious, and the principle of which when electricity is resorted to as the actual number of bronze coins now in circu- is as follows:-The object to be accomplished originating power between phosphorescence, lation throughout the British Isles amounts is, first, to expose the substance to the rays of in the strict sense of the term, and ordinary in round numbers to 344,000,000, and their the sun and then to plunge it into sudden ob- incandescence. A piece of charcoal placed aggregate weight is 2,376 tons! The total scurity, and observe whether it emits the between the poles of a battery directly the number of pieces of money of all denomina- light it has previously borrowed. This little circuit is established, becomes at once incantions coined at the Royal Mint last year will apparatus consists of a metallic drum having descent and luminous, but not phosphorescent. be seen from the above statement, which has a hole pierced in each of its ends exactly Were no distinction made, nearly every subbeen drawn up very carefully, is 18,683,913, opposite to one another. Consequently, stance might be rendered phosphorescent by not an inconsiderable out-turn for a very when the instrument is placed in position, a so irresistible an agency as that of electricity, slack season. That establishment has suffered, ray of the sun entering at one of these aper- whereas mere luminosity does not per se connevertheless, and is suffering from the effects tures would pass out at the other were stitute phosphorescence. of the widely prevalent depression of trade. nothing interposed in the interior of the The poor workpeople of the Mint know this apparatus. To prevent this occurring, a fact to their sorrow, for their pay has not couple of metallic discs are placed in the inaveraged more than eighteen shillings each terior, parallel to the ends of the instrument, per week for many months past, and boys and are pierced with apertures of the same taking home about half that amount only. This diameter as those in the ends. The holes in will not be deemed an extravagant rate of the discs, however, are disposed in such a Before the Select Committee has HE progress of the "Electric Telegraph wages for a money-making concern like that manner that, while one of them is opposite on Tower-hill, and for the sustentation of one of the holes in the ends of the instru- been satisfactory lately, a result due entirely which for one year-1868-9-Parliament has ment, the solid part of the other disc is to the withdrawal of the opposition brought just voted the sum of £45,820. turned towards the other aperture. By this to bear against it by the various interested arrangement the passage of the rays of the telegraph and railway companies. It will sun from one end of the apparatus to the be remembered that terms were mutually other is constantly intercepted. These in- offered and declined by the Post Office and tercepting discs are turned by hand gear, are the telegraph companies previous to the apROM the Greek is derived the etymology fixed upon the same shaft, and can be rotated pointment of the Select Committee, but of the word phosphorus, signifying with a velocity of 500 revolutions per since the members comprising that committee light-bearer, and producing the well-known second. In order to observe the degree of have begun upon their labours in investigateffect of phosphorescence, which, however, is phosphorescence possessed by any body it is ing the Bill, and upon the several points they a property enjoyed by other bodies, and not placed between the revolving discs exactly in were specially instructed upon, certain terms always due to the same origin. It may be fine with the end apertures of the appa- have been arranged and accepted between caused, as in phosphorus, by slow combustion ratus. Directly the aperture in one of the the directors of the various telegraph compaor oxidization, which, when that substance is discs (let us call it the front one) comes oppo- nies and the Post Office authorities, such exposed to the air, gives rise to the formation site the hole in the end of the drum, the sub-terms to be subject to the approval of the PHOSPHORESCENCE OF BODIES. FROM of the compound phosphorous acid, expressed by the chemical equivalent of P O3. The term phosphorescence may be defined as that property possessed by certain substances of becoming self-luminous in the dark, whether the development of the luminous appearance be due to the cause we have mentioned or to any other. stance is illumined by a ray of light. At this moment the hole at the opposite end is covered by the solid part of the other disc, so that the substance cannot be seen while it is illumined. But so soon as the solid part of the front disc covers the end aperture and the substance is no longer illumined, that at There are one or two rather the other end is uncovered, and the observer, curious circumstances connected with the by placing the eye at it, can perceive whether oxidization of phosphorus which appear the body has become self-luminous, that is, almost paradoxical. The progress of the whether it emits the light it has just received process can be at once arrested by the in- from the sun. M. Becquerel* asserts that, by troduction of a little olefiant gas, C2 H2, or means of his phosphoroscope, he can estiby the presence of any essential oil. Bear-mate a phosphorescent appearance which ing in mind that the presence of oxygen is lasts only the 10,000th part of a second. indispensable to the luminous development, The colour of the phosphorescent light has it would naturally be concluded that the greater the quantity of that gas, the greater the energy with which the combustion would proceed. But the very reverse is the fact; the combustion ceases altogether in pure oxygen, and it requires the addition of nitrogen, hydrogen, or other gas, to start the operation. THE GOVERNMENT TELEGRAPH BILL. shareholders of the companies, and of the Select Committee. The companies accepting these terms are the Electric and International, the British and Irish Magnetic, the United Kingdom, the London and Provincial, and the Universal Private Telegraph companies. The main point of the arrangement is, that the various systems are to be purchased by the Government at the value of a twenty years' purchase at present rate of profits. For such members of the staff whose services the Government do not require to retain, and of those who do not wish to remain, a fair scale of compensation is agreed upon. Since the above arrangement was concluded, terms have been satisfactorily settled for the purchase of "Reuter's Telegram Company," whose property principally consists of the Lowestoft and Nordeney cable. Owing to the property being hazardous, some difficulty was occasioned in settling terms, but now that that arrangement has been concluded this further opposition is withdrawn. no relation to that to which the substance has been previously exposed, and, moreover, varies with the body experimented upon. Aluminium, when submitted to the action of the phosphoroscope, emits a red tinted light, no matter what may be the colour of the exciting rays. White crystals of blende shine with a blue lustre lasting for the hundredth part of a The preponderance of opinion on the part So far the explanation of phosphorescent second, while yellow crystals of the same sub- of the country, and of the press generally, in luminosity is exceedingly simple, being stance are resplendent with a greenish hue, favour of the Government acquiring the telecaused by actual slow combustion attended which changes to white when the velocity of graphs, would in all probability have sucwith the emission of light. When we turn rotation is very great. The diamond gives ceeded against the opposition the companies our attention to another cause of phosphores-out both blue and yellow rays, but the dura- were likely to bring against the bill, but the cence, the explanation is not by any means tion of the latter surpasses that of the former. opposition from all the railway companies equally satisfactory. Certain substances are Although the colour of the light to which a was a far different thing. Here we have a endowed with the property of becoming substance is exposed does not appear to in- large number of railway companies having luminous in the dark, after having been ex- fluence that of the phosphorescence excited, extensive telegraph property over their lines, posed previously for some time to the rays of yet the rays of the solar spectrum exercise some lines using these wires for the conveythe sun. This is very remarkable, and it a considerable effect upon it. Goloured ance of messages for the public, whilst all would almost seem as if they possessed the crystals of sulphuret of zinc remain luminous use them for the better transaction of their capability of absorbing light for the purpose for a long time after being removed from the own business, and more especially for the of future restoration when in the dark. The action of its rays, particularly if they have signalling of their trains, so that by the aid diamond possesses this property, as well as been subjected to the violet portion of the of the telegraph travelling might be rendered many other minerals. It is also very spectrum. In addition to oxidization, and safe and the company's property secure from strongly developed in the artificial sulphide the unknown cause we have just been de- damage. Great opposition was offered on of zinc, but not in the natural, or black jack, scribing, there are other origins of phos- the point, that the railway companies could as it is termed, unless accompanied with a phorescence in bodies. Friction is one. If not place the safety of their traffic in the slight degree of friction, which probably hands of the Goverument and of probably a brings the agency of electricity into play, similarly to the experiment of stroking the Scientifique." *For a detaile·l account of this invention, see "L'Annce newly organized telegraph staff. Their opposition has been successful to their best wishes, for railway companies are placed muneration; the Government obtain through of coal by Dr. Richardson and Mr. E. Lavnow, telegraphically, in a far more advanta- the Post Office administration entire control ington Fletcher. The folding plates are geous position than they have ever been of the telegraph; and it only remains to be carefully prepared and well executed. In the before. Their own telegraphic system for seen how, under the various arrangements, present instance, they represent the hot-air ordinary speaking, and, more particularly, the public will be served. Will the service machines of the monitor "Dictator," which that for special train signalling, will be left remain as it is, or will it, under the peculiarly were designed by Captain Ericsson in 1862, unreservedly in their hands to be managed proposed arrangements, become better, and and the engines of the Mahrousse," by and maintained by their own employés, and, carry out the intention expressed in the pre-Messrs. John Penn and Son. Altogether, we in addition, the erection and maintenance of amble of the bill, of providing a more expe- are pleased with Mr. Bourne's new work, all the Government wires passing over their ditious as well as cheaper mode of telegraphy. and look forward with interest to the treat lines are to be in their hands also. It is a The Committee are still sitting, but they have in store for us in the practical and descriptive somewhat paradoxical fact, but by this so far advanced that, with an alteration to portion of the treatise. arrangement what the telegraph companies one paragraph, they have declared the preformerly did for the railways, the latter are amble proved, and they are now engaged now to do for the Government. in discussing the clauses. One point may be noted, and that is, whereas the telegraph companies' arrangement is only binding for the present session, the arrangement with the railway companies is not only binding for this session, but also for the next. All the railway companies have severally agreed to these arrangements, the London and South-Western being the last. Upon the advantage or disadvantage of the proposed plan of the railway companies per forming the large share of the engineering work of erecting and maintaining wires, we have not at present space to enter into, but in a future number we trust to make some remarks upon this point, as well as upon the practical operations of the bill as passed. Under the present head we may of course notice "mechanical" arithmetic, which is here presented to us in the shape of a treatise This bill is only considered as a permissive on the slide-rule,* one of Virtue's-formerly bill, and, if passed this session (of which Weales'-rudimentary series. The present there is even yet some probability), a money bill will have to be brought in next session to enable Government to complete the necessary purchases. NOTICES OF BOOKS. is formed our readers of what was going T now about three months since we last work recognizes the value of the slide-rule, by the assistance of which the drudgery of computation is avoided. It contains a complete set of easy and simple instructions to perform all business calculations with unexampled rapidity and accuracy, and thus introduces this useful instrument to a new pose has been specially constructed by Mr. sphere of operation. The rule for this puron in the world of scientific literature. Since Hoare on a truly simple plan. One of the that time, many additions have been made to rules accompanies the treatise; it is of cardour bookshelves, in the shape both of new board, and has two slides of the same material. works and of new editions of old ones. If It is adapted for all ordinary purposes of calour readers feel disposed to blame us for our culation, and thus commends itself to any The purchase of the submarine cables from long silence on this head, we must plead the who have frequent arithmetical computations England was one of the points referred to increasing spread of practical science in every to make, and who desire to shorten the time the Committee to enquire into, but one which conceivable direction, and which must always and reduce the labour expended upon mere has not received much attention, beyond that take the precedence of more theoretical arithmetical workings. the fact has been elicited that the Govern- matters, however valuable they may be. ment contemplate the purchase of the various However, we will now commence to reduce Arrangements were consequently the array of books before us to a smaller settled with the Reuter Company and the Sub-compass, and in so doing we shall endeavour marine Company. The latter agreement to classify them, as a means of affording a deserves more mention, for by it the Post-readier reference to the several subjects upon master-General agrees to lease to the Sub- which they treat. First, then, in order, we will marine Telegraph Company, for a period of see what has been done in twenty years, the two cables to Holland (the property now of the Electric and International Company), and the cable to Nordeney (Reuter's cable), so soon as such cables may be transferred to the Government, upon-as the secretary of the company informs usthe following basis : cables. 1. One-fourth part of the gross receipts earned by all the cables to the Continent to be paid to the companies for working expenses and repairs to cables; but the amount to be received by the companies for these expenses is never to be less than a sum to be hereafter agreed upon. 2. Certain proportions of the gross receipts on London and country traffic, which are equivalent to about one-fourth part of the gross receipts, to be paid to the Government for the rental of land lines to the coast, and for the transmission of continental messages between London and any station in the United Kingdom. The Government to repair and maintain in good working order the land lines in connection with the cables and pay all way-leaves and dues to railway companies and others over whose territory the land lines pass. MECHANICAL ENGINEERING. CIVIL ENGINEERING. Under this head we have to notice a work of peculiar value, as well to those who design as to those who study the art of engineering We refer to the "Record of construction. Modern Engineering," in which Mr. Humber embodies a vast amount of practical information in the form of full descriptions and working drawings of all the most recent and And here we find the indefatigable pen of noteworthy engineering works. We need Mr. Bourne at work on a subject, the details not again point out the special value of such of which no one is better able than himself a work, having done so several times before. to place before the engineering profession. Besides, it speaks for itself; the very title He is now illustrating the progress of that indicates that, which a column of writing department of mechanical engineering which could no more expressively delineate. The comprises the production and transmission of volume before us-which is the first for the motive power by a treatise on modern steam, present year, the work being issued half yearly air, and gas engines.* Here we have examples -commences with a biographical sketch of Mr. of the most recent and approved types of John Fowler, who was president of the Instithese several classes of engines as are now tution of Civil Engineers for 1866 and 1867. in general use for pumping, driving ma- The frontispiece is an excellent photographic chinery, locomotion and agriculture. An likeness of Mr. Fowler, and the memoir is additional value is given to the treatise by interesting and suggestive to aspirants to the minute and practical description being engineering fame. Amongst the numerous accompanied by working drawings. In order articles in the present volume, we note as to leave nothing wanting that might render especially valuable those on harbours, forts, the treatise perfect, Mr. Bourne gives a and breakwaters, on the pumping station at critical account of all projects of recent im- Abbey Mills, and the main drainage scheme, on provements in furnaces, boilers, and engines. the Barrow and the Millwall Docks, works on Whoever, therefore, takes the work, will the Metropolitan Railway, the Cannon-street possess a fund of valuable information, which station roof, the Maquis and the St. Germans at the present time is distributed amongst viaducts. The plates are excellently lithothe scientific periodicals, and there often graphed, and the present volume of the but incompletely described, and frequently Record" is not a whit behind its predecesThe treatise is published sors. monthly, and will be completed in twentyfour parts, which are to be illustrated by about Mr. Grantham has just issued a fifth edition fifty plates and 400 woodcuts. In the first of his work on iron shipbuilding, which has and second parts now before us, Mr. Bourne been received with signal favour by those discusses in part the past, present, and future interested in this branch of constructive inof engines for generating motive power. The dustry. Like all other new editions, it has result of his investigations is that he finds been enlarged and improved both with respect the steam engine of the present day substan- to the text and the engravings, being brought tially what Watt left it, and a very inefficient down to the present period. The original thermo-dynamic motor; he further looks to form is retained, so that we have a small the supercession of the steam engine, at no and handy volume of descriptive letterpress, distant period, by simpler and more economical machines. An appendix to the work contains reprints of articles on Mr. C. Wye Williams' boiler projects, to which Mr. Bourne makes reference in the body of the work, and a valuable report on the evaporative value 3. If the submarine companies find it im-unillustrated. possible to repair either of the cables to Holland or Nordeney, the Postmaster-General, at his sole expense, shall, upon the certificate of a competent engineer, declaring the impossibility of repairing it, replace such cable, if it be shown that the international service requires it. 4. After the aforesaid sums are deducted from the gross receipts earned by all the cables, the balance to be equally divided between the companies and the Government. The bill and its objects as now arranged seem to present an example of the difficult art of pleasing everybody. The telegraph shareholders receive a large sum for their property; railway companies obtain what they required, and become more independent; the press will obtain what they petitioned for; the Submarine Company have the maintenance of the submarine cables at a good re Examples of Modern Steam, Air, and Gas Engines.' By JOHN BOURNE, C.E. Parts I. and II. London: Longmans, Green, Reader, and Dyer, Paternoster-row. 1868. HOARE, C.E. SHIPBUILDING. "The Slide-rule, and How to Use It." By CHARLES 1866, with Essays and Reviews." wood and Co., 7, Stationers' Hall-court. 1868. "Iron Shipbuilding, with Practical Illustrations." By whilst the plates-some of which are of very large size-are bound apart in a larger form.* Mr. Grantham gives us the early history and the progressive stages of the science of iron shipbuilding, so written as to be easily understood by all who desire to consider the subject. At the same time, the practical operations required in producing a ship are described and illustrated with care and precision. We not only have the details of the ships themselves, but also the particulars and drawings of the machines and tools used in the process of producing the various parts. When it is considered what an amount of work there is in an iron ship, and what a variety of operations have to be performed in its construction, and in the preparation of the materials used, and when we state that these processes, and the machines they involve, are faithfully described and carefully delineated, we may, at any rate, indicate the high value of the work. one this means. fied to its efficiency, but when the body of are drawn and the carefulness with which all the The eighth volume of the Transactions of the Institution of Naval Architects is now before us, being issued from the office of the Institute, 7, Adelphi-terrace. It contains the names of the members and associates, and a copy of their bye-laws and regulations, after which we have reports in extenso of the papers read and the discussions which took place at the annual meetings held in April, 1867. As these papers were reported and discussed by us at the time of the meeting, it is unnecessary for us here to notice them further than to call attention to their highly practical character, and to recommend them to our shipbuilding readers as containing much matter for serious reflection. We have somewhat reduced the collection of books before us, but there still remain a number for notice, and which we hope to dispose of next week. LEICESTER. To obtain space for an agricultural display, to We are glad to turn from such pretentious themes to Mr. Burgh's thoroughly practical treatise on the screw propeller,* Parts III., A small volume comes before us, ostensibly IV., V., and VI. of which are now before us. for the purpose of informing the public of Our readers are already aware of the scope the various methods of propelling vessels by and objects of this work, which are to give steam power, but really with the view of the engineering profession a standard book of proclaiming the author to be "the first who reference on modern screw propulsion. That used the screw in this country," and also the the fullest success is likely to be-nay, is inventor of Mr. Ruthven's method of hy-being-achieved will be at once admitted draulic propulsion as adopted in the "Water- when we state that amongst the list of con- THE ROYAL AGRICULTURAL SHOW AT witch." The author proves the above pro-tributors are the honoured names of Penn, position by the statement that "he com- Maudslay, Watt, Rennie, Napier, Dudgeon, menced a patent for propelling by two screws, Ravenhill, Humphreys, &c., &c. In Part III., on either side of the sternpost; but we have the concluding portion of insure the necessary amount of area in which being informed by the patent agent, just chapter on the geometry of screw propellers, to exhibit to the public the progress that mechanibefore the time allowed by law for enrolling which is illustrated by two full-page litho- cal art and the innumerable appliances of methe specification, that the screw had been graphs showing the geometrical construction chanical engineering have made since the last expublicly used at the stern for propelling of four different examples. Two other sheets hibition at Bury, has been a subject of grave consiboats in America, he abandoned the idea of of lithograph illustrate a screw propeller by deration to those to whom the selection of the site using the screw outside, and confined himself, James Watt and Co., and a Griffiths' screw was entrusted. After mature deliberation upon the in his specification, to employ the screw by John Penn and Son. Chapter IV. is relative merits of the various localities suggested inside a cylinder, fixed inside the vessel." written by Mr. Robert Griffiths, who gives to them, the committee decided upon Leicester as As we fail to see here the proof of the author's an interesting history of the screw propeller, the locale for the year 1868. This town-or, as we proposition, and have not the means of sup- of which he is the inventor. The geometry should properly say, the suburbs-present peculiar porting him outside his own words, we pass of this propeller is discussed by Mr. Burgh on to the hydraulic claim. This grew out in Chapter 5, Part IV., which is continued facilities for carrying into execution the determinaof the "success "obtained by the screw and into the next number. Part IV. is illustrated tion of the committee. Our readers are well aware cylinder principle, "which induced the writer with two plates showing the propeller and from previous notices in our columns of the advanto follow up the idea of propelling by the force lifting frame for H.M. gunboats of 50-horse tages which Leicester offers with respect to its of streams of water, and in consequence he took power, by James Watt and Co., a plate of central position, and the rapid communication out several patents for propelling vessels by the Mangin screw of H.M.S." Favorite," and which prevails between it and all parts of the kingWhether any of these methods a plate showing the Griffiths' screw fitted to dom. The programme for this year, according to proved practically successful—that is, beyond the "Lord Clyde." Chapter 6 is a brief the Royal Agricultural Society's rotation of tests for mere experiment—we are not informed, but notice by Mr. Charles Barclay on the geo-implements, included trials of steam and horse that they did not is clear from the author's metry of the paddle-wheel, which, although statement, that the important question, as hardly in keeping with the subject of the ploughs and cultivators, trials of the great family to the apparatus that should be employed work, is admissible as an original produc- of rollers and clod crushers, and of that induratfor giving the greatest quantity of momentum tion having no existence elsewhere. In ing race the brick machines. The experiments to the volumes of water with a given power, Chapter 7 Mr. Burgh enters upon a deyet remains to be solved." Then follows the scription of the modern screw propellers consolution, which is a machine which must "by structed by the most eminent marine en some artful arrangement be constructed to gineers of England and Scotland. These are supersede the tangential action" (present in they to which the bulk of the plates refer, rotary machines) "without loss of power." and which are highly valuable as the most "A machine of this kind it is intended to perfect examples of the present practice of submit to the public; and this is the chief the various firms. The four plates in Part V: end of the present treatise." We have in show respectively the six-bladed screw of the last ten words at least the truth. But the Egyptian Government steamer Leicester, £1,500, for the contributions of the then the public are invited to purchase the kich," the Griffiths' screw of H.M.S. "Lap- town to the expenses of the show were about, if not book under the impression that it has a wing," the Mangin screw for the " Bullfinch," exactly, the cost of preserving this land for trial. widely different end. The machine consists and an arrangement of twin screws. The In a fine undulating country, sloping gently of a rotary propeller revolving in a volute last part to hand contains the conclusion of towards the south, and but little shaded by trees, box, an idea which the author "attempted" the descriptive chapter on the modern screw the ground was, as might have been expected, to carry into effect thirty years ago. That propeller, and a portion of Chapter 8 on twin very much in the condition of one continuous halfhe did not succeed is patent to the whole screw propulsion. This chapter is written burnt brick, and if it had been the desire of the world, but he means to make another trial by Messrs. J. and W. Dudgeon, who have council to test the strength alone of the implements, at least on paper; whether he will ever had abundant experience on this special and their power of resisting shocks and sudden attempt it on a practical scale is very doubt-feature of the subject. As illustrations to ful, and whether, if he does, he will succeed is this part, we have the four-bladed right-hand strains, no more favourable conditions for such a Indeed, we have our doubts screw propeller of the "Allemannia," the test could possibly have been obtained. The work as to whether the system of hydraulic pro- three-bladed left-hand screw propeller of the of lifting up, turning over, and to a certain extent pulsion will ever prove a success-that is, 'Surat," the four-bladed screw of the pulverizing, great cakes of the earth's crust, as we capable of universal application alike to large Agincourt," and an ordinary four-bladed saw it performed, reminded us of the descriptions and small vessels. În ships of the latter adjustable screw propeller, as used in the given by Anglo-Indians of the labours of the class we have ourselves witnessed and testi- Royal Navy, each of which forms a study in ryots undertaken every seven or eight years, in itself. The great value of these drawings which they actually turn over the earth for a conconsists not only in the correctness of their siderable distance with a crowbar, and split it up detail, but in the clearness with which they by using the bars almost as wedges. The land was fortunately not, strictly speaking, heavy; indeed, under ordinary circumstances, it would have been rather light than otherwise, but the extent to which it was caked and hardened ren still more so. On Iron Shipbuilding, with Practical Examples and Details in forty plates" BY JOHN GRANTHAM, Memb. Inst. Naval Architects, &c. London: Lockwood and Co., 7, Stationers' Hall-court. 1868, 66 "Char "Treatise on the Mechanical Means by which Vessels "Modern Screw Propulsion." By N. P. BURGH, Enare Propelled by Steam Power." By WILLIAM HALL, C.E.gineer. London: E. and F. N. Spon, 48, Charing-cross. London: Longmans, Green, and Co. 1868. 1868. with the first-named classes commenced on the 9th inst. The ground chosen for the out-door trials was a farm of about 130 acres, about two miles south of Leicester, and immediately adjoining the Midland line. farm had by agreement with the occupier been All the tillage portion of this left fallow this year, an arrangement which cost the Society, or, perhaps we may say, the town of |