THE LONDON: FRIDAY, JULY 10, 1868. THE PATENT OFFICE LIBRARY the shortness of the range-1,000 yards not being attainable. was supported by a considerable number of gentlemen interested in promoting the extension of public museums and libraries. On the occasion to which we have referred, The learned chairman having stated the ob- sixteen rounds were fired, out of which two ject of the meeting, and several gentlemen took effect, which was not bad considering MECHANICS' MAGAZINE. having spoken upon the subject, Mr. John the comparative smallness of the object aimed Holmes, D.L., proposed the resolution:--- at. These two were the fifth and sixteenth "That the present condition of the museum shots; the fifth penetrated the earth on the and library of the Commissioners of Patents roof to a depth of 4ft. 4in.; it was dug out, is not such as befits national collections, and and a live shell dropped in its place, and that it is the duty of the Government, with fired, the result being that a crater was the accumulated surplus revenues of the formed in the earth, but no damage was done Patent Office, to take steps for their more to the roof. This might have been expected, efficient accommodation, in the interests of for the reason that the shell not having the large and growing body of inventors, penetrated the concrete, but having still 8in. scientific and literary men, and skilled of earth beneath it, had little or no resistartizans and mechanics, to whom the institu-ance in the surrounding loose soil, and its tions in question are capable of rendering im-force was exerted upwards. After the sixth portant practical assistance." round, 2ft. of earth were removed, so Captain Selwyn, R.N., proposed that the that shell No. 16 had only 3ft. of earth to general council of the Public Museums and penetrate. It did not, however, get through the Libraries Association be requested to it, merely making a crater 4ft. in diameter make, in concert with other organizations and 2ft. 2in. in depth. So far the experirepresenting inventors and working men ments went to show that under such condigenerally, arrangements for bringing the tions, the structure was proof against the views advanced in the foregoing resolution 13-inch shell. It remained, however, to be to the notice of her Majesty's Government. seen what could be effected by shelling the It was also resolved that petitions to Parlia-bare roof. To this end, the earth was ment be signed by the chairman in the name removed from the Plymouth casemate, and and on behalf of the meeting, and that the vertical firing from the 13-inch mortars Lord Lichfield and Mr. A. H. Layard be was resumed on Tuesday last. In all, thirtyasked to undertake their presentation. In four rounds were fired, none of which, the face of the vast benefits that would accrue however, took effect on the spot intended. to the nation generally, and the working Two shells fell on the earth upon the adjoinclasses in particular, by the adoption of the ing roof, and two struck the granite base of measures we have indicated, we ask the the structure, thus giving about the same public to give their strenuous support to the proportion of hits as on the previous occasteps the members of the Free Libraries As- sion. The mortar practice was discontinued sociation are initiating. Undoubtedly, a very after the thirty-fourth round, but it is to be small accession to our existing knowledge of resumed on a future occasion. technical affairs would conduce to a great The second part of the experiments conadvance in the march of improvement, and sisted in horizontal firing from the 10-inch undoubtedly also the only way to obtain thi-gun, with live shell and 48lb. powder charges, accession of knowledge is to provide a des pository for it where it may be of use to the world, and not lie hidden under a bushel. THERE is an association at work which is endeavouring to effect a great good for the public, and to aid materially in promoting technical education. That society is known as the Public Museums and Free Libraries Association, and its objects are to open the national collections on week-day evenings, and to promote the adoption of the Free Libraries and Museums Acts. Amongst other matters it is prominently bringing forward, are the very inadequate accommodation of the Patent Office Library and the Museum, and the great inconvenience of having them separate and apart from each other. London really possesses no great technical and industrial museum, because the only institution that could be made to occupy that position is cooped up in an iron shed at South Kensington. The shed is not half spacious enough for its purpose, and it is situated far away from the dwellings, the workshops, and the offices of those to whom it might be of use. Similarly, the finest modern scientific library we have is banished to the top storey of some offices in Southampton-buildings, where there is not nearly enough room for the books, which are daily increasing in number. Granted, that it is a great improvement on the old "sewer," as it used to be called, and the half-dozen black holes branching off from it. But that is not enough. We want to see the library and museum combined and established in a manner befitting a national institution. We want to see the collection of books and models made available for reference RECENT GUNNERY EXPERIMENTS bars behind, and splintering the oak beam in together, and we want to see more room for the books which are received day by day, and AT SHOEBURYNESS. which must take their chance of getting placed FOLLOWING up the course of events at It is, to our mind, a great pity that when arrangements were being made for the New Patent Office library, they were not made on a scale commensurate with the importance of the institution, and so as to include the combination of library and museum. Practically, the one is of no use without the other, and practically, too, the latter will soon cease to be of the little utility it is to inventors at present, as its small space will forbid the addition of modern models and machines. We are, therefore, heartily glad to see the matter taken up as it now is by the council of the association to which we have referred. They have our best wishes in their work, and we would urge all those who can assist them to do so by all means in their power, as they are endeavouring to effect a great public good, and from the purest and most unselfish motives. We call attention to some notes upon the subject which have been issued by the association, and which will be found on another page. We also call attention to a meeting which was held on the evening of yesterday week, at the Society of Arts, for the purpose of urging upon the Government the duty of placing upon a footing worthy of national institutions the public inuseum of inventions and free scientific library connected with the Patent Office. Professor Leone Levi occupied the chair, and against the Plymouth and War Office casemates. The first round was directed against the Plymouth target. It took effect on the second curved plate, on an indent made by a previous shot, bending one of the vertical the interior over the port. The second round was the same as the last, and hit nearly the same place, with a smashing effect. It damaged the inner layer of 5in. iron, breaking up the structure in the immediate vicinity of the shell fragments of which practical value, with regard to the point at were scattered inside the casemates. About Since the previous firing, the experi- a foot of one of the 3in. bolts projected in mental casemates had been covered with the rear, while its head was sheared off and earth, edged round by bags of sand, to a thrown to the front. The third shot was height of 5ft., with the view of testing the aimed at nearly the same spot, and told with effect of the vertical fire of 13-inch land- tremendous effect. It cleared out the whole service mortars on the concrete or brickwork of the three 5in. layers of plate and roofs of those structures; at the same time, it bars completely for a triangular space of 2ft. was intended to ascertain what accuracy of by 2ft. by 2ft. 7in., smashing for a length of fire from mortars could be got for pitching 4ft. the 12in. oak balk over the porthole, shells from high elevations of range on so and bending the 14in. iron plate by which small an area as the top of the Plymouth it was backed. About a ton weight of iron breakwater model, which is only 22ft. by plating, held together by a twisted 3-inch 21 ft. superficial area. 'The shells fired bolt, was forced from over the port against weighed 2071b. each, and were all loaded with the rope mantlet, which had its 3in. iron sand, equivalent in weight to their bursting supporting rod bent, the explosion of the charge of powder-i.e., 103lb., this course shell firing the mantlet itself. being adopted in order to prevent all chances of 5in. iron, weighing about 24, 2 and icwt., of accident to the buildings, which certainly were hurled to the rear to distances of 120ft., stand in reasonable fear of damage from 80ft., and 90ft. respectively. Besides these, fragments of live shell. This substitution of smaller masses of iron and debris were sand for powder made no difference in the scattered in all directions, the flooring of the practice as far as placing the shell was con- casemate being strewn with fragments. cerned, because, with live shells, the time fuse would not explode the shell until after its lodgment was effected. It is, however, to be questioned whether the sand might not have some effect upon the flight of the projectile, inasmuch as the sand, being of a heavier specific gravity than the powder, did not fill the shell, and might disturb the steadiness of its flight. The range was 900 yards, and the mortars-for there were two -were trained by Lieut. Ellis, who made admirable practice, considering the angle of the mortars had to be altered on account of These pieces After this, attention was turned to the War Office casemate, into which a 10-inch shell was put. The shell struck the 44-inch plate, backed by 7 inches of concrete, a 2-inch skin, and a pier of concrete 8ft. deep, cased in a -inch skin. The shell penetrated to a depth of 10in., exploding in the concrete, which it blew, with its own fragments, into the casemate. The skin of the concrete pier was split open from top to bottom, and a portion of the back plate was driven out. Round No. 5 was fired with a Palliser shot, which struck the War Office casemate upon the A or 8-inch plate section. The shot was buried in the plating, the base of the shot being 44in. from the face of the plate. Round No. 6 was directed against the B section of the casemate, which, it will be remembered, consists of 4-inch plating on 7-inch channel iron backing, a total penetration of 314in. being effected. The seventh and final round for the day was aimed at the C section, which consists of a 6-inch plate backed the same as the last. The shot struck between two stringers, entering the plate, and making a slight crack between its own and a previous shot hole close by, the total penetration being 38 in. portion, in length 3ft. 6in. The third vertical plank certainly not against the mounted plates. It On Wednesday morning the vertical firing The great event of the day, to which all were looking forward, then followed. This consisted in a salvo from the 15-inch Rodman gun, and from the 12-inch, 10-inch, and 9-inch rifled guns. These guns were trained against the 15-inch portion of the Plymouth casemate, and were connected together and fired by the Austrian frictional electrical machine. The three guns were fired simultaneously; the 10-inch gun, although its tube exploded, was not discharged. As we were unavoidably absent upon this occasion, we append a description of the results, as given by the correspondent of the "Standard," an accurate and reliable authority. He states that the CHATHAM. To sum up the results, as far as the experiments have gone at present, they serve to THE SOCIETY OF ENGINEERS AT indicate generally a high degree of resisting power in the Plymouth shield, and a still higher in the War Office casemate, consider-THE members and associates of the Society ing the conditions under which they were of Engineers made their second excurfired at. For it is to be borne in mind that sion of the present season on Friday last, on the hit or miss chances of war, the ever vary- which occasion they visited the Chatham ing range and angle of fire, were elements Dockyard extension works. Permission totally absent from the recent experiments. having been previously obtained from the Shots took effect on the target between the first The deliberate aim, the short range, the many Lords of the Admiralty, a steamer was and second vertical 12-inch struts, about 3ft. nice calculations, are matters which would chartered, in which a pleasant run was made from the proper right side of front. The upper 5- be entirely precluded from entering into the down the Thames and up the Medway, inch plate was broken away right up to the end over calculation if such forts were manned by such luncheon being served on the way. The a somewhat triangular area, measuring at top 2ft. 4in., at base 4ft. 9in., by the whole width of the guns as were recently turned against them. company numbered over a hundred, and plate 4ft. 14in. A large irregular mass of the lower But beyond this we have to look at their included, amongst the members and asso3-inch face-plate was also carried way, and three comparative merits. And here we find that ciates, Messrs. Baldwin Latham (president pieces smashed and fractured by a Rodman shot on if the three 5-inch plates offered the re- of the Society), F. a previous occasion in the end bonnet plate were sistance they did, what might we not expect president), W. Bryant (viceJames Hendry, W. Adams, jarred out and thrown some distance to the front, one measuring 15in. by 15in., and weighing about from a single plate of the combined thickness J. H. Adams, Alfred Williams (honorary 2cwt., another 2ft. by Ift., weighing about 34ewt. of the three? Of course, it is only a simple secretary), Perry F. Nursey (auditor), G. W. (ten yards), and the third 1ft. by 8in., weighing rule of three sum to prove the greater resist- Harris (secretary), Westwood, W. Hendry, cwt. The upper plate first referred to was flaked ance of a solid 15-inch plate as against three A. E. Stephenson, G. Waller, F. away in two pieces, one measuring 2ft. 7in. at one end, Ift. 8in. at the other, in length 4ft., and weigh- 5-inch plates. Prima facie a case was made out Houghton, John Blackbourn, John Pinch18cwt., was thrown 14yd., and the other piece, against the 15-inch plate of Sir John Brown beck, Lewis Olrick, Henry Gore, &c. measuring 2ft. by 2ft., and weighing 7ewt., 10ft. to and Co. But then it was simply stood on edge Amongst the visitors were Capt. Webb, R.E., the front. On the ground before the target there upon the ground, and, supported only against Capt. Clarke, Mr. J. Beattie, locomotive were also a great number of splinters, some of considerable size. The Rodman shot struck near the two vertical bars, was fired at right and left. superintendent of the London and Southtop of the bottom plate, 3ft. 5in. from the base, and Had it been fixed in position, as the others Western Railway, Mr. C. E. Cockraft, and 29in. from the proper right end. It smashed in to a were, very different results would have been Mr. W. R. Fossett, both of the Admiralty. On depth of 15in. a great circular indent 16in. in dia- arrived at, although even then not the best arriving at Chatham, the party landed at the meter, and broke the second plank of the middle the Atlas plates could show. And for the Admiralty pier, where they were received by layer of 16-inch vertical planks, which also received a heavy bruising blow from the 12-inch gun, the reason that the plate in question was the first Colonel Pasley, R.E., the engineer-in-chief plank being bent over its whole width. It took out a ever rolled of that thickness, and was simply of the works, Mr. H. J. W. Neville, resident notch from one side 16in. across and 14in. in, buckling purchased by the Government to test com- engineer, Mr. E. A. Bernays, clerk of the to the extent of 5in. the bottom part of the broken petitively against the hammered plate, and works, Mr. Gabrielli, the contractor, and Mr E. The Daniel, C.E., manager for the contractor. reckoning has arrived. In any case, the works arm or tie of wrought iron, and each will After a cursory glance at the machine shops in hand are highly advisable, and have been therefore be most suitable to resist the parof the dockyard, where were some ingenious judiciously determined upon, because Chat- ticular strain brought upon it. Although circular planing machines, and a powerful ham is so difficult of access to a foreign fleet, there is no example of construction in which it plate-bending machine, in which 9-inch owing to the narrow and winding character is easier to determine the amount of the strains, armour-plates had been bent, the party pro- of the Medway. When the works are finished and to apportion the metal to resist them, ceeded to the extension works. The progress it is in contemplation to close the yards at yet at the same time a crane works more made is very remarkable, considering the Deptford and Woolwich, and possibly those within its safe load than girders or pillars. short time which has elapsed since the com- at Sheerness and Pembroke. Thus all the There are so many fortuitous circumstances mencement of the works. work connected with the construction and attending the working of a crane, that a large The extension docks are fast rising upon repairs of the royal navy is expected to be margin must be left for contingencies. a large tract of marsh, formerly known as concentrated at Chatham, Portsmouth, and incessant jerks and violent concussions it is St. Mary's Island, which covers an area of Plymouth. liable to produce an impactive force that about 320 acres, and lies to the north-east The works are intersected by tramways, demands special precaution to be safely enof the present yard. This island, which at over which haulage of materials is constantly countered. It is probably for this reason every spring tide was submerged, was pur- going on, eleven locomotives being engaged that the employment of cast iron has been chased by the Admiralty some years since in the work. One portion of the ground is confined, similar to the case of railway for the purpose to which it is now being con- devoted to the manufacture of bricks, which bridges, to the smaller specimens. A material verted. Soon after their acquisition of the are produced entirely by convict labour. Last of so well known treacherous a nature cannot land, the Admiralty enclosed a portion of it year the convicts made 17,000,000 of bricks, be safely relied upon, where sudden and with a river wall 1,100yds. in length. Double and during the first six months of this year violent strains may be brought upon it at any rows of sheet piling were driven, the earth they have made 10,000,000, machinery being moment. Owing to the crystalline instead of between them dredged out down to the gravel, used in their production. Some of the fibrous condition of the particles, they are and the space filled in with concrete. On machines are by Porter and Co., of Carlisle, more disposed to separate under the action this, at a point above the level of the low others are by Mr. Murray, of Southwark, and of an instantaneously applied momentum, water spring tides, is built a wall of brick-which we purpose shortly to describe fully. and they are wanting in that elasticity nework in cement, with concrete backing, 24ft. The five of them at work on the marsh make cessary to enable them to resist strains of a in height. It was begun in 1858, and finished about 800,000 bricks weekly. One peculiarity tensile character. in 1864. A further length of the edge of of this large brickfield is that the covers, to the island is protected by a stone embank-protect the bricks from rain, are fixed, and ment, 1,550yds. long, having a slope of two have sliding panels-a plan which is found to one, supported on piles, and rising 4ft. to be cheaper and more cleanly than the old above high-water mark. This wall is still custom of protecting the bricks with straw. in progress, and will be completed this year. The total number of convicts now engaged It is constructed wholly by convict labour, on the works is 1,150, out of about 1,400 in and forms no part of Mr. Gabrielli's contract. the prison. About 250 men are working in Another embankment, 800yds. long, consist- connection with the convicts, and the paid ing of vertical river wall, is in progress, and workman engaged on other parts of the island this comprises all the work near the river. number about 1,000. After inspecting the works, the party were conducted by Colonel Pasley over the new ironclads "Monarch" and "Hercules." They eventually returned to their vessel, dining on board on the way up. Off Gravesend a Spanish man-of-war-the "Vittoria ". manned yards, upon which the vessel carrying the Society of Engineers steamed round her, dipping her colours and cheering, the compliment being returned by the Spaniards. The band of the 2nd Surrey Volunteer Rifle Brigade-in which corps the president of the Society is a captain-was on board, and played the National Anthem. The band added to the pleasure of the trip by performing a variety of well selected and well executed pieces of music. Altogether, the trip was the most successful ever undertaken by the Society. WROUGHT-IRON CRANES. The Wrought-iron cranes may, similarly to girders, be constructed either upon the lattice or the plate system. In the latter, they in reality belong to the tubular type. principle of their design is very different from that governing the ordinary examples, and it is no longer a question of apportioning the metal according to the relative duties of jib, tie, and post. Those distinctive features are lost, or, rather, merged in the general framework of the crane, which is made strong enough to withstand their individual as well as joint influence. Mr. Fairbairn was the first engineer to introduce wrought iron tubular cranes, which, by dispensing with the common arrangement of jib and tie, allowed more headway to the load to be lifteda great advantage in the shipment of heavy bulky articles. The solid sides are, moreover, well adapted to resist the sudden jerks to which a crane is constantly exposed. At the same time, lattice-sided cranes, or those in which the sides are braced together by open trellis work, have their advocates. They are lighter in appearence and cheaper in construction, but for very heavy cranes intended to lift up to twenty tons, the tubular form is, upon the whole, to be preferred. It becomes difficult to adapt the diagonal bars in the web to the form of the crane without multiplying them to an extent that entrenches considerably upon the plate principle. Moreover, stiffness is one of the most essential qualities belonging to a crane, and although the strength of a structure is not necessarily a function of the stiffness, yet they can be more intimately combined in the solid than in the open web system. Lattice bracing is admirably adapted for resisting strains, of which the amount and direction are accurately determined, but should there exist any confusion and uncertainty with respect to the manner in which they act, or the direction in which their components might be resolved, it is not so safe a medium as its rival. It was for this very reason that plate girders, or, more generally, the solid web system, was the first adopted in girder work, and for a long period prevented the introduction of the other type of construction. The contract works consist, in the first place, of three large basins, the total water area of which will be seventy-four acres, the depth of water in each being 30ft. at highwater neap tides. The first of this series of basins-the one nearest the town of Chatham-will be a repairing basin. The second, which is situated in the centre of the reclaimed marsh, will be occupied by ships having their engines fitted. In the third basin vessels will be fitted out before proceeding down the river. The first of these basins is greatly advanced, the north wall being completed for the whole length, up to the level of 10ft. below the coping. In the second, the trenches for the north and south walls are in progress; whilst in the third, the north wall only has been commenced. Besides the three basins, there are to be four graving docks, of which two are now in course of construction. Each of the graving docks will be 508ft. long, 80ft. wide at the coping, 28ft. 6in. depth of water at the highest level HERE is no species of construction that of the neap tides, and 41ft. 6in. from floor has better speel of the gradual abaa to coping level. The two graving docks now donment of timber, and its substitution by in course of construction, and the repairing its now favoured rival, iron, than the ordinary basin, are to be finished by October, 1869, crane. The old upright post, the square jib, and the fitting, or "factory" basin as it is have, except in a few instances, yielded to called, is to be finished in 1870. Besides the the new material. Timber was, in this instance, basins, docks, and river boundaries, the as well as in many others, succeeded directly, foundations of the future factories are nearly not by wrought iron, but by its fellow, cast; completed, and these will cover an area of and the smaller descriptions of cranes, parOutside and below the works ticularly those of a movable type, are mainly the river will have to be deepened, to permit composed of that substance. The nature of the passage of the heaviest men-of-war into the strains induced upon the various parts of the new dockyard. H.M.S. "Porcupine" is a crane are favourable to the employment of therefore now engaged in surveying the bed cast iron, and, what is more, allow of its comof the river, to learn what shoals it will be bination with wrought iron-a union by no necessary to remove. In carrying out the means safe to attempt in the majority of new works the Government had to take pos- instances. Signal failures have attended The strains upon the various parts of session of a public pier called Gillingham the combination of cast and wrought iron, in girders, especially upon the sides or web, Bridges, but the Admiralty have agreed to the case of girders, but they were perhaps were but very imperfectly understood, at build a new pier lower down the river at a cost quite as much owing to the unscientific the best, in the infancy of railway of £40,000. The estimated cost of the exten- manner in which the structures were designed, bridges, and the solid or plate girder sion works is £1,250,000, of which sum as to any inherent fault in the material. At offered a solution of the difficulty. Only £437,564 was expended at the close of last the same time, although engineers understand make the sides thick enough, and stiffen them year. It is confidently expected that the at the present day the subject of strains at intervals by extra strips of metal, and the estimate will not be exceeded, but of this we much better than they did in the infancy of strains might go in any direction they pleased. have some doubt. For the sake of the nation railroads, yet great care and precaution are It was a matter of no moment to the enwe hope it may not be, but our experience necessary in dealing with the two metals gineer whether the girder was designed upon of estimates has invariably been associated together. In a cast-iron crane, the post and scientific principles or not, provided it was with "extras" ad lib., when the day of jib will manifestly be of a cast metal and the strong enough, and the requisite strength fourteen acres. was ensured at an enormous sacrifice of is no difference between radiant heat and Applying the foregoing information about material, a corresponding disregard of radiant light but that of "wave-length." subjects at present lying among the outside economy and in utter defiance of all accurate This at first seems very strange, because our boundaries of human knowledge to the recent and mathematical reasoning. The substitu- senses convey to us the impression that there experiments devised by Dr. Frankland, the tion of open diagonal bracing, where each bar is a very great difference between heat and results attained by the latter will now acts as the direct channel or medium for light, but the error is caused by the short probably be read with some interest. His resisting one strain, and for resisting one range of action of our senses, not by any experiments deal with the effects upon light strain only, evidently was the result of the great difference in the phenomena. The hand of pressure made to act upon luminous accurate application of theory to practice. is sensitive to the long slow waves, and informs sources. Dr. Frankland, after pointing out To apply it thoroughly and successfully us of the presence of heat, but it is practically that the more the pressure of the outside air necessitated a minute and scientific in-insensitive to the quick short waves of light; is increased the more luminous will it make vestigation into the whole question of the consequently, if we thrust our hand into a the flame of the common spirit lamp, extheory of strains and the determination of room through a hole in the wall, the nerves inhibited a new experiment, showing how to formula and theoretical rules to guide the the hand will tell us whether the room is hot make the oxyhydrogen flame luminous. He designer in duly proportioning his material. or cold, but not whether it is light or dark. took a strong iron cylinder, with the oxyhyIn a tubular or box crane, the cross sections The eye, however, is very sensitive to the drogen flame burning inside, and plugged the made in the direction of the radii of the short quick waves, which we call light. Pro- open end of the cylinder by screwing into it different curves of which its form is composed, fessor Tyndall proved the eye to be very in- a thick circle of plate glass mounted in an increase in size from the top to the bottom, sensitive to radiant heat, by bringing a sheaf iron screw flange. Thus the flame inside and are a maximum at the ground line, where of intensely hot dark rays to a focus with a continued to burn under a constantly inthe leverage to fracture it is greatest. Equal lens, so that at the focus iron was quickly creasing pressure produced by the tension of care and skill is required in apportioning the made red-hot. He found that he could bear the gaseous products of combustion, which sectional area of the different sections of a to place his eye in this focus for several pressure was registered by means of a gauge, tubular or of a lattice crane, for the time is seconds without inconvenience, but that his in order to avoid danger. As the pressure gone by when the strength of a structure was hand could not bear the same heat for an upon the surface of the flame increased the synonymous with its weight, and size was the appreciable length of time. In trying this light grew brighter, till, at a pressure of only standard of stability. experiment the eyelids must be protected from about 150lb. to the square inch, the light was the hot rays, and the best way to do this is to nearly as bright as that of a common candle. punch a hole as big as a pea in a piece of This apparatus had been worked up to a metal, and let the rays enter the eyeball pressure of 500lb. to the inch, but this was through the orifice. not done at the lecture, for the sake of absolute safety from accidents. MOLECULAR INFLUENCE UPON AT By very many other experiments, he showed that the same law seems to hold good in all gases, namely, that external atmospheric pressure increases the luminosity of flames. Thus most of the waves emitted by all orT the closing meeting at the Royal Insti- dinary sources of light are invisible. This tution, Dr. Frankland brought forward may be proved by throwing the spectrum of some new experiments upon light of a very the electric light upon a screen. In the interesting character, proving that external spectrum all the rays in light are "unrolled," pressure acting upon the ponderable molecules so to speak, and spread out in regular order, In fact, it has long been known that common which throw out waves of light, exerts con- the longest waves at one end of the spectrum gas gives out a little more light when the siderable influence in modifying the character and the shortest at the other. Now, the barometer rises, and decreases in luminosity of the resulting luminosity. As this is rather shorter waves, near one end of the spectrum, as it falls. The lecturer also showed that an abstruse subject to the majority of readers, are visible to us, beginning with the violet or some few flames are intensely luminous perhaps a brief summary of modern philo- indigo, and ranging down through blue, which contain no solid particles liberated for sophical opinions relating to light may make green, and yellow, to red, the red rays being a moment during the process of combustion. the matter clearer. The ultimate atoms com- the longest and slowest which can be seen The burning of metallic arsenic in oxygen posing what is called "solid matter" have by the eye. But when the red is reached, gas was an example shown, and although the never been seen, because, if such atoms exist, we are not near the end of the spectrum; in light was very brilliant, no solid particles were billions of them placed end to end would fact, have only reached its middle. Beyond present in the flame, because both arsenic occupy the length of less than a single inch; the red, another length of separated rays and its oxide are volatile below the point of consequently, they are utterly beyond the ken falls upon the screen, quite invisible to the redness. He proved that the luminosity of of the most powerful microscope. These eye. How, then, do we know there are rays flames of this kind increases with the density atoms are believed by Messrs. Stewart, Tyn- there? Because modern philosophy has of the gases and vapours burning, or prodall, Thomson, and other philosophers of the made an instrument more delicate than any duced by the combustion, the greater the same high school, to be in a state of incessant of our senses, to make known to us the density the greater being the amount of motion of a true or modified vibratory cha-presence of these rays. The little thermo-light produced. The experiments will be racter. This motion is what is commonly electrometer will indicate the presence of found described in detail in the "Engineer" called "heat," that is to say, that when the slight quantities of heat, which the nerves in of June 19, and as we are now dealing with hand is laid upon a lump of solid matter, the the hands are incompetent to make known to principles, space cannot be given to enter atoms hit against the nerves in the fingers, us, and which are too feeble to be registered into minuter particulars. By other experithe nerves carry the motion or sensation to by the common thermometer. The thermo-ments, Dr. Frankland proved that the spark the brain at a speed of about 280ft. in a second, electrometer proves that the spectrum of the from the secondary wire of an induction coil and the human being feels what he calls electric light is twice its visible length, also is brighter in proportion to the density of the "heat." The less the vibratory motion of that the invisible portion of it contains eight gas by which the spark is surrounded. In the solid the lower is the temperature, till at or nine times more heat than the length connection, therefore, with the foregoing parlast the hand imparts heat or excess of motion which can be seen by the eye. ticulars, the following table, compiled by the to the solid, instead of the solid imparting it to Such, then, is the nature of light, according lecturer, is of value :the hand, and this latter sensation is called to conclusions drawn from facts and experi"cold." There is a point at which atomic ments down to the latest date. For the past year motion would cease, but such a degree of cold or two, Dr. Balfour Stewart, F.R.S., Superinhas never yet been produced by man upon tendent of Kew Observatory, has been trying earth. The atoms in moving throw out waves. to bring the interstellar ether more under A fluid infinitely finer than air, and known immediate control, analogous to the experias the interstellar "ether," is believed to fill mental control we, to some extent, possess all space, and to permeate all solid bodies, over the gases. But the task is very difficult, bathing the vibratory particles. The expla- because ether cannot be bottled up like a gas nations given by philosophers of the causes or liquid, in consequence of its power of of all the phenomena of optics and the undu- passing between the atoms composing all latory theory of light, rest upon the assumption solid, liquid, and gaseous substances. To of the reality of this "ether." The atoms, then, confine it like a gas seems as hopeless a task cannot move without throwing the ether into as the attempt to carry water in a sieve. If waves, any more than a stone can swing in experiment should prove that ether cannot the ocean without moving the water, neither pass through some of the forces which pass can the ether move without altering the from particle to particle of solid bodies, motion of the atoms. For these reasons, when such, for instance, as magnetism or electria warm body is placed near a cold one, the city, the attempt to imprison ether might not first loses and the other gains motion by an be so futile. There are a very few phiinterchange of waves, and the heat tends losophers who fancy that magnetic pheno-T Zandvoort was interrupted last week. The to equalize itself in both. The waves thrown off by moving atoms differ in length, most of the shorter waves being what is known as light, and the longer waves being called radiant heat. Hence, there mena are the results of etherial and molecular : RELATIVE DENSITIES OF GASES AND VAPOURS, Hydrochloric acid Carbonic anhydride Sulphurous anhydride Phosphorus trichloride Arsenious chloride Arsenic Arsenious anhydride 81 9 16 184 22 32 35 62 683 90 71 or 142 . 100 . 150 198 ELECTRICITY AND TELEGRAPHY. HE submarine cable between Lowestoft and fault is calculated to be at a distance of about six- The "Narva," with the Cuba cable, has arrived out at Key West after a quick passage. We are daily expecting to hear news of the successful laying of this cable. owing to the continuation of fine weather, com- present rate of profits, and we are glad to find that THE ROYAL AGRICULTURAL SHOW. munication was restored yesterday morning. the Government have agreed to a satisfactory scale The Government have despatched from Malta of compensation for the staff. The result of the HE arrivals of agricultural machinery and THE agreement has been to increase the value of the implements on the show ground at Leicester one of their surveying vessels to sound the direct shares enormously. The announcement of an agree- have continued with such rapidity as to tax the route between Malta and Alexandria preparatory ment having been come to between the Government powers of the large body of men engaged in reto the submersion of the cable now being manuand some of the leading railway companies, by with-ceiving them. At one time the discharge of railfactured for the Anglo-Mediterranean Telegraph drawing their opposition, will also tend to materially way waggons on the new branch line, which runs shorten the labours of the Committee. The railways close to the show ground, averaged 200 -day. Company by the Telegraph Construction and already agreeing are the Great Northern, North- About 340 stands have been taken by imp ment Maintenance Company at their works at Green-Western, Great Western, Midland and North- manufacturers this year, whilst last year, at Bury wich. The manufacture of the cable is being Eastern, and there is every hope of similar agree- St. Edmunds, only 282 were taken. The Leicester rapidly proceeded with, Mr. Latimer Clark ments being concluded with the South-Western show will therefore be the largest of all previous and Lancashire and Yorkshire Railways. being the superintending engineer for the AngloThe exhibitions of the kind. Ono important feature principal features of the arrangement are that this year in connexion with the shedding is that Mediterranean Company, their own engineer, each company is to have its own system of tele- the machinery in motion will be in a continuous Sir Charles Bright, being absent with the Cuba graphs on railways and canals independent of the line, and the stands opposite to each exhibitor in cable expedition. Post-Office telegraphs, and that the Post-Office are the implement department (the sheddings for which to have a perpetual way leave over railway lines, run in a transverse direction), instead of, as in the railway companies erecting and maintaining all former years, being scattered up and down the wires and poles on the railway, and the Post- show ground. Consequently, the stand for each Office paying for those belonging to them on exhibitor of implements will be in close proximity terms to be agreed upon or settled by arbitration. to his stand for machinery in motion. This arThe question of taking over the submarine rangement will spare visitors a protracted tour of cables of the various companies has not as yet been the yard in quest of any particular stand. But, considered, though we believe, from what Mr. for all this, there will be over four miles of shedScudamore has stated, that it is the intention of the ding. The engines in motion on the ground will Government to purchase them all. number more than 100, and arrangements have been made, by the establishment of a temporary fire-engine station, for promptly staying any outbreak of fire. The implements will be shown in 36 sheds, 23 of them being 300ft. by 50ft., and the remainder 200ft. in length; while the machinery in motion will be comprised in two large sheds of 1,050ft. run by 20ft. to 25ft. wide. eight sheds for seeds and models, 160ft. by 13ft., and 22 for cattle. The following is the arrangement for the ensuing week:-Thursday, July 9, to Wednesday, July 15, trial of ploughs and field implements, and preliminary trial of steam cultivators, on farms belonging to Messrs. Stone and Miles, in the parishes of Knighton and Aylestone, adjoining the Midland Railway, about a mile south of the show yard. Prizes, £255. Admission will be free. The arrangements for the annual county exhibition of the Royal Horticultural Society are also rapidly approaching completion. This will cover five acres, and will be the largest held in the provinces. The Isle of Man Company are having a short length-about eleven miles of cable made for restoring the communication between the island and Whitehaven. The cable consists of some of the old Hague cables, purchased from the Electric and International Telegraph Company, served with hemp, and strengthened with galvanized iron wires of No. 3 gauge. Although it is so long as thirteen and fourteen years since the gutta-percha covered wire in these cables was manufactured, it is wonderful, considering the vicissitudes of the Hague cable, what a capital condition the material is in, showing even now a favourable comparison with present manufactures. This is a fact that speaks highly for the lasting of submarine cables insulated with gutta-percha, and if the material of that date, after such a lapse of years, shows such favourable signs of lasting, what may we expect of the superior manufacture of the present time? The core we are now speaking of was one of the original Hague cables; it reposed at the bottom of the North Sea for many years, when it was picked up and laid with some others across the Irish Channel to Houth, where, after having been of great service, it was picked up and deposited at the company's stores until now. Such are not the most favourable circumstances for preserving the goodness of a cable. This short length is being covered at the Silvertown Works. Active steps have lately been taken with regard to a submarine cable from France to America, and In order to give the Government some opportunity of a working trial, we understand that Mr. N. Holmes has offered to the Post-Office to make a trial between Newcastle and Neubiggen, where wires are being erected for the Danish-NorwegianEnglish Telegraph Company. This will be through the submarine cable now being manufactured by Mr. Newall, and shortly to be submerged. We are not aware at present that the proposal has been accepted. We noticed lately some interesting experiments of M. Carré relative to the light obtained from carbons impregnated with metals; he has since exhibited to the Paris Academy some of his metallic carbon, containing iron, antimony, &c.; on experimenting with these it was found that they gave a light over one-third more powerful than that obtained from ordinary carbon. THE INSTITUTION OF CIVIL ENGINEERS HE council of the Institution Civil -Original communications submitted to the insti- we have to announce that the French Government Telford premium, in books, to George Higgin, M. Mr. W. T. Henley is about commencing at his works at North Woolwich a length of cable of about 300 miles for a Norwegian Company, whose intention it is to submerge it between Peterhead, in Scotland, and Norway. We shall, in the course of the manufacture of this cable, give some details of its construction. The core is now being manufactured at the gutta-percha works at Wharf-road. All the steel wire required for the cable between Malta and Alexandria is being drawn at Mr. Henley's works. The special committee of the House of Commons on the "Electric Telegraphs bill has been sitting almost daily. From the present appearance of matters, their labours are apparently drawing to a close. This has been undoubtedly facilitated by the withdrawal of the opposition on the part of the companies, between whom and the Government negociations have been on foot for some time. These have been brought to a close by the acceptance of certain terms, subject on the one hand to approval by the shareholders, and on the other by the Select Committee. The principal point is that the amount paid is to be twenty years' value at 3. A Telford medal, and a Telford premium, in "On There are CAST STEEL AND WROUGHT-IRON Staining the relative merits of cast steel and OME interesting practical experiments for ascer wrought iron for boiler plates have recently been made at Messrs. F. Harkort and Sons', Harkorter Iron Works, at Schonthal, near Wetter, Westphalia, and the results obtained, as given in the Mining Journal," were decidedly in favour of steel. The two boilers employed were used in connection with the puddling and rolling mills, and were both of the diameter, with dome 2ft. high by 2ft. wide; the thicksame form and size, being cylindrical, 30ft. long, 4ft. ness of the iron plates was a little over 4-10in., and that of the steel plates in., and the respective weights 8,975lb. for the iron, and 5,8421b. for the steel. It was found whilst a pound of coal evaporated 3-201b. of water in the steel boiler, it evaporated only 2.511b. in the iron one. To perform the same amount of work it required in the wroughtiron boiler 28 per cent. more fuel and 30 per cent. more time. The coal used was that from Ruhrort. boilers in use, and one of them, which is made of At the Harkorter Works they have now fifteen steel soft Bessemer steel, has been found to give quite as good results as the others. There was, likewise, a marked diminution in the amount of incrustation in the steel boilers, owing, probably, to the extreme smoothness of the surface; water which gave an incrustation of in. in two years in the wrought-iron boilers, gave in the steel boilers an incrustation scarcely perceptible. THE MONT CENIS RAILWAY TRAFFIC ARRANGEMENTS. THE meeting of railway managers and engineers the benefits of irrigation in India; and on the mental determination of the strains on the suspen sion ties of a bowstring girder." 12. The Manby |