The circumstances which have determined the Eastern River boats are, a limited draught of 8 feet, an enormous traffic in passengers and goods, and a journey of 150 miles, to be performed at great speed during the night. We must therefore consider the ship subordinate to the house which it carries. The dimensions of these boats are, 300 ft. long, 35 feet beam, 10 feet deep, with a draught of 6 feet. The hold of the ship is not used for cargo, but it is a huge barrack lined from end to end with three or four tiers of berths. The deck extends beyond the side of the ship at least 15 feet. The boilers are carried outside the ship on this platform or guard, here the engines are worked, and the cargo is piled up all round. On the next deck is the grand saloon, on each side of which there is a line of state rooms, each containing two berths. This saloon is handsomely decorated, being first class accommodation. As the whole cargo, machinery, and boilers are in the middle of the ship, there is a tendency to sagg or sink at that part. The American builder corrects this by the hog frame or large trussed girder, extending to within 50 feet of either end, which thus supports the excess of weight in the middle, by the excess of buoyancy towards the two ends. To equalise the weight, however, still more, short masts are set up, and by guys carry up any excess of weight. Two of these are set up at the boilers, and really transfer their weight through the guys and the masts to the bottom of the ship. The engines of these boats are the old beam engine of James Watt, with wooden frames, and such other changes as are necessary for their application as marine engines. The comparison of the Eastern waters and the Eastern steam-boats present us with a striking contrast to the Western. The Mississippi and its tributaries are nobler waters than the Hudson, and the traffic is even greater. But there is a peculiarity in the navigation of the Mississippi, which is the cause of the main points of difference, and which probably does not exist anywhere else. These peculiarities arise from trees, which fall into the water through the washing away of the banks of the river, and take, according to their characters, the respective names of planters, sawyers, and snags. From these arise the extraordinary economy of the cost of the western boats. Vessels, sure to be lost, must be cheap. So flimsy indeed are they, that the natural life of a Mississippi boat is only from six to seven years, and there are not many that reach that advanced age, being generally burnt, burst, or snagged, in their comparative infancy. The dimensions of the larger western boats are 250 feet long, 40 feet beam, and 8 feet deep, and a draught of 4 feet. The hull of these ships is strengthened by 3 longitudinal bulkheads running the entire length, and it is occupied by the heavier part of the The discussion upon Mr. W. H. Precce's paper, "On the Maintenance and Durability of Submarine Cables in Shallow Waters," occupied four evenings. It was observed, that during the last two generations there had been three marked events in the engineering world :-Watt's introduction of the steamengine, which gave power; the introduction of railways, which supplied locomotion; and the invention of the electric telegraph, which, as an instantaneous agent for transmitting thought, was fully as important as either of the others. It was explained, that with a view of limiting the paper, it had been impossible to notice the effect of temperature upon wires-a frequent cause of serious error-the defects of stranded wires, testing under water, working damaged wires with single currents, the comparative advantages of screw and paddlewheel steamers in laying and repairing cables, and particularly the improvements in the testing instruments introduced by Messrs. Siemens and Halske, of Berlin. It was thought that the chief points for discussion were, the necessity of thoroughly surveying the route before laying a cable, the important question of the insulating medium, and of applying some exterior protecting coating, not only to cables intended for shallow water, but also for those to be laid in deep seas. The neglect of this latter precaution had, it was believed, been the cause of the recent failures in deep-sea cables, which had been found to be decayed and rotten, when attempted to be lifted for repairs. The cable laid between Toulon and Algiers was believed to be nearly the true form for deep seas, and if combined with the Red Sea cable, the desired form would then almost be produced. When the Channel Islands cable was laid, the electrical condition was considered to be most satisfactory, as the instruments acted with great facility and with very low battery power. The selection of the route was not left entirely in the hands of the contractors, but was determined in concert with a government department. The shore ends of cables had generally been made too light, and in some cases, where rivers or bays had to be crossed, the plan had been adopted of laying the cable in a succession of tubes, connected together by universal joints. One of the principal causes of the failure of telegraph cables was their not being thoroughly tested under water until they were deposited in the ocean. When the Red Sea telegraph was laid, it proved, like most lines just completed, very successful. It was stated to have been worked from Alexandria to Aden, at the rate of ten words per minute, with double relay stations at Kossier and Suakin. There were a few embryo faults, but it was thought that it might have been worked successfully for a considerable time, if a permanent system of daily tests and of timely repairs had been established. There were other destroying agencies besides those which had been alluded to, such as excessive tropical heat, and the effect upon the cable of metallic veins at the bottom. The sections of the Red Sea cable had lasted altogether for nine months before the first fault occurred, having only given way the day before the Indian extension was completed. With regard to the government cable to be laid from Rangoon to Singapore, an opportunity had been afforded of carrying out a complete system of testing from the first. The old system was to test by the galvanometer, and to judge the condition of the line by the angle of deflection and the battery power employed. This was not deemed satisfactory, for reasons which were explained; and instead, the method was adopted of comparing resistances. First, a constant unit of resistance had to be established, and the Messrs. Siemens used for that purpose the resistance of a column of pure mercury one metre in length and one millimetre in sectional area. This had the advantage of being easily reproduced, and was thought preferable to the plan adopted by the author, of taking the resistance of one mile of No. 16 copper wire, as the copper of commerce had been proved to vary in its conductivity between the limits of 100 and 7. Coils of resistance were next formed of German silver wire representing, respectively, units, tens, hundreds, thousands, and tens of thousands of units of resistance. By introducing these variable resistances into the three sides of a Wheatstone's Bridge, or Electric Balance, the resistance of the fourth side, which was the gutta percha, or copper conducter of the cable under examination, could be ascertained with the utmost certainty, the limit of error not exceeding practically one in one thousand. Another feature of this method was, that the time during which the electric current was allowed to act, before discovered, that inductive tension followed the same the observation was taken, was noticed. It had been simple law of Ohm as the electric current itself, in passing from the conductor through the insulated covering, and admitted, therefore, of being subjected to the same precise methods of measurement. Although this system of testing cables had not been long in use, yet resistance coils had been employed for determining the position of faults in subterranean lines ever since the year 1849. In the case of the Rangoon cable, a complete record was obtained of the copper and gutta percha resistances of cach mile of cable, so that when the core was joined together, it was possible to detect the slightest defect, which, if allowed to pass, might afterwards develope itself into a fault. Moreover, in laying the cable, or afterwards, any decrease of the insulation was at once known. It had been originally intended that the Rangoon cable should never leave the water, that it should be kept in tanks during the process of manufacture, and be payed out from tanks into the sea. As, however, the tanks could not bear the great pressure, the cable became exposed to atmospheric influences. It was soon observed that there was a decrease of insulation, indicating a considerable increase of temperature. Subsequently this became so great, that it was necessary to test the temperature of the coil of cable in every part. For this purpose a peculiar thermometer was used, constructed upon the principle of the resistance of copper wire to the electric current, or tube of metal. In coiling the cable on board, several of these thermometers were inserted at different layers of the coil. When tested, after being on board only one week, it was discovered that a spontaneous generation of heat had taken place, and that the heat developed itself unequally throughout the mass, the highest temperature being about 3 feet below the upper surface of the coil. A large quantity of water, at a temperature of 42° Fahrenheit, was poured upon the cable, and this was observed to issue from the bottom of the hold at 72° Fahrenheit. This occurrence seemed to show that other cables, more particularly the Atlantic cable, which had been coiled on board wet, might have been ruined from the same cause. If the heating had been allowed to continue a few days longer, the gutta percha would have been softened, and the copper conductor would have become eccentric to the insulating material. It was considered probable that this generation of heat was due to fermentation of the hemp covering, whilst it had also been attributed simply to the rusting of the iron. With regard to the construction of cables, it was considered that a metallic covering must be adopted, as there were cases where hemp-covered cables had been completely destroyed by marine animals; but that the external iron covering should be protected against the action of the water. In reference to the insulating material, gutta percha had several disadvantages. It was readily softened by heat, was liable to contain cavities, and was affected chemically by every current that passed into it. India rubber possessed a much higher resistance to electricity; and certain compounds of that material had also valuable properties. It was admitted that the only depths considered to be of primary consequence in the early nautical surveys were those under seven fathoms, the depth at which a large line-of-battle ship might strike the bottom. It was maintained that iron should never be employed as a covering for submarine cables. Such a defence should be composed of copper, or of some metal, or other substance, that would not oxydize, and would receive a gradual submarine deposit of a calcareous nature, affording a permanent protection against damage or decay. But, as far as experience had shown, it appeared that in the deep ocean scarcely more than the insulating covering was generally required. It was remarked that submarine cables for shallow waters might be comprised under four classes:1, The hempen cable; 2, Galvanised iron cable; 3, Unprotected iron cable; and 4, Iron cable with some protecting covering. With respect to the first, there were mechanical defects sufficient to condemn its use, as the action of abrasion against the tide and rocks would cause it to be destroyed in a few days. On the other hand, galvanised iron cables, of which there were many hundred miles laid from the English coast, seemed to be very durable, when buried in mud or sand; but wherever they were exposed to the free action of the tide, corrosion commenced. They, however, possessed a durability of about three years beyond unprotected iron cables; but after that time the zinc generally disappeared, and all cables were alike acted upon by the sea-water, whether originally galvanised or not. This corrosion was conjectured to result from the cable lying upon protruding veins of copper ore, or other material which was electronegative with respect to iron. The first cable laid between Hurst Castle and the Isle of Wight, five or six years since, became so deeply corroded in eighteen months that it was broken by a ship's anchor. This was replaced by a smaller cable, which did not last a year, and subsequently by a third of stronger construction, and that was now being superseded by a fourth cable. Therefore, three, cables had been already destroyed, partly by ships' anchors and partly by corrosion. It was believed that sea-water alone was not sufficient to produce this destructive action upon iron. A cable laid from Whitehaven to the Isle of Man was coated with a serving of jute saturated with common asphalte. The process was inexpensive, and appeared calculated to last for an indefinite period. The failures of the Atlantic and of the Red Sea cables certainly demanded most serious consideration. That some mischance should happen to the Atlantic cable was not surprising, when the limited experience then obtained in submarine telegraphy in deep water was taken into account. But in the case of the Red Sea cable, there was no excuse for using unprotected iron wire scarcely larger than bell wire for the covering, as there had then been abundant experience to prove that after being only a few months in the sea it would become so rusted that should any repairs be necessary it would not be possible to lift the cable to the surface. Similarly, the cable about to be sent to Rangoon would not be fit for use for more than three or four years, under the most favourable circumstances; and if repairs were required, the cable would be found to be so much decayed, that it would not be able to be raised. It was to be regretted that a cable designed to be laid from Falmouth to Gibraltar should have its destination changed to a much warmer climate, because the electrical conductivity of guttapercha was greatly increased, or its insulation was impaired by heat. In reference to the Red Sea telegraph, it was remarked that before the form of cable was determined upon, a specimen of the cable proposed to be adopted was submitted to several eminent scientific men, who generally concurred in the propriety of using it, and on no occasion were the directors dissuaded from having a cable covered with iron wire. In reply it was argued, that at the time the Red Sea cable was designed, so many instances had oc curred of the oxidation of the iron covering of cables, and their decay was so much a matter of notoriety, that provision ought to have been made to protect the iron from the destructive action of the sea-water. In selecting a route for submarine telegraph lines, it was thought that deep water should be avoided, wherever that was possible, even if a considerable detour had to be made. In a depth of 100 fathoms, a cable was beyond the reach of attrition, and was as little likely to be injured as when laid at a depth of 200 or 300 fathoms; whilst it could be repaired almost as easily as if it lay in water 30 or 40 fathoms deep. The nature of the bottom was most important, as where rough ground and rocks existed the cable could not be grappled. To ascertain this correctly, the use of the sounding lead alone was not sufficient; a mushroom anchor, which would bring up a bucketful of the surface material, and occasionally deep-pronged grapnels, ought to be employed. The line should be divided into short sections, of say 100 miles in length; for although it might be possible to "work" through 500 or 1,000 miles, yet when one section was damaged the consequences were more serious. It was believed that the Red Sea and Indian telegraph cables might have been laid where they could easily have been grappled, and lifted for repairs; and that in the line from Suez to India, there would not have been any difficulty in dividing it into sections of 50 miles each, throughout nearly the whole distance. Normandy, although not much larger in dimensions | genou, about fifty blows being given. The density of It was stated, that the Red Sea telegraph was divided into six sections-three in the Red Sea, Suez to Kossier, 254 knots, Kossier to Suakin, 475 knots, and Suakin to Aden, 630 knots, or in all 1,359 knots of direct distance; and three in the Indian Ocean, Aden to the Kooria-Mooria Islands, 716 knots, Kooria-Mooria to Muscat 486 knots, and Muscat to Kurrachee, 481 knots, or in all 1,683 knots, making the total length of the two lines 3,042 knots." Messages had been transmitted between Suez and Aden for about nine months, and separate sections of this line had been worked for eighteen months. It was also mentioned that the line had been worked from Aden to Kurrachee, by means of translation, at very good speed; but that the whole distance from Suez to Kurrachee had never been worked throughout. The cable had been underrun and examined for many hundred miles, and it certainly was not corroded to the extent which might be imagined. As a general rule, the strength of the cable had not been diminished one-tenth by corrosion, after being submerged a year. (To be continued in our next.) MANCHESTER LITERARY AND PHILOSO PHICAL SOCIETY. LUMINOUS ENVELOPE OF THE SUN. Mr. Nasmyth has made the discovery that the entire surface of the sun is composed of objects of the shape of a willow leaf; these objects average about 1,000 miles in length, and 100 in breadth, and cross each other in all directions, forming a network; the thickness of this does not appear to be very great, as through the interstices the dark or penumbral stratum is seen, and it is this which gives to the sun that peculiar mottled leaf-shaped objects are best seen at the edges of a appearance so familiar to observers. These willowsolar "spot, where they appear luminous on a dark ground, and also compose the bridges which are With regard to the durability and maintenance of formed across a spot" when it is mending up; the shoal-water cables, it was remarked that there were only approach to symmetrical arrangement is in the two schools of engineers, one adopting comparatively filaments bordering the spot, and those composing light cables, the other laying them as heavy as possible. The earliest submarine cables, between Dover stratum of the sun's luminous atmosphere: here the penumbra, which appears to be a true secondary and Calais, Dover and Ostend, the Magnetic Com- these bodies show a tendency to a radial arrangement. pany's lines to Ireland, as well as several others, were Although carefully watched for, no trace of a spiral or all strong cables, containing several conducting wires, vortical arrangement has been observed in these filacovered with a thick serving of hemp, and over allments; thus setting aside the likelihood of any whirl. massive iron wires of large gauge. These had been wind-like action being an agent in the formation of singularly fortunate. It was true that some of them the spots, as has been conjectured to be the case. The had been injured by ships' anchors, but those occurwriter does not feel warranted at present in hazarding rences were rare, and the cables never suffered from any conjectures as to the nature and functions of "abrasion," or from being "washed away by the sea," these remarkable willow-leaf-shaped objects, but incauses which seemed to have been so fatal to the tends pursuing the investigation of the subject this Channel Islands telegraph. The new system of laying light cables in shoal water was first adopted by the tish Association during their meeting in this city. summer, and hopes to lay the results before the BriElectric Telegraph Company, in their lines from The paper was illustrated by three beautiful drawings. Orfordness to the Hague, where, instead of laying one strong heavy iron cable, four comparatively light No. 2 the luminous surface of the sun as being entirely No. 1 represented one of the willow-leaf-shaped objects; cables, each with one conductor only, were laid across composed of these objects; and No. 3 a large drawing the North Sea, on the principle that the chances were of a solar spot as seen on the 20th of July, 1860, exagainst all the four being broken at the same time. hibiting the surface of the sun composed of these That experiment, which had also been adopted by the objects, as also the penumbra and the bridges across same company between Dublin and Holyhead, could the dark portion of the spot in which the exact shapes not apparently have been satisfactory, judging from of these objects were to be seen most clearly. the high annual cost stated for repairs, and from the fact that a heavy cable had been recently laid by that company from Dunwich to Zandvoort, in Holland. A somewhat similar plan had been pursued in the Channel Islands and the Red Sea lines, for the latter was laid to a great extent in shoal water. With these exceptions all the shoal-water lines had been strong cables, and there were many in existence in different parts of the world, which had never required the most trifling expenditure for repairs since the date of their submersion. Two of these belonging to the Magnetic Company, were necessarily laid on a rocky bottom, subject to the action of strong currents, but they were laid with sufficient slack to meet any irregularities in the bed of the sea. The heavy cables laid 1854, between Spezia and Corsica, and across the Straits of Bonifacio, passing over depths of between 700 and 800 fathoms, and crossing several coral reefs, had worked well and continuously. The Submarine Company's line from St. Catherine's, in Jersey, to Pirhou, on the coast of Mr. Sidebotham stated that the image of the sun was examined by Mr. Nasmyth with a mirror of plane glass set at an angle of 45 degrees; nearly the whole of the light and heat of the sun passed through the glass, and the rays used were those only reflected from its surface. ROLLED COPPER. Mr. Charles O'Neill read a paper "On Changes of Density which take place in Rolled Copper by Hammering and Annealing." The results of his experiments proved that the best commercial rolled copper actually lost density by hammering instead of gaining as might have been anticipated. In the first series of experiments ten pieces of copper were cut from a sheet of the thickness of inch, the pieces weighed from 250 to 320 grains each, their mean density was 8.879. The pieces were then separately subjected to the action of a powerful compressing machine acting on the principle of the The author considered there was a connection between these phenomena and the heat disengaged in the hammering of the copper; he conceived it possible that the expanded state of the copper while heated by hammering was retained, and that the effect of annealing might be to allow the molecules or particles to recover the state in which they were in before being disturbed by the heat produced in hammering. GEOLOGICAL SOCIETY OF LONDON. March 6.-L. Horner, Esq., President, in the chair. Francis George Shirecliffe Parker, Lieut. H.M. 54th Regt., Roorkee, and J. Gwyn Jeffreys, Esq., were elected Fellows. Papers on the following subjects were read:1. "On the Succession of Beds in the Hastings Sand in the Northern portion of the Wealden Area." By F. Drew, Esq., F.G.S. of the Geological Survey of South of Yorkshire; and on their Paleontological Relations." By J. W. Kirkby, Esq. Communicated by T. Davidson, Esq., F.G.S. Great Britain. 2. "On the Permian Rocks of the MEETINGS FOR THE WEEK. Mox.-London Inst., "On the Progress and Power of British Architects, "On Saracenic Architecture," TUES.-Inst. Civil Engineers, Discussion upon Mr. THURS.-Royal Soc., at 8:30 p.m. Soc. of Antiquaries, at 8.30 p.m. Royal Inst., " Electricity," at 3 p.m. FRI.-United Service Inst., "Lifeboats," by Capt. Ward, R.N., at 3 p.m. Royal Inst., "Inorganic Chemistry, by Dr. E. The Times, in speaking of Ward's Marine Signals, Woolwich, of the new Admiralty night signals, in says, the first delivery was received yesterday, at vented by Mr. W. H. Ward, and manufactured by Messrs. Ridsdale. The inventor has succeeded in embodying in these signals (the system of which is now adopted by the British and other navies), the whole of the improvements which have been sug gested from time to time by the authorities of Woolwich-dockyard in their investigations during the last 18 months, as well as by the Lords of the Admiralty themselves at their various inspections of the invention during the progressive stages of improvement. The system now presents an entirely new feature, the dimensions, weight, and efficacy of the apparatus having been totally changed. The whole of the sets delivered yesterday having been inspected by the authorities, were readily approved and stored for transport, being intended for the first division of the Channel fleet, in command of Rear-Admiral Smart. WEBSTER'S IMPROVEMENTS IN THE MANUFACTURE OF PRUSSIAN BLUE. VALLANCE'S TELESCOPIC SIGHTS FOR RIFLES. &c. MR. VALLANCE, of St. John's Wood, has just patented some improvements in the construction of telescopic sights for rifles and other fire-arms and ordnance, which consist in employing a telescope arranged without any body or tube, the lenses being simply placed at a suitable distance the one from the other, and the space between them unen- rifle shown. A No. 4 spectacle lens for short | NORMANDY'S IMPROVEMENTS IN CONclosed. By this means the advantages of a teles-sight is suitable; the same will also do well for a copic sight are attained without the inconveniences resulting from any material increase of weight and complication of parts. The invention also consists in combining with a rifle or other fire-arm, or with a piece of ordnance, a telescope on the Galilean principle, and having cross wires or other suitable sighting points near the object glass of the telescope. The arrangement the patentee prefers is this :-He employs as a foresight a tube or frame containing cross wires, and immediately behind the wires he places a convex lens. For the back sight of the telescope a plate or disc is employed, having a small perforation in it through which the sight is taken, and so arranges the plate or disc that the perforation can be adjusted in position to give the requisite elevation for different ranges. Near or on this perforated disc a concave lens is placed, so as in combination with the lens of the foresight to form a Galilean telescope. On looking through the perforated disc the cross wires of the foresight will be clearly seen, and their point of intersection may be made to cover any object which appears in the field of view of the telescope. The annexed engraving illustrates the fore. going-a is a short tube attached to the muzzle of the rifle; b is a dovetail attached to the tube, and which entering a corresponding notch in the muzzle of the barrel sustains and holds the tube in its proper position; c is a magnifying lens, the focal length of the lens should be for a long Enfield rifle 48 inches; cross wires are placed in the tube immediately in front of the lens, or in place of these cross wires the ordinary sight may be employed. The tube a in this case not carry ing the cross wires, but being arranged so that the lens may come immediately behind or before the foresight of the rifle. d is the back or elevating sight of the rifle, this is screwed into the stock and caused to project a greater or less distance from the stock according as the range at which it is desired to shoot is long or short; the stem of the sight being graduated it is easy (by turning it in one or other direction) to bring it to the elevation required for any given length of range. There is a small perforation in it, through which the sight is taken in aiming. This hole is made as small as it can be made to allow a sufficient amount of light to pass to the eye. Immediately behind this aperture a concave lens is placed, of the power requisite to produce clear vision for the long Enfield rifle. In the arrangement shown, the back or elevating sight is shown fitted with two lenses; they are mounted on arms which turn about a centre, so that one or other of the lenses, as desired, can be brought opposite the aperture. The object of thus employing two lenses is, that they may be made of somewhat different focal lengths, and then the person using the piece will select the lens which he finds best suited to his sight. Sights similarly constructed are suitable for other fire-arms and for ordnance. WEBSTER'S IMPROVEMENTS IN THE MANUFACTURE OF PRUSSIATE OF AMONG the chemical patents recently granted is one to Mr. J. Webster, of Birmingham, for "improvements in the manufacture of prussiate of potash and prussian blue," which consists, first, in causing oxide of iron or iron in other like state to enter into combination with bark, wood, sawdust, or spent bark (that has been used by tanners); this combination of the vegetable with the mineral substance is formed by simply mixing the two together and applying moisture. After the combination is formed the whole is dried and burned in the retorts, illustrated in the accompanying engraving. When cold it is saturated with carbonate of potash as in the usual way of manufacturing. And, secondly, in using sulphate of ammonia with lime and water in a suitable boiler for making and supplying ammoniacal gas to the whilst in a hot state, and charged with iron and carbonised bark, wood, sawdust, or spent bark, potash, the prepared bark being at the time confined in the retorts. The arrows show the passage of the ammoniacal gas which enters the retorts at a, and the gas not taken up by the contents of the first retort passes into the second, and so on. The superfluous gas finds its way into the condenser, which is filled with moist coke or other rose b at the top; the gas meeting with the damp like substance, and is kept moist by the water substance is condensed, and falling, passes into the tank, and is then ready to form more gas by being mixed with lime. In the Pacific Mills, Lawrence, Mass., one of the machines for printing delaines stamps the picce with sirteen different colours and shades of colour in passing through once! NECTING GAS AND OTHER PIPES. MR. A. NORMANDY, of Clapham-park, has recently patented a very useful "improvement in connecting gas and other pipes." The pipes are plain from end to end, that is to say, without sockets, and when two such pipes are laid end to end, the inventor slips over them a short cylinder of slightly larger diameter. This cylinder is made with sockets or recesses of larger it has also flanges at its ends. Into the sockets or diameter than the other parts of the cylinder; and recesses rings of vulcanized india-rubber or other suitable packings are introduced, and over these filling pieces or rings of metal are placed which These filling pieces are enter the sockets. furnished with flanges, by means of which the said pieces are forced down upon the packing, screw bolts being employed to draw the flanges cylinder; other means may be employed for on the filling pieces up to the flanges on the forcing the filling pieces or rings on to the packing, or other means of expanding the packing and pressing it firmly in contact both with the pipes and the covering cylinder may be resorted to. The accompanying engraving shows a longitudinal section, and a plan of the ends of two pipes connected together in the manner above des cribed. HEDLEY'S IMPROVEMENTS IN OBTAINING MOTIVE POWER, &c. MR. HEDLEY, of Newcastle upon-Tyne, has just completed a patent for improvements in obtaining motive power and in evaporating liquids. For these purposes the inventor takes the exhaust steam from a steam engine; and heats air to as high a temperature as the steam will raise it, and this is done by causing the air to pass through channels or passages heated externally by the steam, or the steam may be otherwise applied to heat the air. He then, by means of a forcing apparatus, compresses this heated air until it is raised to a high pressure and temperature, and the air so heated is applied to evaporate water in a boiler, in order to generate steam, which is then worked in a steam engine in the usual manner. Air so heated and compressed may also be applied to evaporate liquids where it is not required to generate steam for working a steam-engine. The annexed engraving represents a longitudinal section of machinery, arranged and combined according to this invention. a is a chamber into which atmospheric air may freely enter at the opening b, which is shown to be covered with a valve, which, however, when the engine is at work, may be kept constantly open; ce are a series of tubes within a vessel d d, into which steam is constantly supplied, and such steam is, by preference, exhaust steam from a steam-engine. The water resulting from the condensation of steam is run off at the bottom of the vessel by the ordinary well known apparatus, or it may be used as feed water. The air thus or otherwise heated is received into the vessel or chamber e e, from which it passes into the cylinder f, either above or below the piston g, according to the direction in which the piston g is being moved. The valves h and i open and close as the piston changes the direction of its motion. The piston g is actuated by a steam-engine, and, by preference, worked by the steam generated in the steam-boiler m, or other suitable motive power may be employed for ac tuating the piston. The air received into the cylinder f is alternately forced out therefrom through the passages, which are respectively closed by the valves j and k, into and through KLINTIN'S IMPROVEMENTS IN SHIPS' LOGS. the tubes 77 in the steam-boiler m, and thence into the receiver n at the further end of the air be compressed to any desired extent, and the steam-boiler; and in this manner may the heated heat thereof largely increased. The heated air thus compressed in the chamber and tubes of the steam-boiler will give off some of its heat to the water in the boiler, and generate steam to be used for actuating a steam-engine, or the steam thus place of a steam-boiler m being employed, another generated may be used for other purposes; or in vessel suitable for evaporating fluids may be used. The heated and compressed air in the receiver n is allowed to pass therefrom to work an engine of any suitable form and construction for being actuated by heated and compressed air, as is well understood. By thus combining machinery, atmospheric air will be heated, then compressed so as to occupy less space, and consequently become of higher temperature and suitable for evaporating water or other fluids. MR. J. F. KLINTIN, of Stockholm, has just completed a patent for a very simple and useful "improvement in ships' logs," which consists of a tube having curved blades on the exterior to cause the tube to rotate when drawn through the water. One end of the tube is permanently closed, and is fitted with a universal joint, by which it may be connected to a line, and the other end is fitted with a water-tight cover. Within the tube is placed the recording apparatus, containing wheelwork, which gives motion to the hands of three or more dials, the second dial indicating ten times as many revolutions as the first dial, and the third ten times as many as the second, and so on. The wheelwork is provided with a spring, which presses against the interior of the outer tube, so that when the FIG. 1. FIG. 2. round with it. The train of wheels of the recordtube rotates the recording apparatus is carried ing apparatus is set in motion by the last wheel gearing with a worm, on the axis of which there is an arm carrying a weight; this weight, when the exterior tube is rotated by being drawn through the water, prevents the worm from being rotated with it, and the other wheels being car ried round it are thus caused to rotate on their own axes. Before using the apparatus the cover is removed from the end of the exterier tube and the recording apparatus is taken out and the pointers of all the dials set at zero. The apparatus is then inserted into the tube and the cover replaced, when the apparatus is ready for After use the number of revolutions the exterior tube has made may be ascertained by removing the cover from its end and taking out the recording apparatus, the dials of which will show the number of revolutions made. use. Fig. 1 shows a side view; a is a tube having projecting from it four inclined blades bb; the front end of the tube a is permanently closed, and is of a pointed form. To this end a ring c is connected by a universal joint, and by this ring the apparatus is connected to the end of a line. The other end of the tube a is closed by a cover d which fits water-tight, so that the recording apparatus within the tube is kept perfectly dry. Fig. 2 is a plan of the recording apparatus showing the dials, and e is the exterior case of this apparatus; at one end of the case is a wormf, on the axis of which there is an arm carrying a weight f'; the worm f gears with a worm wheel g, on the axis of which there is a pinion which, when the worm wheel is rotated, transmits the movement to the train of wheels which give motion to the pointers hh, which together indicate on their respective dials the number of revolutions made. The dials may be divided in any suitable manner. At the opposite end of the case of the recording apparatus to that at which the weight is situated, is a handle j, by which the recording apparatus may be withdrawn from the tube. Length extreme, about....................................... Depth from Spar Deck,............. 380 414 6,173 She has been constructed to carry 40 guns, 34 of which are to be placed on the lower, and 6 on the upper deck. It is supposed that the vessel will be mounted with 68-pounder long range guns, but it is probable that ultimately Armstrong 100-pounders, or rifled guns will be introduced. About 213 feet of each side of the vessel is rendered invulnerable by shot or shell, by armourplates of wrought iron, from 15 to 16 feet long, 3 to 4 broad, and 44 inches thick, each averaging upwards of 4 tons. In order to deaden the effect of shot, 18 inches of Indian teak wood are interposed between the armour and the "skin," or really water-tight iron shell of the vessel. The teak is of two thicknesses, of 10 and 8 inches-the former being laid with the length-way of the plank, running fore and aft, and the other layer of 8 inches being placed vertically. This sheathing of iron and wood extends from a little above the gunwale to about 5 feet below the water-line. The armour-sheathed space is pierced on the main or gun-deck with thirteen port-holes on each side for 26 guns. These ports are contracted to about two feet, in consequence of the carriage being so constructed that the gun pivots round a point near the outer edge of the port. It is expected that the armament will consist of 34 68pounders on the main or gun-deck, 2 68-pounders, pivot guns, and 4 40-pounders, Armstrong guns. The central armour-clad space and the bottom of the ship are divided into water-tight compartments in order to keep the vessel afloat if seriously damaged, and by this means any damage to the exterior plating, and the flooding arising from it, will be merely local. The mast and rigging of an 80-gun ship, at present in the Royal George Dock yard, are to be applied to the fitting of the Black Prince. The engines, although they are nominally only 1,250 H.P., yet they may be wrought up to about 4,000 or 5,000. It is expected that the vessel will attain the speed of 14 or 15 knots an hour. and The moulded depth of the vessel is 41 feet. The armour-plates cover 22 feet in depth of the topsides, 16 of which will be exposed above the water-line, the armour thus descending about 6 feet below the surface of the water. The intention of Government originally was that the vessel should be a steam ram, for the purpose of running down an enemy's vessel, and it was accordingly constructed with a stem of dimensions strength commensurate with the work it was designed to accomplish. But the stem might be shattered by the collision, or it might be completely blown away, and so might the stern, which is not protected with armour. But even should the stem and stern be blown to shatters, a new stem and stern are lying ready-made underneath. The keel of the vessel is placed internally, where it forms one of an extensive set of girders which run fore and aft, and between these deep floor-plates are introduced, to the lower edge of which and to the girders the plating of the bottom 1846, he made and consumed in lamps oil from is attached. The frames which consist of 10-inch coal, and delivered lectures upon his discoveries in plates and angle irons, are riveted to the inside Prince Edward's Island, Halifax, and Nova Scotia. cage of the floors, and a great part of the bottom Since then he has made more than two thousand is then plated over on the inside of these, and experiments in reference to the manufacture and made perfectly water-tight, thus forming a purification of oils distilled from coal, petroleum, double security in case of injury to the bottom and other materials. In 1847, Charles Mansfield from grounding or any other cause. The vessel obtained a Patent in England for the manufacis built in compartments, so that in the event of ture of oil from coal tar, and was, perhaps, the any part receiving damage the damage is con- first to introduce the benzole or atmospheric light. fined to the particular locality. For this purpose But it is to James Young, of Manchester, that the there are strong iron bulkheads running longitudi-world is chiefly indebted for the most important nally from within a few yards of the stern, on each side of the vessel. NEW BOAT-LOWERING APPARATUS. A FURTHER official trial of the system of instantaneously disconnecting boats from their falls, on being lowered from a ship's davit on any sudden emergency, took place on board the steam tender Lucifer at Portsmouth, on Tuesday, in the presence of Rear-Admiral Superintendent Hon. George Grey; Captains Moorman and Coote, of Her Majesty's ships Cossack and Victory; and several other naval officers. The trials took place outside the harbour, and the boat was lowered three times with the most perfect success, so far as the inventor of the system pretends boat at the moment required by the person in charge to go-the instantaneous freeing of the falls from the of her. To obtain this result, the boat is fitted with an iron shaft running along the boat's kelson and connected with an eccentric under the sternsheets; the latter, worked by a small hand lever, throws the shafting forward or aft as may be required. On this shafting, in a line with the boat's falls, are stout claws, or teeth, immediately in front of each of which are stout metal rollers. From the after part with the boats thwarts. The lower block of each fall of each roller run three-inch square casings, level has its hook prolonged into a stout bar, sufficient to reach the shafting in the bottom of the boat, and terminating in a simicircular link moving upon a stout iron pin. To hoist the boat up to the davits from alongside the bars attached to each block are passed down the casings until the semicircular links by the hand of the man in charge of the boat, the touch the bottom, when the lever, thrown forward claws of the shafting catch the links and jamming each under its roller, it is locked by the eccentric in that position. A pin inserted abaft adds to its security. It will therefore be seen that to lower the boat, the falls having been cleared in the usual manner, and the crew having taken their seats, the lowering from the ship commences in the common way. The officer in charge of the boat, with his hand on the lever, has the power of freeing the boat from releasing both ends of the boat at the same instant. its falls at any moment he sees a fit opportunity, and In this certainly consists the merit of the invention claimed by the inventor, who does not prefer any claims to give the boat headway prior to clearing the ship, as in Clifford's plan. The invention is of a somewhat analogous character to the late Captain very similar character to those adapted for a like Kynaston's, whose disengaging hooks were also of a purpose, in 1833, by Lieut. Waghorn, the projector of the overland route, and which were fitted to the Levant, merchant steamer, and tested in Falmouth Harbour in the following year, in the presence of Captain King, Superintendent of Packets, with the most perfect success. The system of lowering tried on Tuesday, however, professed to be, and certainly appears so, a more certain and instantaneous method than either Kynaston's or Waghorn's. Webb, the inventor, is a carpenter's mate on board Her Majesty's ship Illustrious.-Hampshire Telegraph. Literature. A Practical Treatise on Coal, Petroleum, and other Distilled Oils. By ABRAHAM GESNER, M.D., F.G.S., &c. New York: Bailliere, Brothers. London: II. Bailliere, 219 Regent-street, 1861. THE extensive use of paraffine oil in this country during the past ten years, and the late extraordinary discoveries of mineral oils in the United States have naturally attracted great attention to the history, nature, production, and value of these substances. The volume now before us contains the most complete and reliable information, on this subject which has yet been published. Its author has evidently studied the subject carefully, and has had much experience in the manufacture of the oils referred to. So long ago as August, improvement that has been made in the manufacture of oil from coal. On October 7th, 1850, he secured a patent in England for the obtaining of paraffine oil from bituminous coals. Others in England and America have followed in the same path of improvement, and lately the discoveries of apparently inexhaustible deposits of coal oil in 63,000 square miles, have made this substance an some portions of the United States, amounting to article of immense value to the world. This treatise is, therefore, well timed, and the survey of the discoveries of coal oils and the descriptions of the various kinds of coal from which they are obtained, the modes of obtaining them, their varieties, their impurities, and the methods of purifying them, all of which topics are ably thousands who use these oils daily. For full infortreated in this work, must be interesting to mation, however, we must refer our readers to the volume itself. An epitome of its contents or extracts from it would not convey a correct idea of its great value. But the public are already so deeply interested in the subject that Dr. Gesner's excellent treatise scarcely needs any recommendation to secure for it a wide circulation. -- The Builders' and Contractors' Price-Book for 1861. Revised by GEORGE R. BURNELL, C.E., &c. London: Lockwood and Co., Stationers'-hallcourt, E.C. alterations have been made which add to the value of the original edition. The prices for day-work have been revised throughout, the prices of terrometallic goods have been omitted, the detailed prices of carpenters' and joiners' work have been revised and altered, also the prices of ironmongery, masons' work, and gasfitters' work have been revised, and the text has been condensed. These additions and improvements have greatly increased the value of the work, and it appears to be made as nearly correct as it could be under the circumstances. The arrangement and printing are excellent. In all respects, it seems well adapted to meet the wants of builders or contractors and their workmen. We hope it may be and employed in all the different trades to which useful in preventing disputes between employers it refers. We cordially recommend its use especially in all cases of misunderstanding, or where no fixed prices have been or can be agreed to before work has been commenced. IN this edition of the Builders' Price-Book several A Treatise on Rivers and Torrents, with the Method of Regulating their Course and Channels. By PAUL FRISI, Professor at Milan, F. R. S. of London. To which is added An Essay on Navigable Canals. Translated by Major-General JOHN GARSTIN, of the Bengal Engineers. London: John Weale, 59 High Holborn. 1861. THE engineers of Great Britain are deeply indebted to Mr. Weale for the republication of this volume, and works of a similar class. The first edition of this Treatise on Rivers and Torrents was published at Lucca in 1762, and it must be interesting to those now engaged in the management of our canals, the drainage of our land, the navigation of our rivers, their sources, floods, velocities, slopes, and deposits of sand and mud, to compare their knowledge of these subjects with that of the chief engineer of North Italy in the last century. After the lapse of 100 years, the work of the Professor of Mathematics at Milan will still repay perusal. Its intrinsic merit, its cheapness, and the care with which it is edited, are its highest recommendations to public favour. |