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strengths of current employed. Since, how- wires, a different deflection was obtained in ever, the increase of magnetism from the sec- each case, but these were rendered equal by ond last to the last observation, in cobalt, was inserting an additional resistance in circuit much greater than in nickel, it is not impos- with that wire whose elongation was greater. sible that, with very strong electric currents, The tube was now filled with water so as to the magnetism of cobalt may be greater than carry off the heat generated in the lower wire that of nickel. Unlike the nickel, the cobalt as rapidly as possible. It was found that the piece was not without coercive force.

galvanic expansion was only 1.2 to 2.2 per Ner Electro-Motor. - In a new electro- cent. of the heat-expansion; and no connecmotor recently exhibited in London by its tion was recognizable with the nature of the inventor, Chutaux, the primary force is sup- metal employed. If it be considered that plied by a battery of eight or more cells, these values, of course, can only be an upper being a inodification of the Bunsen battery. limit, it will follow, from the smallness of the The elements used are graphite and unamal- effect obtained, that there is no sufficient gamated zinc, and the exciting fluids are sul- ground for the hypothesis of a special expanphuric acid and bichromate of potash in the sion power of the galvanic current. There inner (or graphite) cell, and a solution of acid can hardly be any doubt that the slight expansulphate or bisulphate of potash in the outer sion which the water-inclosed wire still shows (zinc) cell. No material action is exerted on is simply and alone due to the heat remaining the zinc while the battery is at rest, hence the in it. reason for dispensing with the process of amal Magnetic Equivalent of Heat.-In Lamin gamation. Two or more horseshoe electro- and Roger's decisive experiment establishing inagnets, with their poles upward, are worked the production of heat through disappearance by the current, a wheel rotating on an horizon- of magnetism, the soft iron of an electro-magtal axis immediately above and almost touch- net was placed in the reservoir of a large thering them. This wheel is practically formed of mometer of oil of turpentine; on sending an two parallel wheels joined at their circumfer- interrupted current through the spiral, it was ence by a series of soft-iron bars. As soon as observed that the liquid expanded. The conthe current is set up the wheel begins to re- clusion hence drawn was, that during each magvolve, owing to the attraction between the netization a part of the electricity goes into electro-magnets and the iron, the motion being the iron, producing magnetism, and that at the kept up, and rapidly increased, by means of a moment of demagnetization this magnetism is simple automatic current-rererser." The transformed into heat. In further investigatprincipal feature to which the inventor draws ing this subject, Cazin employed three different attention is the construction of the transverse methods of experimentation. In the first, the soft-iron bars, each of which is composed of iron core was inclosed in an hermetically-closed seven thin plates, much being thus gained in vessel filled with petroleum, and surrounded by intensity of magnetization, and consequently in the magnetizing spiral. From the vessel promechanical power. By a series of ingenious ceeded a capillary tube, also containing petrodevices the machine is applied to the working leum, and the changes of level in it were obof pumps, sewing-machines, lathes, etc., as a served when the core was magnetized by an insubstitute for manual or foot labor. It is not terrupted current. But inasmuch as charge of of course in any way intended to supersede level might arise, not from heat-action, but steam, its object being the simple and easy from the expansion of the iron by magnetism, performance of labor of a light description. the following experiment was arranged : The battery is free from smell, and, being very Into the vessel containing the liquid and the iron “constant," will last for a long time without core were introduced some closed glass tubes, which renewal, the trouble involved in starting and displaced a third of the liquid; the vessel was then stopping the machine being practically nil.

closed, and the experiment repeated. If the expan

sion of the iron were the cause of the change of level, Influence of the Electric Current on the this must now be the same as in the experiment Dimensions of Iron.-The change in length of without the glass tubes; if, on the other hand, the a conductor, through which an electric current change of the level were due to the heat produced, is passing, has been measured by Exner, whose it must now be different, for, instead of three volumes method is free from the error caused by the glass were heated by the same quantity of heat.

of liquid, two volumes of liquid and one volume of expansion due to the heat produced by the cur The experiment then revealed a difference, which rent. In making this measurement, two pieces corresponded to the difference of the specific heats of the same wire of nearly equal lengths were and confinements of expansion of petroleum-oil and hung one over the other, and so connected glass. with a battery that the current might be It was thus proved that the discontinuous passed through either. The lower wire was magnetization of an iron core produces heat. passed through a glass which might be filled In another method for demonstrating and with water if desired. The elongation was measuring this heat-effect, the core was an measured by resting the end of the wire on a iron tube, closed at both ends with corks, and lever carrying a mirror whose deflection was inclosing the bulb of a common thermometer. read by a microscope and scale. The current Here, again, there was heat-action when the being passed successively through the two spiral was traversed by an interrupted cur

rent. In the third method a differential ther- vious that this must occur as long as a single mometer was used, consisting of two hollow car remains on the track, or when the circuit iron cores, communicating by a capillary tube is broken by a displaced or broken rail, or any in which was a liquid index: every beat-action other cause. Hence the device may be applied in the one core was followed by an expansion over an entire line, and will indicate the condiof the contained air, and displacement of the tion of every section to a train about to enter index.

on the same. It is not affected by changes of In order to determine the cause of the de- weather. velopment of heat, M. Cazin proceeded as fol ELIO, JOAQUIN, a Spanish general, died in lows:

January, 1876, very much advanced in years. Round the iron core in the petroleum thermometer He was educated for service in the royalist two coils of 48.) turns were passed, one of them being army in Spain, in which he obtained his first in the interrupted magnetizing circuit, while the cominission. During the progress of a stormy other formed a special circuit, which at each turn public career, he served under many governof the interrupting apparatus was closed. The first coil could now induce a current in the second, if ments. In 1860 he commanded a part of the the closures of the two circuits took place at the Carlist insurgents, and during the last Carlist proper times, as might be arranged at will. These War he also acted with Don Carlos, by whom experiments gave tlie greatest development of heat he had been threatened with the loss of his tinually open. The heat was not altered when the command, and with court-martial, on several circuit was closed at closing of the magnetizing cur

occasions. In 1860 he was captured by Queen rent. There is thus no thermal action during the Isabella's forces, and was only saved from variable period of closure. Lastly, the heat was death by the clemency of the Queen. On that smaller when the circuit of the second spiral, dur- occasion, he wrote a letter to the Queen, in ing the opening of the inducing circuit, was closed; it went down as much as the half, " It thus proved which he promised never again to take part in that the production of the magnetic heat takes place any movements against her; but, nevertheless, during the opening of the voltaic circuit; conse he fought in the Carlist War against her son, quently, that it accompanies the disappearance of Don Alfonso. Don Carlos appointed him in magnetism in the core.''

1873 captain-general of the Carlist forces, and The decrease of heat in this last case is ex Minister of War. He conducted the operations plained on the principle of thermo-dynamics. of the Carlist forces against Bilbao, and the The disappearance of the magnetism is the defense of the line of Sommorastra, in 1874, cause of the appearance of a certain quantity and, when the Carlists were repulsed there, of heat. When no circuit is near, in which an he resigned his position, but remained with the induced current can arise, then the whole of army. this heat appears in the core; but, when induc ENGINEERING. The art of engineering tion occurs, a part of the heat appears in the has made great strides in late times, and, with induced circuit, and the rest remains in the the growth of commerce, has been put more

The cessation of the magnetization is and more into requisition to devise and conan operation in which the magnetic energy de- struct shorter and easier avenues of communicreases and is transformed into heat-energy, cation. In all progressive countries gigantic either in the core or in the neighboring masses works are constantly in progress, requiring which are in a position to be the seat of in- millions of outlay and years of labor, while duction phenomena.

still greater undertakings are being seriously Improved Electric Railway-Signal.-A sim- proposed, such as would formerly have been ple and effective application of electricity to considered fond and idle dreams. Among railroad signaling is in use on the Boston, them may be mentioned the connection of the Lowell & Nashua Railroad. The apparatus is Black Sea with the Caspian by a ship-canal; described and illustrated with a woodcut in the the construction of an artificial channel beScientific American. Its principle will be tween the great rivers of Central Africa, so readily understood from what follows: A sin as to make a navigable water-way across the gle-cell Callaud battery is connected to the two continent; the cutting of a passage between rails at one end of a given section of the line the sea and the low bed of the great African (say two miles in length), each section being Desert, by which a great portion of the sandy insulated from adjoining sections. At the other waste would be submerged, and wide districts end of the section the signal has an electro- rendered fertile; the building of a great shipmagnet similarly connected to the two rails. canal through Southern France from the bay When the circuit is closed, as is normally the of Biscay to the Mediterranean; the widening case, the magnet is excited and the signal and deepening of the Seine, so as to make controlled thereby, so as to show that the Paris a seaport. line is clear. But when a train enters on the It is worthy of note that the chief engineersection, then a shorter circuit is made by the ing projects of the most recent times look wheels and axles, and the current returns to toward the extension and improvement of the battery by this course instead of passing water-communication. The construction of a through the signals. The magnet ceases now ship-canal through the American Isthmus, to attract, and the signal, by mechanical means, which has long been a cherished project of the is at once turned to indicate danger. It is ob- American people, may be said to be on the

core.

way to be realized. The commission appointed the deficient water-supply, was enough to conby the United States Government to consider demn the plan. The route between the gulf its feasibility, and select the best route, have of San Blas and the river Chepo or Bayanos presented a final report; and treaties are in has been supposed to be a specially desirable progress with other countries concerning it. one, because the tides from both oceans are The Dutch have achieved a great engineering nearer together at this point than elsewhere; success in the completion of the North Sea but the survey revealed insurmountable diffiCanal, which makes a seaport of the city of culties, even after an eight-wile tunnel should Amsterdam, floating the largest vessels, and have been cut. A survey from Caledonia Bay allowing direct steamboat communication with out discovered no pass at a less elevation than foreign pofts. The St. Gothard Tunnel is ap- 1,000 feet. Several other routes which were proaching completion ; but its undertakers surveyed showed difficulties still more formihave been greatly dismayed by the discovery dable. The Government has expended about of an enormous miscalculation in the estimates $60,000 in this investigation. of cost. Extensive and costly experiments The treaties with foreign powers are to be upon the proposed railway-tunnel through the made on the basis of the Clayton-Bulwer chalk-beds underlying the straits of Dover are Treaty of 1850, guaranteeing the neutrality of undertaken, and will amount to a commence the canal. The estimate of the cost returned ment of the work, if it shall be found feasible. by the commission is $65,722,157; but several In Italy we see the completion of an enterprise practical engineers, who have examined the which has been pursued for many years, by route, conjecture that obstacles will be enwhich a large tract of land, submerged for countered which will increase the cost to ages, has been recovered to agriculture. Other nearly $100,000,000. The work cannot be similar works are proposed for the reclamation completed in less than five years of hard labor; of the wide ranges of land which lie waste in but if it is sustained by the leading governthat country, covered with disease-generating ments, it is supposed that it will not be delayed marshes; while in Holland a plan is seriously or abandoned for want of funds. The distance entertained by the Government for the drain- to be excavated is 614 miles, and the total ing and fertilization of the bed of the Zuyder length of the canal, including 53 miles of slackZee, which would increase the territory of that water navigation, by way of the San Juan country about one-sixth, and afford a perma- River, and 56 miles across Lake Nicaragua, Dent revenue of millions of francs to the Gov- will be 180$ miles from ocean to ocean. For ernment. The long-expected Russian railway a number of years there has been a consideracross Central Asia has not yet been practically able and increasing transportation traffic by commenced, though the project is gaining the way of Lake Nicaragua and the San Juan favor. In our own country, the great works River. Whether a ship-canal across the Nicaof river and harbor improvement, which have raguan Isthmus would draw any of Europe's been carried on by the Government, are still trade with the East from the Suez Canal is under vigorous prosecution; the chief results doubtful; but the benefits it would afford to the of this year's labors have been the clearing American trade with the East and the Pacific away of Hallett's Reef, one of the most serious coast, and the improved communication it obstructions in the East River channel (see would render between the western side of the article HELL-GATE), and the deepening of the North and South American Continents, and chief outlet of the Mississippi (see below). the whole commercial world, would be much

The survey which has been conducted by the more than commensurate with its cost. commission of the American Government for An American engineer, Henry C. Spalding, five years past upon the isthmuses of Panama has broached a scheme for letting the waters and Nicaragua, with reference to a ship-canal, of the Black Sea into the Caspian through an has been completed within the year, and final artificial channel-way, thus greatly enlarging reports have been presented to the President. the area of the latter sea by the submersion of The route which was found most promising comparatively sterile tracks, but immensely and practicable was one across the Nicaraguan improving the fertility of the surrounding Isthmus, by way of Lake Nicaragua. Four other regions, and giving Russia maritime communiproposed routes have been carefully examined. cation with the commercial world, and a broad The one across the isthmus of Panama, for- sea-coast. His project is to cut a canal, 150 merly much thought of, was found to present metres wide, from a point in the basin of the the greatest difficulties. J. C. Trautwine, chief- Caspian Sea, which is 15 metres below the engineer of the Panama Railroad, lately ex- level of the Black Sea, in a westerly direction pressed an opinion that a canal over that route to such a point that it will have a depth of 10 would cost not less than $300,000,000! The metres; from there a narrower cutting is to be sarvey across the isthmus of Tehuantepec, carried on to the Black Sea. This narrower under Commodore Shufeldt and Engineer channel, he calculates, should have a depth of Fuertes, showed that the line proposed by three metres where it strikes the Black Sea, and those engineers by way of the river Coatzaco- a width of 50 metres; through this the water alcos would require the construction of as would flow with a velocity of 12 kilometres many as 140 locks, which, in connection with an hour, and, where it gives into the larger

channel, would have a fall of 10 metres, which by 46; and both are built upon no fewer than would give it a tremendous excavating power. 8,896 piles. The tremendous driving force of It would take about six years, he reckons, to the storms on the North Sea, and the shifting complete the excavations, and then about sands of the coast, gave rise to difficulties forty years for the waters of the two seas to which taxed all the resources of engineering approach near enough to a level to allow of skill. The plans of this great work were denavigating the canal. This time can be short- vised by the English engineers Sir John Hawkened to twenty-five years, he further proposes, shaw and Darnton Hutton. The canal receives by connecting the rivers Don and Volga vessels of any tonnage. At intervals it is enthrough another cutting.

larged into basins like the Suez Canal. The scheme of letting the waters of the At The plan for draining the Zuyder Zee was lantic into the desert of Sahara is gaining pronounced practicable and advisable by a favor. M. de Lesseps has expressed his opinion Government commission in 1873. During the that it can easily be realized, and advocates last couple of years it has been much discussed also the connection of the Congo and Zambesi in the Legislature, in the chambers of comrivers by a canal at the point where they ap merce, and by the press; and there seems every proach each other within eighteen miles, both likelihood that its practical execution will soon being navigable at that point. He considers be commenced. The most difficult part of the that the climate of Europe would be improved, work will be the construction of a great dike if anything, after the submersion of the desert, across the lake, from the town of Enkhuisen to and suggests that the fertile oases are all above the island of Urk; and then, with two angles, the ocean-level.

to Kampen, on the east side.

The length Reports on the improvement of the mouth of the dike is to be 40 kilometres, some 25 of the Mississippi show that the work is pro- miles, with a height of 8 metres, or 26 feet, gressing, and that satisfactory results have above high-water level, and a breadth of 50 already been attained. Grand Bayou has been metres, or 164 feet. Double sluices at Enkclosed, and the water which passed through it huisen, Urk, and Kampen, will communicate now makes its way through the pass, increas- with the sea. Alongside of the dike a 'canal ing the current and its scouring force greatly. will be made on the inside, and on the interior The width, depth, and straightness of the berm will be the tow-path and a railroad. channel are improved, and a recent statement The plan for draining the lake is to divide it of Captain Eads shows an average depth of into squares, which are to be successively 20 feet through nearly the whole length, the pumped out by immense steam-engines into exceptions being a spot near the upper end of canals of discharge, which will convey the the pass, and one within 1,000 feet of the water into the large permanent canals of marilower end of the jetties, about 75 feet together, time communication, leading into great reserwhere the depth is 19 feet in the shallowest voirs, from which the accumulated water will places. Captain Eads declares that the allu- flow out at low tide. Large commercial cavium carried out of the pass on the jetty sys- nals will be constructed between the harbors tem is not deposited so as to form a new ob- now situate upon the lake, of dimensions apstruction outside; but that, on the contrary, a proaching those of the new North Sea Canal large lump at the mouth of the South Pass has from Amsterdam. The largest of the canals been cut through by the increased strength of will be one from Enkhuisen to Amsterdam, the current, and is being gradually worn away. and one starting near Harderwyk, and going A series of dikes and wing-dams is in pro- along the southern shore to Huisen, then turncess of construction in the pass above the ing toward the Pampas, and joining the other jetties, which is intended to reduce the width line. Of the smaller order of canals, there of the channel gradually from 5,000 to 800 will be four principal lines, two parallel, runfeet, and accelerate the scouring out of the ning southwest and northeast across the bed pass.

of the lake, and two intersecting ones. For The Dutch opened the new North Sea Canal, the completion of the drainage, thousands of in the summer of 1876, amid festal rejoicings. small trenches and ditches must be cut over This canal, although but fourteen miles long, is the entire bottom in every direction. The of immense utility to the commerce of the construction of bridges and sluices will present country, and of the highest importance to the greater difficulties than the work of canalizaprosperity of Amsterdam ; and its construction tion. Three several kinds of sluices will have was attended with such difficulties as to place to be made—the great double sluices at Urk, it among the highest order of engineering Enkhuisen, and Kampen; and a score of others achievements. A great part of its course is of the same construction at all the crossings of over tracts which were submerged by an arm canals, the simple sluices for the outflow of of the Zuyder Zee, and had first to be pumped water, of which there will be three by the side dry to allow the bed of the canal to be dug of the three great double sluices, and the out. To prevent the sand-hills near the sea small sluices for irrigation, of which there from choking the canal, huge locks had to be will be great numbers distributed over the constructed. One of the locks is 315 feet long entire surface of the reclaimed lands. The and 59 wide, and another ship-lock is 239 feet mean depth of water to be drawn off is es

timated at 31 metres. If 9,400-horse power is 20,000,000 francs, to be devoted to harbor imapplied it is calculated that the lake will be provements. drained in about two years, at the rate of The tunnel under the English Channel, for 4,500 cubic metres per minute. The only effi- the commencement of which companies have cient power here applicable is supposed to be been formed in London and Paris, it is prothe steam-engine. After the steam-pumps posed to construct on the route proposed by have done their business, dredges will have to Sir Jolin Hawkshaw, from St. Margaret's Bay be employed to dig out the bottoms of the to a point near Sangatte on the French coast. can als, and clear away the mud, where large In this course it is expected that it will pass structures have to be built. For the founda- through chalk-beds the entire way, while in tion of many of the heavy structures it will be the route proposed by M. Thomé de Gamond necessary to sink piles and bundles of fascines, it is known that several different strata would as has been done in the making of the great be encountered. The distance across the ChanAmsterdam Canal. The entire work, it is es- nel in the proposed course is 22 miles, which, timated, can be completed in from twelve to with the long approaches necessary, would sixteen years.

The surface drained will be make 31 miles altogether. Shafts are to be 196,670 hectares, or about 795 square miles, of sunk on either shore to the depth of 450 feet which area about one-tenth will be taken up below high-water mark. At that depth driftby roads and canals. It is supposed that, with ways are to be driven, which will serve for the all allowances, there will be about 150,000 hec drainage of the works when in progress, and tares of fine, tillable land. The expense of the of the tunnel permanently. The tunnel will undertaking is estimated at 240,000,000 francs, commence 200 feet above the driftway, with a large estimate, exclusive of interest. If the an inclination of one foot in eighty down to Government should carry out the undertaking, the junction with the driftway, and then of as seems most likely, it is calculated that it one foot in 2,640 to the centre of the Channel, would bring in, after completion, an annual where it will meet that driven from the other revenue of 1,880,000 francs.

side. The dimensions of the tunnel will be Two enterprises for the reclamation of large those of an ordinary railroad-tunnel for two submerged tracts are successfully in progress tracks. A driftway, nine feet in diameter, it in Italy. The Ferrara Marshes, in Northern is proposed first to carry entirely through, Italy, are being drained by means of steam which can afterward be enlarged to the size of pumps, constructed by John and Henry the tunnel. A machine for tunneling in chalk Gwynne, of Hammersmith, England. The area has been invented by Dickenson Brunton, an to be reclaimed is 200 square miles. The en- English engineer, which has been successfully gines lift 2,000 tons of water per minute tried upon the bed of gray chalk through which through an average distance of seven feet three the tunnel is to be made. It works similarly inches. The maximum lift is twelve feet. The to an ordinary board-auger, cutting off the water is discharged into the river Volano, at chalk in slices, which fall upon an endless Cordigoro. Another large enterprise is the band, and are loaded upon wagons. The madrainage of Lake Fucino, which lies about 55 chine, it is found, can cut a driftway of seven miles east of Rome, and has an area of sixty-one feet diameter at the rate of something over a square miles, by means of a siphon 1,500 yards yard an hour. At that rate it would take two long, from canals which have been dredged out years to complete a driftway under the Chanat the bottom. The works have been going nel with a machine starting from each side. on many years, at the expense of the late The expense of completing such a driftway is Prince Torlonia, and the enterprise will soon estimated at £800,000, including interest upon become remunerative. This area was drained the outlay. Engineers and contractors of exby the Emperor Claudius, and the ancient perience have calculated that, after the driftworks were suffered to go to decay in the way should be completed, it would take four middle ages. The project was at first designed, years' time and £4,000,000 only to enlarge it to restore the Roman works, and a company to the dimensions of a raiload-tunnel, and tu was formed in 1855 for that purpose, and the construct the junctions with the railways work was intrusted to M. de Montricher, a on either side. It seems certain now that well-known French engineer. This was found the commencement of this work will soon be impracticable, and, the Prince Torlonia assum- made and its practicability tested. The coming the entire responsibility, the present works panies which have been formed for this purwere constructed. About 50,000,000 francs pose are to unite with the French and English have been expended upon them thus far. railways interested, and with the Rothschilds

There are suggestions of extensive improve- of London and Paris, in making up the sum of ments in the harbor of Genoa, and various £160,000, to be expended upon sinking a shaft plans have been proposed for the work. It has on either side to the depth of 450 feet, and drivlong been the dream of the Genoese to make ing a headway a short distance under the sea. their harbor the best in the Mediterranean, and The project of a tunnel under the North Iegain their ancient commerce and prestige on River from New York to Jersey City, for railthe seas. A nobleman of Genoese birth, it is way transportation, for which a company was said, bas presented the city with the sum of formed some time ago, gave rise to a long

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