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“ The canal, as designed, is about 100 miles long. Of this length, about half is sufficiently advanced for the sea-water to reach 50 miles, - that is, into the middle of the isthmus. It is finished to its full breadth, which is 100 yards, or the width of a considerable river, but not to the intended depth of 26 feet. The remaining 50 miles not yet penetrated by the sea-water are in various states of progress; parts are excavated, parts are under water, parts will have to be laid under water which is to be supplied from a great lake not yet filled, while a good many miles have to wait for blasting operations. To English ears it must sound promising that a good deal of clay has to be cut through; for nothing can be dealt with so successfully in this country as that material. The completion of the southern half of the canal would look like a very long work, but for the fact of the immense subsiding works being completed, and a vast mass of appliances being on the spot. The service canal, from the Nile to the mid-point of the salt canal, and branching thence to either extremity, is an immense work, not less than 150 miles long, and in full use for the supply of fresh water for navigation, and for otherwise assisting the work to be done. The port at the Mediterranean end is an immense work, already available. The sea-channel at the Suez end has difficulties, but only such as engineers are familiar with. Forty enormous and costly dredging-machines are at work on different parts of the canal,- chietly, we conclude, the northern half, - discharging mountains of mud, sand, and clay over the banks or into barges. The rate of expenditure is put at 200,000 pounds per month, or 2,500,000 pounds a year. Cur informant calculates that a driving wind, after blowing a month together, will send into the canal, when finished, 500 tons of sand a day, or 15,000 tons à month. This, however, is no more than a single dredging-machine would be able to keep down at a certain moderate cost in coal. The difficulty of keeping up the banks of the canal, exposed as they will be to the wash of the steamers, and to a surface often agitated by the wind, is a more serious matter, but one which does not enter into the present question. Upon the whole, it does seem a moral certainty that at least in two or 3 years — for one year seems out of the question — this great undertaking, worthy of a heroic age, will be brought to what we may fairly call an actual completion. In the course of the year 1871 we may probably see the sea-water of one ocean flowing into the other.

SUEZ CANAL.

The following figures show the condition of the work on the canal on 1st January, 1869, also the progress made during the past year. The two exhibits, taken together, may give us the data for calculating the time when the entire work will be completed. The estimates of quantities are given in cubic metres, to which 37 per cent. should be added to show the results in cubic yards. The aggregate amount of earth to be inoved, to dig the canal according to the plans adopted, was 74,112,130 cubic metres; of this there remained on 1st January, 1868, 40,000,000 cubic metres yet to be done. The time now named by Mons. Laralley for the entire completion of the work is 1st October next, and there seems to be no reason to doubt his ability to make good this prediction. The success of the dredging-machines has been even beyond the anticipations of their strongest advocates. One machine is credited with 108,000 cubic metres of excavation, in a single month; another with 88,889; another with 78,056 cubic metres within a like period. They have double gangs of men, and work night and day. Six dredges in November, in the Port Said division of the canal, raised 313,628 cubic metres; three other machines, at Ras-el-Ech, raised 214,042 cubic metres. The last new dredge of the contractors was put at work in December; and now their entire force, 60 machines, is being driven to its utmost capacity, in order that the canal in its full dimensions may be opened to the commerce of the world with the least possible delay. The piers or jetties at Port Said are entirely finished. The western pier was completed on the 8th September, and the making of the concrete blocks was stopped the same day. On 15th December, there remained but 316 blocks to be sunk to finish the eastern pier; and these could easily be handled in 10 days. The harbor and basins at Port Said have been dredged to a depth throughout of 23 feet; and now the French, Russian, Austrian and Egyptian steamers touch there regularly. No difficulty is experienced in running into this harbor at any time of day, or in any weather; whereas at Alexandria no vessel drawing 15 feet ever attempts to enter except by day; and, in heavy weather, steamers have been obliged to wait outside the bar for two and three days, on account of the narrow, shallow entrance to the harbor. During the first 6 months of last year 813 vessels entered at Port Said, landing 3,282 passengers, and 105,832, tons of merchandise.' The Viceroy of Egypt has ordered the line of railway between Cairo and Suez to be abandoned ; and a new line of railroad has been constructed from Alexandria and Cairo to Sucz, by way of Lagazig and Ismailia. This new route was opened in November last; and henceforth Ismailia will be the stopping-place on the Isthmus for passengers between Europe and India, while waiting for their steamers either in the Red Sea or the Mediterranean.

SMELTING, CARBURIZING, AND PURIFYING IRON. Mr. Isham Baggs, of High Holborn, has patented some processes by means of which the smelting, carburization, and purification of iron are greatly facilitated. In charging the furnace, the coal or coke usually thought necessary for smelting is in a great measure dispensed with, and in its place Mr. Baggs burns in the smelting-furnace coal gas, hydrogen, carbonic oxide, or other combustible gas or gases, and also the vapor of petroleum, naphtha, and other hydrocarbons under pressure, and in combination with a blast of hot or cold air. In the case of the infiammable hydrocarbon vapors, the same may be forced into the furnace under the pressure of their own atmospheres, or by means of mechanical appliances. The gases and vapors which are employed for the purposes of this invention may be previously mixed with the air furnished by the blast, or may be caused to meet the air in the furnace or at the tuyeres. The proportions of the mix. ture, when a combination of gas or vapor and air is employed, are subject to constant regulation by valves. One very convenient mode of obtaining combustible gases for the purposes of this invention is to generate coal gas in the usual way, and then carbonic oxide, and to blow air or carbonic oxide gas under pressure throngh the retort containing the residual coke. For the purpose of carburizing the iron, whether in or out of the furnace, as may be desirable, coal gas or other carbides, or other materials containing carbon, are blown through the furnace, or brought into contact with the molten metal by blowing them through it. Carbon in any suitable form or combination may also be directly introduced into the furnace for the purpose of carburization, and although generally for smelting purposes it is desirable to exclude all solid mineral fuel from the furnace as part of the charge, yet where a suspension of operations is necessary, such a charge of coal, coke, or other fuel may be introduced into the furnace as will prevent the materials, on renewal of work, from falling through the crucible or any iron remaining therein or below it from being permanently solidified. When purification is required, hydrofluoric acid is blown through the molten metal in its way from the furnaces, the gases being mixed with common air, or with some gaseous diluent.

· Mechanics' Magazine, Sept., 1869.

BESSEMER ON THE HEATON STEEL PROCESS. Mr. Henry Bessemer, the inventor of the Pneumatic process, addresses a letter to the “ London Times,” under date of Dec. 1, in reply to an article in that paper, to the effect that by the Bessemer process no good malleable iron or steel can be produced from inferior pig, while, by the Heaton process, steel is produced from very inferior pig iron, and steel of the first class. The exception taken by Mr. Bessener in his letter is, that the steel produced by Mr. Heaton is not homogeneous or cast steel, but has the general nature of puddled steel; that is, is laminated and fibrous in form, besides appearing in the shape of porous steel sponge, similar to the iron sponge produced from a Swedish fur

Heaton's result, Mr. Bessemer says, can only be converted into cast steel by the old Sheffield crucible process, at a cost of from 5 to 6 pounds sterling per ton. The nitrate of soda (270 pounds) necessary to reduce a ton of pig by the Heaton process, costs 6 pounds sterling on the average; so that while the inferior pig used by the Heaton costs 5 pounds less per ton than that used by the Bessemer process, the cost of the nitrate overbalances this gain on the ton by one pound sterling. The result is, that laminated steel, which must be remelted at a cost of 5 or 6 pounds to the ton to produce cast steel, costs a pound more to the ton by the Heaton process than good homogeneous steel from the best Cumberland pig costs by that of Bessemer.

nace.

Mr. Bessemer concludes that there can be no competition between his process and Heaton's.

BESSEMER'S HIGH-PRESSURE FURNACE. Theoretically the total quantity of heat required to raise from an ordinary temperature and fuse a ton of steel does not exceed by more than 30 per cent. that requisite to melt the same weight of cast iron; but practically, the amount of fuel is 30 times as great in the former as in the latter operation. This waste is due to the fact that the temperature required for the fusion of the metal comes very near the maximum temperature which can be obtained in the furnace, and the heat is communicated to the metal much more slowly than if a greater difference of temperature were available. The production of a very intense heat on a large scale is, practically, very difficult, as it is necessary to guard against radiation and too great access of air, and to secure the complete conversion of carbon into carbonic acid ; the systems of Mr. Siemens-and Mr. Schinz, using as fuel carbonic oxide wholly or in part, have remedied the evils in a high degree. Mr. Bessemer's system may be employed as readily for the combustion of heated air and gases as for solid fuel with a cold blast. Mr. Bessemer, while meditating the construction of a large lens, 20 feet in diameter, to be mounted equatorially, to collect the rays of the sun from an immense surface for hours together, was led to inquire why the solar heat was so intense; and the solution was that the great intensity of the solar heat was due to the fact that the combustion of the solar gases took place under great pressure, the force of gravity being at the sun's surface 27.6 times as great as it is at the surface of the earth. He therefore constructed a small cupola furnace, in which the products of combustion could not freely escape, but were maintained under a pressure of 15 to 18 pounds per square inch above the atmosphere. With this moderate pressure, steel and wrought iron may be melted more readily than cast iron in an ordinary cupola; 3 cwt. of wroughtiron scrap, introduced cold into a small furnace, was run off completely fluid in 15 minutes. This process, which marks an epoch in the application of heat for metallurgical purposes, is fully described and illustrated in the London Engineering,” for Sept. 17, 1869.

THE OXYHYDROGEN LIGHT.

The Oxyhydrogen Light scheme has now taken a definite shape in Paris. A company has been formed, the capital necessary has heen raised, and application has been made for permission to lay down pipes to carry oxygen and hydrogen over about a fourth of the city. It is not very likely that the permission will be granted, and the promoters will have to confine themselves to supplying individuals with compressed gases, as was originally proposed.

The prospectus of the company enlarges upon the cheapness and purity of the light, the complete combustion, and the absence of all deleterious matters in the products of the combination; but is quite silent as to the danger of introducing into a house two gases not possessing any smell, and which, consequently, may escape without observation, and the mixture of which forms an explosive compound of far greater power than any mixture of coal gas and air. "To any danger of this kind, continental engineers appear to shut their eyes. We saw, a short time ago, a patent taken out in Belgium for making a mixture of coal gas and air, storing it in gas-holders, and distributing it over the city of Brussels for heating purposes. The engineering details given showed a complete knowledge of the subject of the manufacture and distribution of gas, but there seemed to be no recognition of the risk, imminent enough, of blowing up the whole concern. A consideration of this kind, some years ago, stood in the way of a scheme of the kind projected for Birmingham, and will, no doubt, prevent the Oxyhydrogen Light Company from getting permission to lay down their pipes over Paris. – Journał Franklin Institute.

NORWEGIAN BOXES OF FELT FOR COOKING.

Prof. Joy, of Columbia College, describes the contrivance and its use in the following terms:

Another adaptation of well-known scientific principles is to be found in the use of Norwegian felted boxes for cooking food. There are few devices more simple or more valuable than this. From an economical point of view, such contrivances pay for themselves a thousand-fold, and in a sanitary direction there is no estimating their value to the poor laborers, as well as to the rich consumers of half-cooked food.

“It is curious how little these boxes are known; but, thanks to the Paris Exhibition, this ignorance bids fair to be of short duration. The whole thing is so absurdly simple that that is probably one reason why so little attention has been paid to the subject. We will attempt a description of the apparatus. Take a box a foot square, line it with successive layers of felt, leaving a round space in the centre large enough to hold the kettle customarily used for cooking food. Have a thick cap to cover up the kettle after it is introduced, so that it is in the middle of the box surrounded by a thick layer of non-conducting material. When it is required to boil meat, it is only necessary to heat the kettle for a few minutes up to the requisite temperature, and then to put it into the snug place prepared for it. Here the cooking will go on by itself as long as may be desirable, up to certain limits; and the meat will remain warm for 5 or 6 hours. By having a series of these boxes, the dinner can be prepared at no expense, save the original cost of starting the fire. A little experience will enable the cook to determine the length of time to leave the kettles in the boxes. It is easy to be inferred that the same arrangement will serve to keep ice-cream from melting, or substances from growing warm which have been previously cooled

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