60 grains of carmine with the solution. Mordant the fabric with a mixed solution of acetate of alumina and tin salt, and write upon it, when it is perfectly dry, with the ink.—18 C, March 5, 1876, 160.

INCREASING THE ADHESIVENESS OF COURT-PLASTER.

Court-plaster applied, as is usually done, by moistening it with the tongue, does not adhere well, on drying, to the unabraded skin adjoining the wound. By moistening the back of the plaster after it has been applied with glycerine, or, still better, by moistening the adhesive side of it when about to apply it with water to which one tenth of glycerine has been added, instead of with the tongue, the plaster will be kept adhesive and soft.-4 C, VIII., 1875, 72.

WATER-PROOFING UMBRELLAS, ETC.

Fischer, of Erfurt, suggests that, by the following treat ment, umbrellas of alpaca, etc., can be rendered water-proof without impairing their color, flexibility, or durability, so that they will not become heavy with rain, and can be put away immediately after use without necessity for drying: Dissolve one part of shaved paraffin (a piece of paraffin candle will answer) in 10 to 15 parts of benzol by shaking it in a bottle. Pour the solution over the whole of the expanded umbrella rapidly in spiral lines, beginning at the top. Great care should be taken not to conduct the operation near a lamp or stove.-8 C, August 26, 1875, 312.

IMITATION OF STRAW, LEATHER, AND WICKER-WORK, Imitations of straw, leather, wood, and wicker-work articles are produced by Löwenberg by the following process: A mould of the article to be imitated is made by pouring around it a mass consisting mainly of glycerine and glue. Into this, when firm, a liquid consisting chiefly of glue, glycerine, oil or soap, and some pigment, is poured, and before the whole of it sets the larger part is poured out again, leaving but a comparatively thin film, which constitutes the imitation when firm. Adhesion to the mould is prevented by treating it with chromic acid or acetate of iron.-6 C, September 9, 1876, 358.

L. MECHANICS AND ENGINEERING.

PRESERVATION OF WOOD.

According to Lostal, wood is rendered quite hard, and capable of resisting decay for a long time, by covering it in a large cistern with unslaked lime, and adding water from time to time until the lime is slaked, and allowing it to remain, according to the size of the pieces, until it is sufficiently penetrated by the lime-water; for that to be used in mining operations a week will suffice.-18 C, February 9, 1876, 95.

CARBOLIC ACID AND THE PRESERVATION Of wood.

The impression that a solution of carbolic acid has a preservative action on wood, founded on the assumption that tar preserves wood by reason of the carbolic acid and creosote it contains, is asserted by M. Boucherie to be entirely erroneous. Samples of different kinds of wood impregnated with one-half per cent., one per cent., and two per cent. solutions of carbolic acid, and then buried in a soil rich in humus, were found to be as completely decomposed after six years as samples that had not been so treated, while others impregnated with one and a half per cent. solution of sulphate of copper were unchanged.-28 C, IV., 66.

NEW PROCESS FOR THE PRESERVATION OF WOOD.

A new process for preserving wood from fire and decay has been invented by Messrs. Weatherby and Moore. It consists first in kiln-drying the wood, which deprives it of all moisture, and much of its volatile turpentine and other inflammable matters. It is then put into suitable cylinders, in which lime and water, with sulphurous acid gas, are forced into the pores of the wood under considerable pressure. The wood is removed, dried, and is then ready for use. The chemistry of the process consists in the formation of a soluble sulphate of lime by means of the sulphurous acid and the lime; this crystallizes as a bisulphite, which oxidizes and is converted into the sulphate of lime or gypsum. As this is an exceedingly insoluble salt, it is not easily removed from the pores

of the wood, and not only by its presence protects it as a nonconductor of heat, but deoxidizes all matters which are likely to prove objectionable as ferments.-1 A, XXXI., 75.

NEW PROCESS FOR INJECTING TIMBER.

In this process, the invention of Mr. G. B. Smith, any antiseptic compound that may be preferred is applied in solution directly to the end of the green log, and by the application of hydraulic pressure is forced to enter by the natural sap channels of the wood, by which operation the sap is forced out at the other end. The necessary pressure is maintained by the use of an ordinary hydraulic pump until all the sap is expelled, and the preserving solution appears in full strength at the farther end, when the thorough saturation of the log is most effectually assured. The mechanical appliances are simple, consisting merely of a cast-iron cap, fitted tightly against a metal ring driven into one end of the log, by means of a chain, or rod, and clamp passing over the other end, and communicating directly with the pump.

IRON AND STEEL FOR BOILERS, BRIDGES, ETC.

At a meeting of the Franklin Institute, committees were appointed to investigate the subject of the strength of iron and steel, with directions to make such experimental trials as may be necessary to include materials such as are at present found in the market, and employed for the construction of boilers, bridges, and other structures of iron and steel. In pursuance of this resolution, the sum of $1000 was appropriated for the purpose of defraying the cost of the purchase and preparation of samples of iron and steel for the testingmachine.-7 D, September, 1875.

CAST STEEL FOR LOCOMOTIVE BOILERS.

According to the Society of German Railroad Engineers, the use of cast steel for locomotive boilers has not been so satisfactory as was expected.-18 A, XXI., 89.

BESSEMER PROCESS WITH HOT BLAST.

Heyrowsky states that during the summer of 1874, at the Bessemer works in Zeltweg, fifty to sixty charges were made simply with a hot blast of about 1200° with cast iron, the an

alysis of which gave 0.8 per cent. silicon, 2.23 per cent. carbon, and 2.2 per cent. manganese. After the fusion it contained 0.7 per cent. silicon, 2.3 per cent. carbon, and 1.3 per cent, manganese. The charges were very hot, and the expectation, founded on theoretical considerations, that a slightly carburetted iron could be Bessemerized with hot blast, was confirmed. A larger than usual quantity of ends of rails could also be thrown in, amounting to eighteen per cent. instead of twelve per cent., as with cold blast. Among the practical difficulties that prevented its continuous use was the decided effect upon the lining, which often became useless after two charges, instead of withstanding an average of fifteen or sixteen; and, besides, all portions in contact with the hot blast were so intensely heated that they rendered manipulation difficult, and it would require long practice to accustom the workmen to the heat. For this reason the use of the hot blast was abandoned for the present, although the results were considered favorable.-13 C, July 1, 1875, 851.

EXTENDED SERVICE OF A FURNACE.

The Emma Furnace managers have communicated to the American Manufacturer the extraordinary announcement that the furnace stood banked up from December 4, 1874, to July 9, 1875, without blast or draught, during a most severe winter. This is equivalent to seven months and five days, or 217 days, and during all of this time it held its fire intact without chilling or cracking. On December 4th the iron was run out, and the furnace filled wholly with Connellsville coke, every precaution being taken to have the fire remain until advisable to resume operations. It stood idle until January 9, 1875, and during this entire time not a thing was done to it, or a pound of fuel added. When opened at above date some two thirds of its coke was alive, and the furnace, after clearing away ashes, etc., was ready to resume operations. This record of the "Emma" has to our knowledge never been equaled.

REVOLVING FURNACE BARS.

Foreign technological journals find a very considerable improvement in furnace grates in an invention of M. Eloy Schmitz, who replaces the straight fire-bars ordinarily used

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singly or in pairs, by hollow cylindrical bars pierced with holes, and so arranged as to revolve readily. The new firebars rest on supports which are themselves cylindrical and hollow; they are supported lengthwise by a plate fixed beneath the door of the fire-box, and fitting into a neck made at the near end of the bar. With this construction, it is affirmed, the duties of the stoker are rendered much less important and troublesome, and a very material economy of fuel is ef fected. The following advantageous features are claimed for it: The layer of coal resting on the grate may be doubled in thickness, thus obviating the necessity of frequent charg ing and the entry of cold air into the fire-box. The interior of these hollow bars being always visible to the stoker, he is able to observe any choking of the air passages as soon as it takes place. It is only necessary for him then to give the bars a fractional turn with the winch, and a clear surface, free from slag and scale, is presented to the fuel. This is accomplished without opening the doors and admitting an excess of cold air. The rotation of the bars has the additional beneficial effect of clearing the obstructed part and throwing down into the ash-pit the ash and other non-combustible impurities, the retention of which retards combustion. The economy of fuel which is claimed for the new construction is of even more importance than the economy of labor.

AMERICAN MINING METHODS.

One of our Comstock mining engineers, lately returned from a tour of inspection through the mining districts of Germany, communicates to a California daily his conviction that there is no engineering in Germany to compare with that on the Comstock lode, and no mines in which the mechanical appliances are so ingenious and effective. He supports this assertion by a graphic description of the crude and primitive methods in vogue abroad. He remarks that in the deep mines of Bohemia the hoisting apparatus consisted merely of open tubs, and the operating machinery was so poorly constructed that he dared not venture to descend. In most of the German mines, he found that the men were compelled to walk up or down to the scene of their labors, either by going down an incline, or by using long parallel stilts, which move up and down alternately about six feet at a time. The mode