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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
means of thermocouples. The charcoal was surrounded by an air space about 3 inches wide, and the oven could be closed airtight or a current of air of any desired velocity passed through it. Experiments with flake charcoal showed t h a t with air currents ranging from 5-62 cu. f t . per minute for I cu. f t . of charcoal, spontaneous combustion occurred at temperatures of from 96-11o0 C., while a t lower temperatures no signs of spontaneous heating could be observed. Additional experiments showed that in a current of air containing 5 per cent. sulphur dioxide, spontaneous combustion of the charcoal took place after some hours; therefore, there is risk of danger in using sulphur dioxide for disinfecting rooms, etc., where charcoal is present in the walls. It is reported t h a t decayed wood appears to be much less inflammable than charcoal.
ARTIFICIAL RUBBER FROM SEAWEED. A product, now being marketed under the name “Seagumite,” said to be non-inflammable, damp-proof, and unaffected by heat or cold, and to be expected to provide a substitute for rubber and leather, is the subject of a patent recently issued t o J. S. Campbell, of London (English Patent 5395, 1911). His invention relates to improvements in the production of a substance having the characteristics of rubber and capable of vulcanization. It had previously been proposed t o treat marine plants, lixiviated by acidulated water, with alkalies such as ammonia; and it is said that the material thus produced has, after impregnation with siccative oil or dissolved india-rubber, been found suitable for use in the whalebone industry. The Campbell process consists in boiling washed and crushed seaweed in steam-jacketed pans with ammonia for about 45 hours, I gallon of ammonia (specific gravity, 0.88) being used for 5 cwts. of seaweed; drying in an agitating apparatus, t o which heat is applied, and during agitation adding I gallon of a mineral or vegetable oil, as rosin oil; adding next a vulcanizing substance, such as sulphur, and subsequently mixing the whole mass with 25 per cent. by weight of a glutinous or resilient binder, as pontianac gum, jelutong, gutta-percha, or reclaimed rubber waste. The whole is then heated for I hour and finally dried in a vacuum pan or press. Prior to removing and drying, a preservative, as wood or bark extract, may be added to the amount of 0.85 per cent. by weight of the seaweed used. The Campbell process seems to be primarily dependent upon the formation of ammonium alginate. Algin in its soluble forms is recognized as having probable value as a n agglutinant, and a substance resembling gutta-percha may be prepared from the alkaline alginates and shellac.‘
J u l y , 1912
inferior in cutting value. The sharp cutting implements were therefore the result of Nature’s handiwork, and it is indeed very questionable whether these people possessed the sec e t of tempering.
THE PURIFICATION OF AIR BY OZONE. Nature, 89, 304, states that the system of ozone production and distributing plant installed for air purification and ventilation on the Central London Railway is a plenum one, and consists of Sirocco fans placed a t each of the underground stations, except that at Shepherd’s Bush. The total air supplied to the tubes is about 80,000,000 cu. ft. per day. Each fan draws its air through a filter screen, and works in conjunction with a n ozone-generating plant. The latter consists of mica sheets with metallic gauze on each side, stacked side by side, and energized by alternating current at about 5,000 volts, in such connection t h a t a silent discharge passes between the various plates, so that air passing between them is ozonized. The ozone generator is supplied with a small transformer, which in turn is supplied with 380 volts alternating current from a small rotary converter. The converter is connected on its directcurrent side t o the 5go-volt lighting circuit of the railway. THE USE OF COKE-OVEN GAS. Cooper (/. Gas 1-tg., 118, 107) states that in Germany the towns of Waldenburg, Altwasser, Salzbrunn, Essen, Dortmund, and Mhlheim have been supplied for some time with gas from the neighboring coke-oven plants. The entire supply of gas for Mulheim-on-the-Ruhr and for Barmen is obtained from two coke-ovcn plants. The installation consists of 50 Koppers’ horizontal regenerator ovens, each of which is capable of taking a charge of 8-10 tons of coal; the period of carbonization is 2 4 hours and only the richer portion of the gas (that evolved from the second to the twelfth hour, representing 50 per cent. of the yield) is used for distribution. During this time one oven will produce 70,600 cu. f t . of gas possessing a calorific value well over 600 B. t. u. per cu. ft. and costing $0.17per 1,000cu. ft The gas is purified from hydrogen sulphide by the town authorities and distributed.
THE PRESERVATION OF WOOD WITH “BELLIT.” I n order to increase the preservative effect of sodium fluoride on wood, it is now being mixed with nitro-phenols. According to Nowotny (Oesterr. Chem. Ztg., 15, 100;cf. Idem, Ij, SI),one of these mixtures, “Bellit,” consists of 90 parts of 90-95 per cent. sodium fluoride and IO parts of dinitrophenolaniline. The latter compound is used because it does not, like free dinitrophenol, act upon the iron vessels in which the timber is impregnated; it is also active as an antiseptic. The selective “TEMPERED COPPER” TOOLS. According to The Engzneeiing and Mimtzg , J o u r m l , gj, No. phenomena observed when treating timber with mixtures of zinc fluoride and hydrochloric acid are reproduced in the 20, 986,the copper-cutting instruments of the Tarascans, found “Bellit” treatment. in the Balsas River ruins in Guerrero, are so hard that they would turn the edge of a modern knife, and it has been claimed CHROME-NICKEL BRONZE. t h a t these people, along with the Aztecs and Toltecs, possessed Chrome-nickel bronze is now being manufactured by a Philathe secret of tempering copper. On the other hand, copper knives and axes, found a t Atcopotzalco, are so soft t h a t they delphia company, the product being known as “Chromax can be cut with a n ordinary pocket knife. Analysis showed Bronze.” The proportions of metal in the alloy are said to be t h a t in all three localities the copper implements were of the as follows: Copper, 66.66 per cent.; zinc, 12.13 per cent.; same composition as the copper ores found therein. The nickel, I 5 . I j per cent. : chromium, 3 03 per cent. : and aluminum, blades from Guerrero, which are hard and apparently tempered, 3.03 per cent. The tensile strength of the alloy is said to be we-e made from the natural ore carrying nickel and cobalt, 79,000 lbs. per sq. in.; the color is white, and i t takes a fine, thus rendering the smelted alloy steel-like in hardness. Thus, silvery polish: the fracture is fine and dense, particularly after the natural product gave a n alloy of great hardness when heated being remelted; and the alloy, owing to its high melting point, and sharpened, while the other ores of practically pure copper, has a denser structure and greater compressive strength than when smelted, resulted in implements whi h “ere soft and manganese bronze. It can be rolled into sheets and wire.
