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Boston elevated railway
CURRENT TOPICS.
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small or large ingots. On a large output the saving is estimated at from $2 to $3 per ton. The ingots obtained are free from blowholes, piping, and segregation. About 93 per cent. of the ingot may be utilized for commercial purposes. In mild steel the loss is about 8.8 per cent., and in 9rdinary steel about 7.9 per cent., the rest of the ingot representing~salable and serviceable billets. Zinc Alloys for Galvanizing. L. SANGER. (Zeit. Angew. Alloys containing 96 to 99.5 per cent. of zinc, 0.5 to 1.5 lead, o.I to 0. 5 iron, o.oi to o.I copper, 0. 5 to 2 tin, o.I to 0. 5 carbon, 0.05 to 0. 5 aluminum, are preferable to rolled zinc as anodes, because they cohere even when reduced almost to paper thickness. They are made in the shape of plates a n d rods, and other forms, from new and old metals.
Chemie, 2380. )
Propeller Erosion. (Engineering, xciii, 33.)--Manganese bronze temporarily solved the problem of preventing corrosion and erosion observed in the earlier type of steel propellers. The introduction of turbines caused the reappearance o f erosion often in a serious form; for example, a blade of a wing propeller of the Mauretania eroded to a depth of 2 .inches over an area of 3 or 4 square feet in a short time. O. Silberrad's researches have shown that, unlike corrosion, erosion is not selective as between copper and zinc, but that it depends on the structure of the alloy, removing the eutectic and leaving the mixed crystals. As a result of numerous tests an alloy, known as " Turbodium " has been produced. It has a tensile strength of 38 to 40 tons per square inch, a yield point of 18 to 19 tons, with an elongation of 15 per cent. on 2 inches. Under the laboratory standard erosion test, it showed an endurance of 14o hours, as against 24.7 hours for the ordinary high-tension bronze. This result has been confirmed by actual trials lasting from six months to three years on various turbinedriven vessels, none of whose propellers show any signs of erosion up to the present. Boston Elevated Railway. (Elect. R~y. Journ., xxxviii, I313.).--In this article there is given a complete account of the system of power generation and distribution of the Boston Elevated Railway. Owing to alterations and additions the whole system has become very complicated, and the original paper should be referred to, in order to arrive at a full comprehension of the subj e c t . The company has a total rated direct-current generating capacity of 5I,I83 kilowatts, but this will shortly b e raised to 64,7oo kilowatts by the purchase of power from the Boston Edison Company. This power will be converted from alternate to direct current for the use of the railway. The whole system is in process of being rearranged and simplified.
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small or large ingots. On a large output the saving is estimated at from $2 to $3 per ton. The ingots obtained are free from blowholes, piping, and segregation. About 93 per cent. of the ingot may be utilized for commercial purposes. In mild steel the loss is about 8.8 per cent., and in 9rdinary steel about 7.9 per cent., the rest of the ingot representing~salable and serviceable billets. Zinc Alloys for Galvanizing. L. SANGER. (Zeit. Angew. Alloys containing 96 to 99.5 per cent. of zinc, 0.5 to 1.5 lead, o.I to 0. 5 iron, o.oi to o.I copper, 0. 5 to 2 tin, o.I to 0. 5 carbon, 0.05 to 0. 5 aluminum, are preferable to rolled zinc as anodes, because they cohere even when reduced almost to paper thickness. They are made in the shape of plates a n d rods, and other forms, from new and old metals.
Chemie, 2380. )
Propeller Erosion. (Engineering, xciii, 33.)--Manganese bronze temporarily solved the problem of preventing corrosion and erosion observed in the earlier type of steel propellers. The introduction of turbines caused the reappearance o f erosion often in a serious form; for example, a blade of a wing propeller of the Mauretania eroded to a depth of 2 .inches over an area of 3 or 4 square feet in a short time. O. Silberrad's researches have shown that, unlike corrosion, erosion is not selective as between copper and zinc, but that it depends on the structure of the alloy, removing the eutectic and leaving the mixed crystals. As a result of numerous tests an alloy, known as " Turbodium " has been produced. It has a tensile strength of 38 to 40 tons per square inch, a yield point of 18 to 19 tons, with an elongation of 15 per cent. on 2 inches. Under the laboratory standard erosion test, it showed an endurance of 14o hours, as against 24.7 hours for the ordinary high-tension bronze. This result has been confirmed by actual trials lasting from six months to three years on various turbinedriven vessels, none of whose propellers show any signs of erosion up to the present. Boston Elevated Railway. (Elect. R~y. Journ., xxxviii, I313.).--In this article there is given a complete account of the system of power generation and distribution of the Boston Elevated Railway. Owing to alterations and additions the whole system has become very complicated, and the original paper should be referred to, in order to arrive at a full comprehension of the subj e c t . The company has a total rated direct-current generating capacity of 5I,I83 kilowatts, but this will shortly b e raised to 64,7oo kilowatts by the purchase of power from the Boston Edison Company. This power will be converted from alternate to direct current for the use of the railway. The whole system is in process of being rearranged and simplified.