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Action of light on coloring matters
714
CURRENT TOPICS.
[J. F. I.
A l u m i n u m as Flux. ROBERT GRIMSHAW. (Metal Industry, II, IO, 425.)--Iron founders have long known that aluminum is an excellent flux. It oxidizes very easily and removes oxygen from the cast iron and steel, according to the formula AI~ + O3 = A120,, evolving 39I,OOO calories, an amount of heat sufficient to raise the temperature of one kilogramme of iron 14oo ° C., or one pound 5544 ° F. This heat causes the sudden foaming of the mass. The energetic movement noticed in the pouring ladle brings the molecules in contact with air, which produces iron oxide ; but this oxidation can be avoided by covering the melted iron or steel rr~ss with sand or charcoal. If the melted metal does not attain a high temperature the effect of the addition of aluminum is almost nil. The amount of fluxing metal necessary depends on the quality of steel and the purpose of the casting., For steel with o. 5 per cent. carbon there should be added from 16o to 32o grains of aluminum per ton, while for a higher carbon steel only 15o to 250 grains are necessary.
Granacite. H. FISHER. (Zeit. Angew. Chem., xxv, 1327. ) Granacite, a form of granite found in Saxony, is especially suitable for towers, vessels, containers, etc., in the industrial manufacture o f acetic acid and white lead, phosphoric acid, bromine, and alkali manufacture, and in the paper industry for sulphite liquors. Action of L i g h t on Coloring Matters. W. HARRISON. (J. Soc. Dyers and Col., xxviii, 225.)--Experiments are quoted to show that: (I) Light from the mercury arc lamp does not act relatively the same as sunlight on all colors. (2) A mercury light of high intensity does not act relatively the same as one of low intensity. (3) Cellulose is decomposed by the action of light and air, with formation of reducing substances. (4) In a vacuum under the influence of light from a mercury lamp, cellulose acts as a reducing agent, but in a vacuum under the influence of sunlight, cellulose has little reducing power. This explains why direct dyestuffs do not fade in a vacuum under the influence of sunlight. (5) Most dyestuffs do not fade in the absence of fibre and air; direct dyestuffs do not fade in the absence of fibre; basic dyestuffs do not fade in absence of air. (6) Basic dyestuffs usually fade owing to oxidation. (7) Under the influence of mercury light, wool is not so powerful a reducing agent as cellulose. (8) Radium emanation has a powerful destroying action on cellulose, and on many direct and basic dyestuffs and on indigo; indanthrene and Para red, on the contrary, are only slightly affected. (9) Light from a mercury lamp browns and tenders both wool and silk. (IO) Many substances affect the rate of fading of dyestuffs; oils, for example, assist the fading of vat dyestuffs through oxidation, whilst dextrin appears to protect all colors. To explain these observations the author advances a theory based on Drude's explanation of color absorption. ,
CURRENT TOPICS.
[J. F. I.
A l u m i n u m as Flux. ROBERT GRIMSHAW. (Metal Industry, II, IO, 425.)--Iron founders have long known that aluminum is an excellent flux. It oxidizes very easily and removes oxygen from the cast iron and steel, according to the formula AI~ + O3 = A120,, evolving 39I,OOO calories, an amount of heat sufficient to raise the temperature of one kilogramme of iron 14oo ° C., or one pound 5544 ° F. This heat causes the sudden foaming of the mass. The energetic movement noticed in the pouring ladle brings the molecules in contact with air, which produces iron oxide ; but this oxidation can be avoided by covering the melted iron or steel rr~ss with sand or charcoal. If the melted metal does not attain a high temperature the effect of the addition of aluminum is almost nil. The amount of fluxing metal necessary depends on the quality of steel and the purpose of the casting., For steel with o. 5 per cent. carbon there should be added from 16o to 32o grains of aluminum per ton, while for a higher carbon steel only 15o to 250 grains are necessary.
Granacite. H. FISHER. (Zeit. Angew. Chem., xxv, 1327. ) Granacite, a form of granite found in Saxony, is especially suitable for towers, vessels, containers, etc., in the industrial manufacture o f acetic acid and white lead, phosphoric acid, bromine, and alkali manufacture, and in the paper industry for sulphite liquors. Action of L i g h t on Coloring Matters. W. HARRISON. (J. Soc. Dyers and Col., xxviii, 225.)--Experiments are quoted to show that: (I) Light from the mercury arc lamp does not act relatively the same as sunlight on all colors. (2) A mercury light of high intensity does not act relatively the same as one of low intensity. (3) Cellulose is decomposed by the action of light and air, with formation of reducing substances. (4) In a vacuum under the influence of light from a mercury lamp, cellulose acts as a reducing agent, but in a vacuum under the influence of sunlight, cellulose has little reducing power. This explains why direct dyestuffs do not fade in a vacuum under the influence of sunlight. (5) Most dyestuffs do not fade in the absence of fibre and air; direct dyestuffs do not fade in the absence of fibre; basic dyestuffs do not fade in absence of air. (6) Basic dyestuffs usually fade owing to oxidation. (7) Under the influence of mercury light, wool is not so powerful a reducing agent as cellulose. (8) Radium emanation has a powerful destroying action on cellulose, and on many direct and basic dyestuffs and on indigo; indanthrene and Para red, on the contrary, are only slightly affected. (9) Light from a mercury lamp browns and tenders both wool and silk. (IO) Many substances affect the rate of fading of dyestuffs; oils, for example, assist the fading of vat dyestuffs through oxidation, whilst dextrin appears to protect all colors. To explain these observations the author advances a theory based on Drude's explanation of color absorption. ,