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Hypochlorite treatment of water supplies
SIMPLICITY
IN MEASURES.
149
any steps in the wrong direction, away from this path to the ideal. approximatioa to this ideal system is already in extended use among physicists under the name o’f c.g.s. sNystem, and there appears to be no reason why engineers, who apply physical laws to practical proSblcms of construction, should not also enjoy the advantages of similar simplicity in their practical work.
A close
Iron Ore Resources of the World. L. DE LAUNAY. (1~ron Age, lxxxvi, 12.)-An article worthy of close consideration by iron producers and users. M. de Launay refers also’ to probable new iro’n ore development, after the reserves now in sight are largely exhausted. Northern Sweden contains large quantities of rich iron ores of more than 60 per cent. Recently iron ores have been discovered in the Lake Superior region, known to contain 2,000,000,000 tons of metallic iron, with a possible 36,000,000,000 tons. When Canada is explored, no doubt important discoveries will be made there. Newfoundland appears to have almost 2,000,000,000 tons of iron ore containing 65 per cent.; and similar ores are abundant in the Adirondacks. In the Southern Hemisphere, Minas Geraes is to be taken into account. For lower grades of ore, France may take the most prominent position with its supplies in Lorraine, Normandy and Algeria; followed by Germany with its ores found in German Lorraine. The Mechanigraph. (Irorz Age, lxxxvi, x3.)-This machine renders an opaque pencil or pen drawing transparent and printable practically instantaneously, at a cost of approximately one-third of a cent. per square yard. The drawing to be treated is passed through the first pair of romllswhich carry it through the bath containing the transparantor liquid, and from there along the moving tapes to the drying rollers, which are warmed by a current regulated by the rheostat beneath. The pressure on the drying rolls is maintained by adjustable, spherical iron weights. Hypochlorite Treatment of Water Supplies. GEO. A. JOHNSON. (Eng. Record, Ixii, 12.)- In view of the belief gradually gaining ground that mere filtration through sand is by no means a certain arrcstcr of bacteria, and thus is unreliable as a water purifier, the above paper on the use o’f hypochlorites as a germicide is of interest. Mr. Johnson summarizes the advantages of the process thus : I. Substantially complete destruction of objectionable bacteria particularly those of intestinal origin. 2. Reliability and ease of application’ of the ch‘emic&l and small variation of required do’se.
I.50
CURRENT ‘Tories.
either in the chemical or in 3. Absence of poisonous features, its resultant decomposition products. 4. Nominal cost both of chemical and its application. 5. Speed of reaction, requiring no substantial basins other than storage facilities. 6. Saving in cost of coagulation of waters requiring clarification or filtration. 7. Permitting a very high rate o f filtration, with high bacterial efficiency. 8. Redtices clogging of filter beds, and lengthens runs between cleanings, by destroying various forms of alga. Its limitations are: Inability to remove or destroy (1 j all of the spore forming bacteria (these are not considered pathogenic to man), (2) bacteria imbedded in suspended water, (3) inability to remove turbidity or (4) appreciable amounts of color, or (5) organic matter, or (6) swampy tastes or odors, or (7) creosote tastes or odors, and (8) inability to soften water, and (9) difficulty of application to waters containing reducing agents. Blistering of Sterling Silver during Annealing. AXON. (Brass World, vi, 349.)-It is possible to produce blisters on perfect sterling silver by overheating it during annealing in an oxidizing atmosphere. It is generally assumed that the blisters are the fault of the metal itself, and are caused by careless or imperfect melting; this is asserted to be radically wrong. Experiments show that sterling silver cannot be blistered when a reducing flame is used for annealing, but an oxidizing flame produces numerous blisters. The theory is advanced that silver absorbs oxygen energetically when the temperature approaches the melting point. Slow Rusting Iron Produced in the Open-hearth Furnace. ANON. (,%a,~. News, lxiii, 6.)-“ American ingot iron” has recently been placed on the market by the American Rolling Mill Co., which exhihits a high resistance to corrosion and is therefore valuable as a structural material. Although produced by the basic open-hearth process it is closely similar to’ wrought iron. It differs from steel in that its contents of carbon, manganese, and silicon are only fractions of the amounts in ordinary soft steel. In appearance, strength, and ductility this is practically identical with wrought iron. The usual ferromanganese recarburizer is omitted and ferrosilicon, or an equivalent, is used to purify the bmath of its oxides. Aluminum is added in the ladle to carry off the gases dissolved in the fluid metal. Relative corrosion resistance. tests with sulphuric acid show that ingot iron has 40 to 60 times the resistance of steel, and 20 to 40 times the resistance of wrought iron.
IN MEASURES.
149
any steps in the wrong direction, away from this path to the ideal. approximatioa to this ideal system is already in extended use among physicists under the name o’f c.g.s. sNystem, and there appears to be no reason why engineers, who apply physical laws to practical proSblcms of construction, should not also enjoy the advantages of similar simplicity in their practical work.
A close
Iron Ore Resources of the World. L. DE LAUNAY. (1~ron Age, lxxxvi, 12.)-An article worthy of close consideration by iron producers and users. M. de Launay refers also’ to probable new iro’n ore development, after the reserves now in sight are largely exhausted. Northern Sweden contains large quantities of rich iron ores of more than 60 per cent. Recently iron ores have been discovered in the Lake Superior region, known to contain 2,000,000,000 tons of metallic iron, with a possible 36,000,000,000 tons. When Canada is explored, no doubt important discoveries will be made there. Newfoundland appears to have almost 2,000,000,000 tons of iron ore containing 65 per cent.; and similar ores are abundant in the Adirondacks. In the Southern Hemisphere, Minas Geraes is to be taken into account. For lower grades of ore, France may take the most prominent position with its supplies in Lorraine, Normandy and Algeria; followed by Germany with its ores found in German Lorraine. The Mechanigraph. (Irorz Age, lxxxvi, x3.)-This machine renders an opaque pencil or pen drawing transparent and printable practically instantaneously, at a cost of approximately one-third of a cent. per square yard. The drawing to be treated is passed through the first pair of romllswhich carry it through the bath containing the transparantor liquid, and from there along the moving tapes to the drying rollers, which are warmed by a current regulated by the rheostat beneath. The pressure on the drying rolls is maintained by adjustable, spherical iron weights. Hypochlorite Treatment of Water Supplies. GEO. A. JOHNSON. (Eng. Record, Ixii, 12.)- In view of the belief gradually gaining ground that mere filtration through sand is by no means a certain arrcstcr of bacteria, and thus is unreliable as a water purifier, the above paper on the use o’f hypochlorites as a germicide is of interest. Mr. Johnson summarizes the advantages of the process thus : I. Substantially complete destruction of objectionable bacteria particularly those of intestinal origin. 2. Reliability and ease of application’ of the ch‘emic&l and small variation of required do’se.
I.50
CURRENT ‘Tories.
either in the chemical or in 3. Absence of poisonous features, its resultant decomposition products. 4. Nominal cost both of chemical and its application. 5. Speed of reaction, requiring no substantial basins other than storage facilities. 6. Saving in cost of coagulation of waters requiring clarification or filtration. 7. Permitting a very high rate o f filtration, with high bacterial efficiency. 8. Redtices clogging of filter beds, and lengthens runs between cleanings, by destroying various forms of alga. Its limitations are: Inability to remove or destroy (1 j all of the spore forming bacteria (these are not considered pathogenic to man), (2) bacteria imbedded in suspended water, (3) inability to remove turbidity or (4) appreciable amounts of color, or (5) organic matter, or (6) swampy tastes or odors, or (7) creosote tastes or odors, and (8) inability to soften water, and (9) difficulty of application to waters containing reducing agents. Blistering of Sterling Silver during Annealing. AXON. (Brass World, vi, 349.)-It is possible to produce blisters on perfect sterling silver by overheating it during annealing in an oxidizing atmosphere. It is generally assumed that the blisters are the fault of the metal itself, and are caused by careless or imperfect melting; this is asserted to be radically wrong. Experiments show that sterling silver cannot be blistered when a reducing flame is used for annealing, but an oxidizing flame produces numerous blisters. The theory is advanced that silver absorbs oxygen energetically when the temperature approaches the melting point. Slow Rusting Iron Produced in the Open-hearth Furnace. ANON. (,%a,~. News, lxiii, 6.)-“ American ingot iron” has recently been placed on the market by the American Rolling Mill Co., which exhihits a high resistance to corrosion and is therefore valuable as a structural material. Although produced by the basic open-hearth process it is closely similar to’ wrought iron. It differs from steel in that its contents of carbon, manganese, and silicon are only fractions of the amounts in ordinary soft steel. In appearance, strength, and ductility this is practically identical with wrought iron. The usual ferromanganese recarburizer is omitted and ferrosilicon, or an equivalent, is used to purify the bmath of its oxides. Aluminum is added in the ladle to carry off the gases dissolved in the fluid metal. Relative corrosion resistance. tests with sulphuric acid show that ingot iron has 40 to 60 times the resistance of steel, and 20 to 40 times the resistance of wrought iron.