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Cold storage equipment
406
CURRENT T o r t e s .
is obtained by an acid dip; but this is not the case. This color is due to plunging the casting at a low red heat into cold, clean water. This good color is only obtained under the following conditions : The bronze or composition must be of good quality, and must not contain too n m c h lead, iron, antimony or other impurities. Copper ingot m a k e r s succeed in producing the beautiful rose-red color on the best grade of Lake copper ingots by the use of cold, clean water. Cold Storage E q u i p m e n t , ANON. (Times Eng. Suppl., June 28, I9I 1.)---The ammonia system requires less power than the carbon dioxide system and is better adapted for cooling by direct expansion in tubes in the refrigerating chamber. In small plants the compressors are often driven by electric motors, and in lart~e plants by suction gas plants. Atmosphere condensers, i.e., tubes cooled by exposure to air and a water spray, require 5° to 70 per cent. less water t h a n submerged condensers cooled b y water alone. The power required for the compressors is about i ~ H. P. per ton of " refrigerating capacity " per day, equivalent to about 3 H. P. per ton of actual ice-making capacity. To cool the refrigerating chamber by air currents, previously cooled, electrically driven fans are used. A 5 or 6 H. P. motor is sufficient to drive the fans for an air-cooler supplying 80,000 to ioo,ooo cubic feet of storage space. Amount of Radium in Some Uranium Ores. W. 1V[ARCKWALD and A. S. RUSSELL. (Chem. News, ciii, 277.)--The radium in a number of uranium ores was determined by dissolving in s t r o n g sulphuric acid, in which radium sulphate is soluble, and measuring the emanation evolved by means of its ionizing power. If the ratio of radium to uranium in Joachimsthal pitchblende is taken as IOO, then the ratio in thorianite is 98.I, and in African pitchblende Ioi. 5, but in autunite it varies from 20.7 to 68.o. A determination of ionium in auttmite showed that the ratio of ionium to uranium is much more uniform than that of radium to uranium, and is also relatively higher. Since ionium's mean duration of life is not less than 30,000 years, this indicates that autunite must be at least ioo,ooo years old, and the relatively, low numbers of the radium ratio cannot be explained by assigning to it a recent origin, as Soddv suggested. The facts are accounted /or by supposing that on account of its spongy structure, as compared with the very dense pitchblende and thorianite, radium and lead have been partially extracted from the mineral by water, the occlusion of helium also being very slight. The results obtained with rutherfordite support this view. Iron in Nickel. ANON. (Brass World, vii, 8, 294.)--The presence of iron in nickel makes it whiter. All nickel anodes and nickel deposits contain iron. This deposit, containing iron, although whiter than one free from iron, is more readily tarnished.
CURRENT T o r t e s .
is obtained by an acid dip; but this is not the case. This color is due to plunging the casting at a low red heat into cold, clean water. This good color is only obtained under the following conditions : The bronze or composition must be of good quality, and must not contain too n m c h lead, iron, antimony or other impurities. Copper ingot m a k e r s succeed in producing the beautiful rose-red color on the best grade of Lake copper ingots by the use of cold, clean water. Cold Storage E q u i p m e n t , ANON. (Times Eng. Suppl., June 28, I9I 1.)---The ammonia system requires less power than the carbon dioxide system and is better adapted for cooling by direct expansion in tubes in the refrigerating chamber. In small plants the compressors are often driven by electric motors, and in lart~e plants by suction gas plants. Atmosphere condensers, i.e., tubes cooled by exposure to air and a water spray, require 5° to 70 per cent. less water t h a n submerged condensers cooled b y water alone. The power required for the compressors is about i ~ H. P. per ton of " refrigerating capacity " per day, equivalent to about 3 H. P. per ton of actual ice-making capacity. To cool the refrigerating chamber by air currents, previously cooled, electrically driven fans are used. A 5 or 6 H. P. motor is sufficient to drive the fans for an air-cooler supplying 80,000 to ioo,ooo cubic feet of storage space. Amount of Radium in Some Uranium Ores. W. 1V[ARCKWALD and A. S. RUSSELL. (Chem. News, ciii, 277.)--The radium in a number of uranium ores was determined by dissolving in s t r o n g sulphuric acid, in which radium sulphate is soluble, and measuring the emanation evolved by means of its ionizing power. If the ratio of radium to uranium in Joachimsthal pitchblende is taken as IOO, then the ratio in thorianite is 98.I, and in African pitchblende Ioi. 5, but in autunite it varies from 20.7 to 68.o. A determination of ionium in auttmite showed that the ratio of ionium to uranium is much more uniform than that of radium to uranium, and is also relatively higher. Since ionium's mean duration of life is not less than 30,000 years, this indicates that autunite must be at least ioo,ooo years old, and the relatively, low numbers of the radium ratio cannot be explained by assigning to it a recent origin, as Soddv suggested. The facts are accounted /or by supposing that on account of its spongy structure, as compared with the very dense pitchblende and thorianite, radium and lead have been partially extracted from the mineral by water, the occlusion of helium also being very slight. The results obtained with rutherfordite support this view. Iron in Nickel. ANON. (Brass World, vii, 8, 294.)--The presence of iron in nickel makes it whiter. All nickel anodes and nickel deposits contain iron. This deposit, containing iron, although whiter than one free from iron, is more readily tarnished.