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Luminous efficiency of the firefly
162
CURRENT TOPICS.
is its only drawback. Experiments were also made with calcium cyanamide. Its decomposition in the soil produces compounds Comparative experiments showed possibly injurious to vegetation. this fertilizer should always be applied some time before sowing the seed, to avoid injury during germination; and as a top dressing it must always be applied very early, that the plants may not suffer. In wet seasons calcium cyanamide seems to give better results than in dry seasons. Luminous Efficiency of the Firefly. H. E. IVES and W. W. COBLENTZ. (Bull. BUY. Stavtdurd, vi, 321.)-By photographing the spectrum of the local firefly, Photimu pyyalis, the radiation from it was shown to be limited to the yellow-green region, li 510-670. There is a maximum of intensity at 570, but the band is not composed of fine, lines. The computed luminous efficiency (light radiation) is 96.5 per cent., as against 0.4 per cent. for the carbon glow lamp. (Eng. Record, Ixi, 25.)-Concrete Concrete Floors in Vessels. floors were tried in a number of wooden vessels carrying ore and coal on the Great Lakes as a substitute for wooden floors, which suffer severely f-rom the clam-shell buckets. The concrete floors are said to stand the wear very well. Gaseous Suspensions. M. DE BROGLIE. (Physik. Zeit., xi, 33.)-Some kinds of smoke observable in gases consist of fme particles, observable in the ultra-microscope, of radius between several These shotw Brownian movements ,u ,D and several hundred ,U ,u. capable of being photographed and agreeing with a folrmula of Einstein’s. In this respect they are surprisingly like particles in liquids. They differ electrically at times in being either negative or positive or neutral, while those in liquids are never neutral. (1. Ind. Eng. Chew., i, 670.) Copper Clad Steel. W. TATTIN. -Numerous attempts have b’een made to cover stee,l with a coat of copper of any desired thickness and to weld the two m,etals so firmly that the combination could be submitted to any of the usual methods of working metals without destroying the integrity of the weld. This desired result was o’nly attained by the process to be described. Steel of any description, composition or shape is rolled into rounds and cut into 26-inch billets, to make wire rods, and is sand blasted and pickled to remove scale. The billet, drilled and tapped at each end, is hung by a rod and bushing screwed into one end in a pre-heater and brought to a red heat. The billet is then drawn into a tube by m,eans of a rod screwed into the top of the bushing. This rod slides in the centre hole of a three-jawed chuck, which holds the tube and centres the billet in it. A steel flange is then screwed on the bottom of the billet, thus forming with
CURRENT TOPICS.
is its only drawback. Experiments were also made with calcium cyanamide. Its decomposition in the soil produces compounds Comparative experiments showed possibly injurious to vegetation. this fertilizer should always be applied some time before sowing the seed, to avoid injury during germination; and as a top dressing it must always be applied very early, that the plants may not suffer. In wet seasons calcium cyanamide seems to give better results than in dry seasons. Luminous Efficiency of the Firefly. H. E. IVES and W. W. COBLENTZ. (Bull. BUY. Stavtdurd, vi, 321.)-By photographing the spectrum of the local firefly, Photimu pyyalis, the radiation from it was shown to be limited to the yellow-green region, li 510-670. There is a maximum of intensity at 570, but the band is not composed of fine, lines. The computed luminous efficiency (light radiation) is 96.5 per cent., as against 0.4 per cent. for the carbon glow lamp. (Eng. Record, Ixi, 25.)-Concrete Concrete Floors in Vessels. floors were tried in a number of wooden vessels carrying ore and coal on the Great Lakes as a substitute for wooden floors, which suffer severely f-rom the clam-shell buckets. The concrete floors are said to stand the wear very well. Gaseous Suspensions. M. DE BROGLIE. (Physik. Zeit., xi, 33.)-Some kinds of smoke observable in gases consist of fme particles, observable in the ultra-microscope, of radius between several These shotw Brownian movements ,u ,D and several hundred ,U ,u. capable of being photographed and agreeing with a folrmula of Einstein’s. In this respect they are surprisingly like particles in liquids. They differ electrically at times in being either negative or positive or neutral, while those in liquids are never neutral. (1. Ind. Eng. Chew., i, 670.) Copper Clad Steel. W. TATTIN. -Numerous attempts have b’een made to cover stee,l with a coat of copper of any desired thickness and to weld the two m,etals so firmly that the combination could be submitted to any of the usual methods of working metals without destroying the integrity of the weld. This desired result was o’nly attained by the process to be described. Steel of any description, composition or shape is rolled into rounds and cut into 26-inch billets, to make wire rods, and is sand blasted and pickled to remove scale. The billet, drilled and tapped at each end, is hung by a rod and bushing screwed into one end in a pre-heater and brought to a red heat. The billet is then drawn into a tube by m,eans of a rod screwed into the top of the bushing. This rod slides in the centre hole of a three-jawed chuck, which holds the tube and centres the billet in it. A steel flange is then screwed on the bottom of the billet, thus forming with