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Agitation by air and steam
CURRENT ToPics.
8I
Changing the Color of the Diamond. PAuL SACERDOTE. (Comltes rendus, I49.)---The author's results in a number of experiments on colorless and yellowish diamonds are: (I) The X-rays do not change the color of the diamond perceptibly, (2) The cathode rays of a vacuum tube changed the appearance of the diamond placed within the tube from colorless or pale yellow to the color of " Madeira wine" and finally to a more or less pronounced brown, dependent on the length of exposure. ( 3 ) This color is permanent and unaffected by direct sunlight. (4) A temperature of 300 ° tO 4oo ° C. removes this coloration.
Physiological Effects Produced by an Alternating Magnetic Field. S. P. THOMPSON. (Comptes rendus, cl, I6.)--Up to the present time it has been admitted that magnetism produces no physiological effect; it has been positively stated that if one's head is placed between the poles of a powerful electro-magnet, one feels no effect. However, by operating in an alternating field of sufficient force, a positive action is obtained, which was perceived by all who underwent the experiment. The field was produced by a coil of 32 turns of a copper wire, large enough to carry about i8o ampbres ; the coil was 8 inches long and 9 inches in diameter. The rate of the current was 5o per second. The ma:~imum value of the field was 14oo units C.G.S. at the centre. On placing the head in this coil an observer perceived, in the dark or by closing the eyes, a weak and fluctuating light, either colorless or slightly bluish. The period of fluctuation is badly defined; and is more brilliant at the periphery than at the centre. Even in full daylight, with the eyes open, there is a sensation of a luminous fluctuation. These effects increase or diminish with the intensity of the electric current. The senses of hearing and smell are unaffected. Taste is affected in the same way as sight. Agitation by Air and S t e a m . (Power, xxxii, i 9 . ) - - I n some metallurgical operations steam is admitted to large tanks to produce agitation. In certain cases the consumption of steam is enormous and the quantity of steam can be greatly reduced and the agitation much increased by allowing the steam to carry in air through an injector. First turn on the steam, then open the valve of the injector until the desired amount of air is obtained.
Controlling a Ship's Water-tight Bulkhead Doors.. (Engineering, lxxxix, 2313.)--The Stone-Lloyd system of controlling such doors by hydraulic power is becoming widely employed, owing chiefly to the absence of expense for upkeep and repair. This system is to be adopted in the large trans-Atlantic steamer La France and in the new Japanese dreadnought now building at Yokosuka. This vessel has 22 doors. The Japanese authorities accept the contention of the owners of the Stone-Lloyd system that hydraulic
8I
Changing the Color of the Diamond. PAuL SACERDOTE. (Comltes rendus, I49.)---The author's results in a number of experiments on colorless and yellowish diamonds are: (I) The X-rays do not change the color of the diamond perceptibly, (2) The cathode rays of a vacuum tube changed the appearance of the diamond placed within the tube from colorless or pale yellow to the color of " Madeira wine" and finally to a more or less pronounced brown, dependent on the length of exposure. ( 3 ) This color is permanent and unaffected by direct sunlight. (4) A temperature of 300 ° tO 4oo ° C. removes this coloration.
Physiological Effects Produced by an Alternating Magnetic Field. S. P. THOMPSON. (Comptes rendus, cl, I6.)--Up to the present time it has been admitted that magnetism produces no physiological effect; it has been positively stated that if one's head is placed between the poles of a powerful electro-magnet, one feels no effect. However, by operating in an alternating field of sufficient force, a positive action is obtained, which was perceived by all who underwent the experiment. The field was produced by a coil of 32 turns of a copper wire, large enough to carry about i8o ampbres ; the coil was 8 inches long and 9 inches in diameter. The rate of the current was 5o per second. The ma:~imum value of the field was 14oo units C.G.S. at the centre. On placing the head in this coil an observer perceived, in the dark or by closing the eyes, a weak and fluctuating light, either colorless or slightly bluish. The period of fluctuation is badly defined; and is more brilliant at the periphery than at the centre. Even in full daylight, with the eyes open, there is a sensation of a luminous fluctuation. These effects increase or diminish with the intensity of the electric current. The senses of hearing and smell are unaffected. Taste is affected in the same way as sight. Agitation by Air and S t e a m . (Power, xxxii, i 9 . ) - - I n some metallurgical operations steam is admitted to large tanks to produce agitation. In certain cases the consumption of steam is enormous and the quantity of steam can be greatly reduced and the agitation much increased by allowing the steam to carry in air through an injector. First turn on the steam, then open the valve of the injector until the desired amount of air is obtained.
Controlling a Ship's Water-tight Bulkhead Doors.. (Engineering, lxxxix, 2313.)--The Stone-Lloyd system of controlling such doors by hydraulic power is becoming widely employed, owing chiefly to the absence of expense for upkeep and repair. This system is to be adopted in the large trans-Atlantic steamer La France and in the new Japanese dreadnought now building at Yokosuka. This vessel has 22 doors. The Japanese authorities accept the contention of the owners of the Stone-Lloyd system that hydraulic