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Instruments for high-frequency currents and voltages
512
CURRENT TOPICS.
Interference of R6ntgen Rays and Heat Motion.
rj. F. I. P. DEBYE.
(Ann. d. Physik, xliii, I, 49.)--Gives various calculations relating to the theory which indicates that heat motion in the atoms has an essential influence on the interference phenomena observed with R6ntgen radiation. The interference intensity decreases exponentially with respect to heat motion (a) with increasing angular distance between incident and observation direction, (b) with increasing temperature, (c) with decreasing wave-length. The exponent of the exponential function vanishes when T = o with failing null-point energy, and maintains a finite value when a null-point energy exists. The exponent is inversely proportional to the square of the wave-length. The iflterference intensity is accompanied by a dissipation intensity which is most intense where the interference intensity appears most feeble, and vice versa. The course of the praenomena can be calculated when data are forthcoming on the behavior of the specific heat as function of the temperature. A law of similarity holds as with the specific heats of monatomic bodies, according to which the course of temperature is a function of the relation of the characteristic temperature to the temperature of observation. Advances in Metallurgy of Iron and Steel. SIR ROBERT HADFIELD. (Presidential Address, Faraday Soc., June II, I914.)--This address embraced the following subjects: (I) Early metallurgy and alloys of iron and steel. (2) Ancient iron and the Delhi Pillar. (3) Faraday's experiments in 1882. (4) Early workers in scientific metallurgy. (5) French metallurgy in the eighteenth and nineteenth centuries. (6) Value of research. (7) The author's research work. (8) Metallurgy in the middle of the last century. (9) Steel alloys research. (IO) Science and practice working together. ( I I ) Development of research during the last fifty years. (12) Special steel alloys. (I3) Effect of carbon upon iron. (I4) The author's experiments on alloy tool steel. (15) Tool steel of lower carbon percentage. (16) The great work of Ledebur. (17) Allotropic theory. (18) The author's papers on alloys of iron. (19) Thermal treatment. (20) Low-temperature experiments in Great Britain and America. (21) Field for research. (22) The non-magnetic and magnetic conditions of manganese steel. (23) Melting-points. (24) Microscopy (Sorby's work as the originator of metallography). (25) Percy's work. (26) The art of scientific discovery. (27) Why research work is so valuable. (28) The work of the National Physical Laboratory. (29) Past progress in metallurgy. (30) The scope Of the University. (3 I) The Faraday Society. Instruments for High-frequency Currents and Voltages. W. H. ECCLES. (Electric~n, lxxii, IO44.)--A description of a simple hot-wire ammeter of quick period, a very sensitive electrometer of simple construction, and a convection galvanometer. All have been employed successfully by the author for high-frequency work.
CURRENT TOPICS.
Interference of R6ntgen Rays and Heat Motion.
rj. F. I. P. DEBYE.
(Ann. d. Physik, xliii, I, 49.)--Gives various calculations relating to the theory which indicates that heat motion in the atoms has an essential influence on the interference phenomena observed with R6ntgen radiation. The interference intensity decreases exponentially with respect to heat motion (a) with increasing angular distance between incident and observation direction, (b) with increasing temperature, (c) with decreasing wave-length. The exponent of the exponential function vanishes when T = o with failing null-point energy, and maintains a finite value when a null-point energy exists. The exponent is inversely proportional to the square of the wave-length. The iflterference intensity is accompanied by a dissipation intensity which is most intense where the interference intensity appears most feeble, and vice versa. The course of the praenomena can be calculated when data are forthcoming on the behavior of the specific heat as function of the temperature. A law of similarity holds as with the specific heats of monatomic bodies, according to which the course of temperature is a function of the relation of the characteristic temperature to the temperature of observation. Advances in Metallurgy of Iron and Steel. SIR ROBERT HADFIELD. (Presidential Address, Faraday Soc., June II, I914.)--This address embraced the following subjects: (I) Early metallurgy and alloys of iron and steel. (2) Ancient iron and the Delhi Pillar. (3) Faraday's experiments in 1882. (4) Early workers in scientific metallurgy. (5) French metallurgy in the eighteenth and nineteenth centuries. (6) Value of research. (7) The author's research work. (8) Metallurgy in the middle of the last century. (9) Steel alloys research. (IO) Science and practice working together. ( I I ) Development of research during the last fifty years. (12) Special steel alloys. (I3) Effect of carbon upon iron. (I4) The author's experiments on alloy tool steel. (15) Tool steel of lower carbon percentage. (16) The great work of Ledebur. (17) Allotropic theory. (18) The author's papers on alloys of iron. (19) Thermal treatment. (20) Low-temperature experiments in Great Britain and America. (21) Field for research. (22) The non-magnetic and magnetic conditions of manganese steel. (23) Melting-points. (24) Microscopy (Sorby's work as the originator of metallography). (25) Percy's work. (26) The art of scientific discovery. (27) Why research work is so valuable. (28) The work of the National Physical Laboratory. (29) Past progress in metallurgy. (30) The scope Of the University. (3 I) The Faraday Society. Instruments for High-frequency Currents and Voltages. W. H. ECCLES. (Electric~n, lxxii, IO44.)--A description of a simple hot-wire ammeter of quick period, a very sensitive electrometer of simple construction, and a convection galvanometer. All have been employed successfully by the author for high-frequency work.