What Is Quantum Mechanics
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copper and iron to determine the effect of grain-size, cold work, and other physical factors, on the coefficient of internal friction and other features of the dissipation curve. 12. The emission of positive ions from tungsten at high temperatures. LLoyp P. Smiru, Cornel! University.—It has been found that a tungsten filament, after being flashed at a temperature above 3000°K and operated at 2500°K for ten hours in order to remove impurities such as alkali metals, emits positive ions. The ion current is steady and is related to the temperature of the filament by the relation—i, =AT%e~*7. It’s magnitude at 2500°K is about 6.6 X 10-* amperes per square cm of emitting surface. The mass of the ions could not be determined by using the principle of the Hull magnetron with a collecting cylinder 3.2 cm in diameter and an axial magnetic field of 5000 gauss, under a difference of potential of 20 volts between the filament and cylinder. This shows that the mass of the ion is greater than that of a potassium ion. Theoretical considerations indicate that the ions are produced in the tungsten and may be tungsten ions. The ion current at a given temperature remains unchanged when an inactive gas such as argon is admitted to the tube provided its density does not become great enough to appreciably cool the filament. 13. Arcs with small cathode current density. J. SLEPIAN AND E. J. HAVERSTICK, Westinghouse Elec. & Mfg. Co., East Pittsburgh, Pa.—A theory of the cathode of an arc based on the drawing of electrons from a thermionically inactive electrode by very intense electric fields has been proposed. This field is maintained by space charge of positive ions next to the cathode, and it may be shown that this requires a current density of more than 1000 amps/cm? even at low gas pressures. carried the of arcs with current densities of less than 100 amps/cm? so that the above theory seems untenable in the case of these arcs. 10- sec. at 78° to 10-7 sec. at —19°C. In the temperature range between 78° and 10° the time constant varied as the first power of the pressure and not as the square of the pressure as predicted by the simple theory of diffusion of radiation. The values of the time constant were, however, so small that it still seems necessary to explain the persistence as due to a series of absorptions and reemissions, with possible a wave-length change at each step. The life of 1849 was found to be less than 3 X 10~* seconds. Two other radiation processes were observed, one having a life of 2 10~* seconds, excited at 7.1 volts and the other a life of about 8 x 10-5 seconds excited between 5 and 6 volts. Sound radiation from a system of vibrating circular diaphragms. the expression for the velocity potential due to a point source radiating into a semi-infinite medium Lord Rayleigh has determined the sound radiation from a vibrating circular diaphragm in an infinite wall. Following the same method, the radiation due to any shaped diaphragm or combinations of diaphragms can be determined. Curves are given for circular diaphragms showing the distribution of pressure over the surface bounding the semi-infinite medium. These curves enable the determination of the radiation from any combination of vibrating circular diaphragms placed in the surface. Calcu- lations have been carried out for a number of special cases. At low frequencies the diaphragms react upon each other to increase the efficiency of radiation. This effect vanishes at high frequencies. The mutual aid of the diaphragms decreases very rapidly as the distance between the diaphragms is decreased. results are on the basis of phase differences between the motion of a diaphragm and, the pressure over the surface of signal! shown the of the signal very variable. The variations are shown graphically upon the paper strips of a Shaw Recorder. The obtained from extrapolation the with in the atmosphere a 50 watt fields up to 50 gauss r.m.s. at 10° cycles in a coil 3/4” diameter by 2” long to modulate a constant field. Bismuth was wound bifilarly on a bakelite tube placed inside the solenoid and both im-mersed in liquid air. A single turn of copper wire around the tube served to measuring the field strength and phase. Direct current was passed through the bismuth wire, and being held constant by a radio frequency choke, an alternating voltage appeared across its terminals proportional to and in phase with its resistance. To measure this voltage in phase and magnitude a double potentiometer was constructed. The change in resistance of the bismuth wire was found to be in phase with the field and equal in magnitude to that which was calculated from d.c. measurements of resistance against field strength. The overall precision was about 5 percent. Similar work had been done at 50,000 cycles and room temperature when the effect was also found to be normal. Fields up to 700 gauss r.m.s. between dust core poles were obtained at the latter frequency. of a 312A tube, and giving to this grid a negative bias through a suitable resistance, we have obtained an amplification of 16 million. The photoelectric current was measured on a sensitive galvanometer (2X10-" amp/mm) and the corresponding tube plate current change was measured on a milliammeter. 33. Photoelectric spectro-photometer. Jos—pH RAZEK AND J. MULDER. University of Pennsylvania.—A photoelectric spectro-photometer consisting of an optical system, a photoelectric cell, and vacuum tube amplifier has been built. The amplifier comprised two vacuum tubes placed into the arms of a bridge. The sensitivity of this circuit was found to be aIg/dE, =G/[2+Re(J+1/R;) | where J and G are respectively, the plate, and the mutual conductance of the tubes, Riis the external plate resistance,and Rg is the galvanometer resistance. It was subsequently found that the same circuit has already been described by Wynn-Williams (Proc. Cam. Phil. Soc. 23, 810, (1927)) who gives a similar sensitivity expression. We have obtained a sensitivity of 500,000 mm/volt with good stability. The addition of grid resistors of proper magnitude will increase the sensitivity. The computed and measured values of the amplification agree to 1 percent, which is the accuracy to which the quantities involved were measured. The light to be examined is passed through a spectrometer into the photoelectric cell. The cell is connected to one grid in the bridge circuit. The deflection of the galvanometer is a function of the light intensity. Spectral curves of light from an arc and of light diffusely reflected from opaque objects were obtained. A portable self-recording instrument embodying these ideas is in course of construction. It is believed that this device will prove simpler than others recently suggested for the same purpose. 34. Perturbations band spectra. JENNY RosENTHAL F. JENKINS, for the deviations of the lines at the perturbations in the states m’=12 and n’’=11 of the violet CN system have been completed. They show additional examples of the resonance form previously the furnace, the arc, and the spark spectra of the rare earth group of elements found that a great many of the praseodymium spark lines, Pr II, show what may be called hyper-fine structure. Using the large solar spectrograph on Mt. Wilson, dispersion 1.5A per centimeter, one of the authors photographed some of the more prominent hyper-fine groups within the region 3900-5000 Angstroms. All of the completely resolved hyper-fine structures reveal six com- ponents. The frequency intervals between the hyper-fine structure for any one set of six lines follow very closely the Landé interval rule and the relative intensities of the lines in each group decrease with the interval. Some of these groups of lines show decreasing intervals and in-17 is, however, strong evidence that the process involves a three-body impact between a mercury ion, a normal sodium atom and an electron. This is suggested by the nature of the sodium spectrum and by the marked enhancement of the mercury lines originating at the 3°S and 3!S levels produced by the introduction of sodium vapor into the ionized mercury. There was no indication of direct electron excitation in this ap- paratus, although Rayleigh’s results indicate that this type of excitation may have been important in his apparatus. a neutral proton an electron is added. Its electromagnetic undulatory énergy would flow into the proton as a cir- cular current directed downward, of which the work on a unitary pole would be 27 x 1.6 x 10-8, The energy corresponding to this work would be distributed among the 60 levels of the proton; therefore u =2r X 1.6 X 10-*°/60 =1.7 X 10-*!, Gauss -Cm is its value appearing at the surface level of the proton as a magnetic moment, the Weiss constant. A radiation must be referred now to $u"8 since yz is the volumetric energy distributed on both sides of a level, and an oscil-lating electron would have only one degree of freedom along one dimension only of the eucli-dean space. It was found that the voltage V =ry"/* for one oscillation only. It was also found that e(ru!/*) =h =1.6 X 10-2 K3.14(1.85 K 10-2!) 3 =6.18 K 10-2, the Planck constant. the rotatorial Brownian motion of a mirror suspended a fine It follows from the theorem of equipartition that the average square deviation of the mirror will depend on the temperature alone of the surrounding gas. Gerlach verified this for a large range of pressures (1 to 10-* atm.). The analogy which we found that existed between this problem and the well-known treatment of the shot effect by Schottky, enabled us to give a more detailed theory of this phenomenon. If the displacement, registered during a time, long compared with the characteristic period of the mirror, is developed into a Fourier series, we found the square amplitude of each Fourier com- ponent to be a function of the pressure and molecular weight of the surrounding gas as well as of its temperature. The sum of those squares, however, is a fu