Franklin's Discovery of the Electron

In celebrating the anniversary of the discovery of the electron, it is a mistake to concentrate attention solely on J. J. Thomson's paper of 1897. I do not in any way underestimate the importance of that paper in bringing about general acceptance of the electron theory of matter, through the evidence presented in it for the existence of a charged particle of mass about 1/1000 the mass of the hydrogen atom. However, to this particle Thomson gave the name ''corpuscle," rather than electron, doubtless because the word "electron" had already been assigned by G. Johnstone Stoney to the hypothetical atom of electricity, that is, of electric charge, whether that charge is positive or negative. The existence of this atom of charge, or of the atomic constitution of electricity, was asserted with great clarity by Benjamin Franklin because of experiments begun in 1747, so that 1947 is both the 200th anniversary of Benjamin Franklin's discovery of the existence of an a tom of electric charge and the 50th anniversary of J. J. Thomson's proof of the existence of a charged particle whose mass, as he then phrased it, was about 1/1000 that of the hydrogen atom

Dependence of electron emission from metals upon field strengths and temperatures

This paper contains a full presentation of the reasons for believing, contrary to results recently obtained elsewhere, that field currents are only independent of temperature up to about 1100°K, and that at that temperature the energy of thermal agitation begins to assist the fields appreciably in causing the escape of electrons from metals. The precise form of function describing this dependence is not accurately determinable experimentally, but the form originally suggested by us fits the facts of observation thus far known satisfactorily, not better, however, than does the theoretical form suggested by Houston

On the question of the constancy of the cosmic radiation and the relation of these rays to meteorology

Mean cosmic-ray intensities have been measured with much precision both at Pasadena, California (latitude 34) and at Churchill, Manitoba (latitude 59), the latter a distance of 730 miles from the North magnetic pole. (1) The observed equality in these intensities indicates that these rays enter the earth's atmosphere as photons rather than as streams of electrons. (2) Evidence is presented that the incoming rays are of a uniform intensity in all directions and in all latitudes, the small and apparently erratic fluctuations found by many observers at different stations arising simply from eruptions, waves, or ripples which change the thickness of the atmospheric blanket interposed between the source and the observer. (3) The cosmic-ray electroscope thus acquires significance as a meteorological instrument. (4) The influence of these rays in the maintenance of the earth's charge is considered

Further experiments on the uniformity of distribution of the cosmic radiation

More careful and prolonged observations on the small, daily variation before reported in the measured intensities of the cosmic rays, the new observations being made under such conditions as to eliminate the possibility of a slight temperature effect suggested by Bowen and Millikan's recent explanation of ionization-pressure relations in high-pressure electroscopes, yield the definite result that within the limits of the author's present observational uncertainty which is of the order of a third of a percent, the sun has no direct influence on cosmic-ray intensities. New evidence is presented that if observed and apparently systematic variations of the order of a third of a percent are in fact real they are best interpreted as the result of small changes in the blanketing effect of the earth's atmosphere due to air currents

The Present Status of the Evidence for the Atom-Annihilation Hypothesis

The purpose of this paper is to present a brief review of such evidence as we have obtained in the geomagnetic studies which we have been conducting from this laboratory during the past twenty-five years for the atom-annihilation hypothesis as to the origins of cosmic rays in intergalactic space