In an attempt to determine the amplitude of vibration of the ions in a quartz lattice brought about by piezoelectric oscillations, a series of Laue photographs have been made of both Curie and thirty-degree-cut plates, using the white radiation from a Coolidge universal tube. This tube had a tungsten anode and carried a current of four milliamperes at 95 kilovolts. Eastman duplitized x-ray film was used with no sensitizing screens. On examination, the patterns produced by each plate, oscillating and non-oscillating, appear identical except in one respect; the pattern of the oscillating plate is several times as intense as that of the non-oscillating. A four-hour exposure of a non-oscillating plate to radiation of the above mentioned type, produces but the rudiments of a pattern, whereas, the same plate oscillating produces a very beautiful intense pattern for the same time of exposure. The effect does not depend on the mode of vibration but does depend on the amplitude. Further work is in progress which it is hoped will establish the cause of this peculiar intensity difference.

No abstract

A brief review is given of the use of photographic plates for the recording of electrons. Photographic plates are rendered more sensitive to the action of electrons by the application of a small amount of certain oils; but whether oiled or not, photographic plates are insensitive to the action of electrons when they strike the plate with a speed of less than 25 equivalent volts. This work indicates that the sensitizing action of oil is largely due to cathodo-luminescence of the oil, and that the failure of the photographic plate to record low speed electrons is due to the high electrical resistance of the photographic emulsion. Announcement is made of the discovery of the fact that metal surfaces are affected by electron bombardment in such a way that the bombarded regions react differently toward certain vapors than do the unbombarded regions. This effect has been observed even when the speed of the impinging electrons was only 12 equivalent volts. Experiments on silver and gold are presented in detail, and the practical use of the effect for electron recording demonstrated. Possible causes of the effect are also discussed. When the two methods for recording electrons are compared, it is found that the photographic method has the advantage of speed and ease of reproduction; while the metal method has the advantage of reliability, freedom from charging up, and insensitivity to light. Moreover, the metal method can be used for lower speed electrons than can the photographic method.

A portion of a metal surface was protected by means of a stencil during exposure in air to 100 kilovolt cathode rays. An attempt was then made to ``develop'' an image of the stencil on the metal surface by the action of some chemical or other reagent. Results confirm previous reports that water vapor is helpful if not essential to satisfactory development. On the metals, silver, copper, tin, zinc, lead, brass, and bismuth, the inorganic materials investigated for developing properties were superior to the organic materials tried. The image was not developed directly by electroplating by any method yet tried on any material except carbon. Attempts to produce an image in relief by first developing it in the ordinary way and then electroplating the specimen, failed except when anthraquinone was used as the developer. However, results by this method were uncertain. Cadmium vapor as a developer produces images of low relief.