Recent developments in cathode-ray oscillographs

The paper deals briefly with some of the more important developments in design and use of cathode-ray oscillographs. Methods of increasing the photographic or recording sensitivity are first considered, particular attention being given to (a) focusing the cathode-ray stream, (b) increasing the sensitivity of the photographic film, (c) the use of phosphorescent materials as a means of increasing photographic sensitivity and of facilitating ¿external¿ photography, and (d) increasing the exciting voltage and consequently the kinetic energy andpenetrating power of the cathode rays. With regard to (d), particular a ttention is paid to Lenard´s observations on the penetrating power of high-velocity cathode rays and the application of his results to the design of high-voltage oscillographs fitted with a ¿window¿ for direct external photography. Referring to the technique of recording by cathode rays, consideration is given to the various methods of generating a ¿time¿ axis and to methods of voltage subdivision. The paper concludes with a section dealing with the recording of isolated electrical impulses.