Index of content:
Volume 16, Issue 3, March 1945
16(1945); http://dx.doi.org/10.1063/1.1770324View Description Hide Description
A method for the photometry of photographic flash lamps with a cathode‐ray oscilloscope is described. The circuits required to obtain curves of luminous flux versus time on the oscilloscope are given. Accurate timing is obtained through the use of beam modulation. Some of the precautions necessary to assure accuracy are discussed.
16(1945); http://dx.doi.org/10.1063/1.1770325View Description Hide Description
Two beams from an infra‐red source are focused on opposing thermocouples which are connected in series to a galvanometer. Rocksalt cells containing identical compounds A are placed in each beam, and the galvanometer is set to zero by a shunt resistance across one of the thermocouples. Then if the composition in one cell is changed by addition of another compound B, a galvanometer deflection is observed, if the integral of transmission times radiation curve is different for pure A and for mixtures of A and B. Several examples are given, showing galvanometer current as a function of composition from pure A to pure B in the second cell, while pure A is kept in the first cell. The device thus permits a simple analytical method for two component systems.
16(1945); http://dx.doi.org/10.1063/1.1770326View Description Hide Description
Small leaks in vacuum systems may be found by observing the change in temperature‐limited thermionic emission of a tungsten filament in the vacuum as oxygen is blown over the leak. An apparatus is described for regulating the filament heating power so that the emission is not affected by line voltage fluctuations. The apparatus also operates as an ionization gauge with emission control.
- LABORATORY AND SHOP NOTE
16(1945); http://dx.doi.org/10.1063/1.1770327View Description Hide Description