An a. c. operated mass spectrograph of the Mattauch type.
A mass spectrograph for chemical analysis of solid samples has been developed. The Mattauch arrangement of a 31° 50′ electric deflection followed by a 90° deflection in a magnetic field was used in order to obtain a large mass range in focus on one plate. The accelerating and deflecting voltages, and the current for the electromagnet were obtained from stabilized rectifier circuits connected to the 60‐cycle a.c. supply. The electromagnet with 100 milliamperes gave a field of 18,800 gauss across a ⅛″ gap. During the introduction of the plate or insertion of new electrodes a gate valve was closed to isolate the spectrograph from the pumping system. In this way different samples could be examined rapidly. The ion source was energized by a compact Tesla transformer wound on Lucite cylinders. One exposure covered a mass range from any mass M to a mass 10M.
A Vacuum‐Tight Sliding Seal
The operation and construction of a vacuum‐tight sliding seal by means of which unlimited translational and rotational motion in vacuum can be obtained is described. The seal is made by an appropriately distorted rubber gasket, and a table has been prepared which gives the dimensions of the gaskets to be used for various sizes of sliding rods.
Mathematical Time and Physical Time in the Theory Of Relativity
In the Theory of Relativity time is an imaginary quantity that can not be observed; it is a multiplication of a number that indicates duration of material change and number i that is an imaginary number. i on the square is -1. Time i⁄t is a mathematical time that describes the speed and the duration of material change. In the Universe one can observe physical time only as a stream of material change. It is not that change run in physical time, change itself is physical time.. Distinction between imaginary mathematical time and visible physical time opens some new perspectives into interpretation of Theory of Relativity. c