June, I944.1 CURRENT TOPICS. 5o9 which were undreamed of formerly, and it has greatly simplified many measurements previously made in a cumbersome or expensive fashion. Electronic instruments are becoming more and more prominent in their contributions to our store of knowledge, as daily they are permitting engineers to design and build better and less expensive products.
Excessive vibration is destructive to high-speed rotating machines, such as propulsion equipment for destroyers and submarines, and superchargers for aircraft. The engineer must be able to measure accurately the degree of vibration and to make corrections of weight distribution to assure smooth, prolonged operation. Vibration indicating instruments have been available for many years, but with the electronic vibration velocity meter, measurement and analysis of vibrations can be made more accurately and at higher speeds. Sound measurement is another example of the contributions which dectronics has made to industrial measurements. Before the development of the electronic tube, the measurement of sound was solely by ear, without any definite standards against which to measure.
Electronic equipment has helped in many complicated industrial problems. An example of this is the analysis of gas where it is desired to have a continuous indication and a running record of gas concentrations in a furnace or a pipe line.
An electronic mercury-vapor detector has been produced to give an instantaneous indication when the degree of mercury vapor concentration in the air exceeds that which is considered harmless to human beings. This electronic instrument can literally "see" the mercury vapor, which is both odorless and invisible.
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