The Design of Optical Munitions of War

Abstract

IN a paper read before the Optical Society in January last,¹ Lt.-Col. A. C. Williams, the officer until lately in charge of the inspection of optical munitions at Woolwich, described in some detail the tests made by his department when inspecting the various optical instruments submitted by the manufacturers. The precedent thus set is a most useful one. It is common knowledge what an immense number of instruments were made and accepted, but it is not so generally known how stringent were some of the tests. Col. Williams makes no apology for the stringency of these tests, and in stating the conditions of service shows how different Army conditions are from those of civil life. They are indeed severe. “It must be remembered that Service instruments may be sent to any part of the world, and must remain serviceable when used in Arctic snows, Flanders mud, Mesopotamia heat and desert sandstorm, or after travelling in lorries for thousands of miles over bad roads. In some cases they are attached to guns, and have to withstand the shock of firing. It must also be remembered that they are not always used by men accustomed to handling delicate instruments, and that it is only on rare occasions that they can be sent to a workshop for repair.” In addition to these considerations, that of weight is always present. As Mr. J. W. French in his interesting contribution to the discussion points out, it is easy to make an instrument to withstand severe shock tests if lightness is not of importance.