Abstract
Several air-lock methods have hitherto been devised for vacuum apparatus such as, electron microscope and electron diffraction camera with the intention of saving the time of evacuation and also minimizing the contamination in changing specimens or dry plates-Yet, either the troublesome manipulation of pre-evacuation or the smallness of room for accommodating needed accessory or the risk of contamination of specimen by grease caused inconvenience. The new method is comprised in that two cylindrical rods of equal dia-meters, one with a projecting center piece at one end holding the specimen and the other with a cylindrical hole drilled axially to cover the projection, make one complete cylindrical rod when the two are joined together. The two rods are placed opposing with each other through Wilson seals on the walls of the apparatus so that, by joining the rods, the joint can be pushed in and out of the apparatus without disturbing the vacuum enabling the specimen to be changed when the joint is outside. A specimen holder for electron diffrac-tion camera is made on this principle with which diffraction patterns are obtained by both transmission and reflection with ease and the specimen can be changed without difficulty.
