Intensification of the Metallic Image in Gerlach and Stern's Magnetic Experiments

Abstract

IN the course of some attempts to measure the magnetic moment of the cadmium atom by a slight modification of Gerlach and Stern's original arrangement, a new method of intensifying the effect of a deposit of a very small number of metallic atoms on glass has been used, which although perhaps rather obvious has not, so far as I can ascertain, been employed for this purpose before. In Gerlach and Stern's first experiments on the silver atom a chemical method of rendering the deposit of atoms on the glass plate visible was used. In their later experiments on other metals it was found that in certain cases the deposit was visible without intensification, but in others it had to be developed by the same means. It is, however, plain that the use of comparatively huge quantities of liquid when dealing with a metallic deposit which may be at the most on the average only one molecule thick is dangerous, as solution of the deposit might easily occur. The method now to be described avoids this difficulty and is also probably easier to work. It depends on the fact that, while cadmium vapour at low pressures will not condense on a clean glass surface at ordinary temperatures, it does so readily at liquid air temperature. If, however, the smallest deposit of cadmium is already present on the glass, the vapour will condense on it at ordinary air temperature, quickly forming a visible deposit.