. The study of the velocity of electrons in the photo-electric effect, as a function of the wave-lengths of the light. g it to the tube with red sealing wax, which may have developedconsiderable gas. The plate P was also sealed on with red wax, whichmay have added to the trouble. For these or other reasons, it wasimpossible to obtain a high vacuum in the tube, or to get the metalphoto-electric. Other tubes shown in Figs. V and VI are similar to the last onedescribed. The cell shown in Fig. V has a thin sheet copper cylin-der, which has a slit in the top, through which light passes infalling up
. The study of the velocity of electrons in the photo-electric effect, as a function of the wave-lengths of the light. g it to the tube with red sealing wax, which may have developedconsiderable gas. The plate P was also sealed on with red wax, whichmay have added to the trouble. For these or other reasons, it wasimpossible to obtain a high vacuum in the tube, or to get the metalphoto-electric. Other tubes shown in Figs. V and VI are similar to the last onedescribed. The cell shown in Fig. V has a thin sheet copper cylin-der, which has a slit in the top, through which light passes infalling upon the photo-electric potassium metal C, The photo-elec-tric metal was distilled upon an iron disk at the position B. Totransfer this disk into the final position C, the top of the cylin-der is made of iron so that the cylinder may be raised or loweredby means of a magnet. The cylirder is emitted from the cell asshown in Fig. VI. Sodium potassium alloy C, which is poured intothe cell, through the glass tube T, is the metal used in this cells were not photo-electric, although carefully prepared. 14 ii i. FTC. VI. The difficulty may have been due to tha large amount of metal in thetubes which evolved some occluded gases, or to a sealing wax jointwhere the quartz plate was sealed upon the tube. These joints weremade with greatest care, so that the sealing wax inside the tube wasreduced to a minimum. Several cells, which are not shown in a diagram, were unsuccess-ful. Two rubidium cells showed some interesting features. Exposedto light they showed In the beginning considerable sensitiveness,which decayed rapidly until they did not respond even to intenselight. Ater being left in th? dark for a short time, they wouldsometimes recover. The photo-electric metal was melted several times,but a-parently was not, effective in changing the behavior of the same behavior was observed in a potassium cell. It was put insunlight for several hours, but this did not result in
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectlight, bookyear1912
