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Fiii. 405.

Fig. 404. Another photograph, fifty-four diameters magnification, of a filling that has shrunk
away from the wall of the cavity. a. The amalji;am. «. The steel tube. The space between the
two shows the shrinkage as it appears with a half-inch lens in the microscope. The scale at the right
is a micrometer scale, which divides one millimeter into one hundred parts, which was placed on the
stage plate and photographed without changing the camera after photographing the amalgam in the
tube.
Fia, 405. A photograpli from another filling in a steel tube very similar to that shown in Figure
4114. A. the amalgam. n. The steel tube. The scale is also attached. Such shrinkages as these
ai'e conuiiou to aimealed amalgams couiiiused of silver i'lid I in. varying fnim fift\' to sixty-five per cent
uf silver, .\dding gold, platinum or copper gives but littli iliangc in the results.