Page 320 - My FlipBook

318 PLASTIC FILLING MATERIALS.

ratio is equal parts by weight of liling.s and iiier-
curv. When a mortar is used for niakiug the amal- iMfl. i!si.
gam, one of glass and having a glass pestle (see
Figs. 280, 281) is to be preferred. Mixing in the
palm of the hand is a dirty process, the hand and
fingers becoming much discolored by the metallic
oxids.
Fig. 280.

Glass mortar. Glass pestle.
A rubber mortar (Fig. 282) to be received in the palm of the hand
has been devised by Dr. Genese. In view of deductions from Dr.

Fig. 282.

Dr. Genese's rubber mortar.

Black's experiments this latter method of mixing is regarded as usually
the preferable one.
The filings are placed in the receptacle, the mercury is added, and
the mass is triturated—if in a mortar, by the pestle, if in the rubber
basin, by the forefinger guarded by a rubber finger-stall. When the