moodie: methods of studying fossils. 



189 



Figure 1. 



1. Apparatus for whitening dark or black fossils in order to bring out 

 details for photographic and study purposes. A foot bellows with a long 

 tube attached through which the air is forced into the reservoir a. From 

 this reservoir pass off two tubes leading through two wash bottles,, b con- 

 taining C. P. HC1, c containing C. P. NH4OH. The fumes from these 

 are carried through drying towers containing chloride of lime, d and e, to 

 take out all moisture; then the fumes are mixed at the tips of the glass 

 canuli, forming a white deposit of ammonium chloride (NH4CI) on the 

 object to be studied or photographed. 



cases are completely carbonized and crushed flat. In some 

 cases a thin carbonaceous pellicle adhered very closely to the 

 fossils, and this was difficult to remove. The Linton fossils are 

 all black, and can only be detected by close scrutiny in certain 

 lights. The important thing was to treat the specimens so 

 that the fossils would be distinct in ordinary lights. This was 

 done by an apparatus (figure 1) which deposited ammonium 

 chloride in a tenuous layer over the fossils. The apparatus 

 consists of a bellows, or a mouth tube, to blow air through the 



