166 PEARL SHELDON 
The blocks were compressed in a small hand vise and one or two 
of the dimensions of the blocks were often greater than the corre- 
sponding dimensions of the jaws of the vise. Little attempt was 
made to smooth the paraffin to regular shape; therefore the applica- 
tion of the pressure was often very uneven. The varying conditions 
made it possible to trace cause and effect, and, since several scores 
of blocks were compressed and each showed different effects in its 
Fic. 9.—Photograph of a block of paraffin after compression. X1.4 
different parts, the results may be taken as general for the given 
material and given conditions. 
Figs. 9 and to are photographs of two of the blocks after they 
were compressed. The pressure was applied parallel to the plane 
of the paper in a line up and down the page. These blocks were 
hardly of average value for study but they were stained so dark 
with resin that it was possible to photograph the white cracks. 
Attempts to photograph the lighter-colored specimens by trans- 
mitted light were only partly successful. Fig. 11 is a composite 
showing the more common results of compression. The pressure 
was applied over the face abcd and the opposite face. Near the 
right edge is shown the result of a fairly even pressure over a rough 
face. With even pressure and a smooth face the material would 
