382 Walton—On a New Method of investigating Fossil 
consisting of branching filaments (PL IX, Fig. 1). The hairs arose principally 
from the surface of the veins. To check this observation, specimens from 
different localities were examined and the same features were again apparent. 
I found one specimen in which the surface of the fossil was concave and had 
not the smooth appearance so characteristic of the majority. On examina¬ 
tion of the unexposed surface by the transfer method I found it to be 
smooth and free from emergences. The dull appearance of the specimen 
was due no doubt to the fact that the hairs detached by the splitting of the 
block left irregularities on the surface, which was in this example the under 
surface of the frond. 
Method of Transfer. 1 
3. A block or chip bearing a representative portion of the fossil is 
taken from the specimen by chipping or cutting and roughly trimmed. If 
the surface of the sample on which the fossil o.ccurs is very uneven it should * 
be levelled as much as possible by scraping or cutting without injuring the 
plant. 
2 . A glass slide of suitable size is chosen, and sufficient balsam of the 
consistency of treacle is put on at one end of the slide. The slide is then 
placed on a metal plate heated by a Bunsen burner, and the balsam is 
slowly ‘ cooked ’ without being allowed to boil, to remove volatile con¬ 
stituents, until a sample drawn out between the points of a pair of forceps 
is brittle when cool. The balsam is better overcooked than undercooked. 
3. The sample is then placed face downwards on the hot plate for 
a moment, so that the surface showing the fossil may be heated. It is then 
placed face downwards on the cooked balsam at one end of the slide, and 
the slide removed to a cooler portion of the plate. It may be found that 
bubbles of air have formed between the fossil and the slide, and it will 
require manipulation to get rid of them. 
4. The preparation is cooled in air ; rapid cooling in water causes the 
balsam to crack. The balsam should set hard and brittle. 
5- The rough excess of rock is then ground off from the back of the 
sample on a glass plate with some abrasive such as carborundum, care being 
taken not to grind too near the fossil. 
6. The slide is dried, the exposed surface of the rock moistened with 
water, and the whole slide dipped into melted paraffin wax. It is then 
cooled in water and a second artd third coat put on in the same way. By 
cutting round the edge of the rock with a knife the wax can be removed 
completely from the back of the rock, as it does not stick to the wet 
surface. 
7. The slide, with all the glass portion thus covered with wax, is then 
1 In certain details this method resembles that used by Wiman in the investigation of Grapio- 
ites. See Wiman (1895). 
