264 Practical Paper-Making. 
permit them to employ a larger proportion of starch, with- 
out thereby increasing the adhesiveness of the leaves. 
Taking the practice of the Chinese as a starting point, they 
were in the hopes of success. Experience confirmed their 
conjectures; but, as they were operating with fermented 
pulp, the paper, although impermeable, had not enough 
stiffness to make the sizing appear satisfactory. The com- 
missioners thought that the process would not succeed 
completely with any but unfermented pulp. The follow- 
ing was their method of operating :— 
When the trituration was complete, and the pulp had 
atrived at that point when it only remained to add the 
blueing, they poured into the rag-engine two buckets of a 
size, made of starch and alum. When the mixture was 
complete, they gradually added a solution of resinous soap, 
made with subcarbonate of soda instead of the caustic 
potassa, used by Braconnot. This soap was added in 
sufficient quantities to dissolve the alum. The action of 
the cylinder produced a great deal of foam, which disap- 
peared on the addition of a tumblerful of oil. 
With a view to giving greater stiffness to the paper, they 
added clarified animal size. The paper peeled somewhat, 
after being pressed without the felts; but this evil was 
remedied by pouring into the rag-engine a small amount 
of a solution of white soap, and the leaves could then be 
stripped off without peeling at all. Animal size did not 
seem to them to be necessary, nor is it employed by M. 
Canson, as will be seen hereafter. 
It appears to usimportant to describe the manner in 
which the commissioners prepared their resinous soap. To 
a solution of subcarbonate of soda they added resin, until 
it refused to combine any farther. They at once dissolved 
this soap in hot water and poured it into a barrel; the un- 
combined resin precipitated, and the solution gelatinized 
on cooling. By this precaution they made themselves sure 
of using an exact mixture of alumina, resin, and starch, 
which they then precipitated around the molecules of the 
pulp, as equably as possible. 
The commissioners think that it would be better to treat 
the pulp first with alum, and then to mix a little caustic 
soda with the water in which the starch is dissolved, on ac- 
count of the property, recognized as belonging to caustic — 
alkalies, of converting the starchy particles at once into 
size. The succeeding boiling renders the size still more 
fluid. The soap is now added, and when the materials are 
