Practical Paper-Making. 205 
very intimately united, they are gradually poured upon the 
previously aluminated pulp, until complete saturation is ob- 
tained, which is indicated by test paper. Lastly, a solution 
of white soap is poured into the vat, and if this should 
occasion bubbles during the motions of the vatman in 
forming the paper, they may be made to disappear by the 
addition of a little oil, or still better, of an oleaginous 
emulsion. Nut or poppy oil should be preferred, on account 
of their drying qualities. 
Although they succeeded in making size with wheat 
flour, yet the commissioners advise the use of rice flour, 
in imitation of the Chinese. The proportions should vary 
and be regulated by the quality of the pulp which may 
contain more or less gluten. Experiments ona small scale, 
which any intelligent manufacturer may make without 
difficulty, will establish the proportions to be employed. 
In employing this process, we are not able to azure the 
paper with Prussian blue, as that substance is decomposed 
by the alkali of the soap. Cobalt blue should be used, and 
dissolved with the starch when the size is prepared, as in 
this manner, being closely blended with the dressing, it is 
lighter, and does not fall to the lower surface of the leaf, 
as occurs in the case of English paper. 
Moreover, cobalt blue, which is employed in Holland 
and in England, is a more brilliant and a faster colour than 
Prussian blue. 
M. D’Arcet, being at Cusset in the paper-mill of M. 
Bujon, at the time of the publication of M. Braconnot’s dis- 
covery, successfully repeated the experiment at that place ; 
but not finding the paper sufficiently sized, concluded after 
a comparative examination of the shade produced with 
iodine, that the proportion of starch required to be in- 
creased and advised the adoption of the following :— 
100'00 parts of dried pulp, 
12°00 ¥ starch, 
1‘0O a resin, dissolved in 
O'50 ; subcarbunate of soda, 
315°00 < water. 
The water was first boiled, and the soap, the resin, and 
the soda added. The boiling was continued until the com- 
bination of these materials was complete, and the starch, 
previously mixed with cold water, poured in. The whole 
was then boiled, until it became as transparent, as very 
fluid, freshly-made soap. 
This composition was poured, warm, into the rag-engine, 
