22 
Indian Forest Records. 
[ Vol. Ill 
The resultant pulp amounted to 49 per cent, on the original weight 
and was of a yellow straw colour. Bleaching reduced it to 46'3 per cent, 
and it required 40 per cent. B. P. (on weight of unbleached pulp) to 
bring it up to standard white. This was the best of several experi¬ 
ments and no variation in liquor contents, time or temperature produced 
any better results. Such a bleaching cost is not economically permis¬ 
sible and it seems clear that the sulphite process, even if workable in 
the tropics, has no advantages for the production of bamboo pulp. 
27. The conclusions arrived at in the Sections A and B considerably 
clear the way for both soda and sulphate treat- 
Soda process. men t. We know that for digestion of material 
which has had its mass, air and colloidal resistance nearly entirely des¬ 
troyed ( i.e ., in fine shavings), and from which the starch contents have 
been extracted, a temperature of 150° is essential for at least three hours, 
with consumption of NaOH as per Table Y : that these conditions are 
necessitated by the chemical composition of the bamboo and that anything 
required in excess of them will be due to the resistance still remaining in 
the crushed material. The extent to which such excess is permissible is 
governed chiefly by conditions of yield of cellulose and its capacity for 
bleaching. As a general rule, the more severe the digestion conditions, 
the lower the yield but the higher the bleaching economy, and to gain 
the latter it mav pay to sacrifice the former to some extent. The 
problem therefore is, to arrive at those conditions which most economi¬ 
cally balance the two. 
28. The cellulose shown by analysis exists in two forms :— the a-and 
/3-cellulose (of Messrs. Cross and Bevan). a-cellulose is that which is strongly 
resistant to alkaline solutions of any strength and temperature; 
/3-cellulose is a less resistant form which may be seriously attacked under 
drastic digestion conditions. Treatment designed to destroy the whole 
of the latter will usually result in yields of about 35 per cent. It therefore 
seems probable that /3-cellulose represents about one-third of the whole, 
and its conservation, so far as is consistent with obtaining a good bleach¬ 
ing pulp, has an important bearing upon the economic result. The influen¬ 
ces affecting its destruction are strong liquors, high temperature and pro¬ 
longed duration of digestion. The first is settled for us by the chemical 
requirements of the case and the large volume required to cover crushed 
material, so that as a rule the liquors will not exceed 12° Tw. At this 
strength its destructive effect is not serious except at very high tempera¬ 
tures. Saving of time, also, is a most important factor in the economic 
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