56 
-RTTTF.TTX 9^3. U. 5. PEPAET^IEXT Or AGEICEXTrEE 
Three cooks were made with the use of phosphoric acid H S P0J 
a] : ne : c in mixture with sulphiric acid, and the results were as follows : 
Spnux 
iarcospberes: 125 per cad H a 
.:-- 
li-.i'-r.. 
Total 
(per cent 
of ariginal 
1:7 — • ■:•■:•! 
Pet sent :: 
total sqgazs 
ferneri- Per sent ::' 
aide. irijizil 
ir - in xL 
Saltans 
t ei : '- . 
1 : 
L8per sent :: snlphnrie aeid, 0.1 per : 21.12 - .39 
cent of 1 hospb*] tie acid. 
:.. : pa :t:_: of H-O4, 0.9 per ceni of 30. S3 55.20 
H PO* 
-i ^- --— --'H^? \ . ISL3S '" r * 
" 
is :: 
The above results are even better than were to be expected, if the 
relative degrees of dissociation of the two acids are considered. The 
slight increase in yield of cook Xo. 100. containing 0.1 per cent of 
phosphoric acid in addition to 1.8 per cent of sulphuric acid, as com- 
pared with cook No. 34 p. o5^, . containing 1.8 per cent of sulphuric 
acid only, is not sufficient when its cost is considered to warrant the 
commercial use of even small quantities of phosphoric acid. Phos- 
phates, of course, are necessary for yeas: grc wth: and if they are pres- 
ent in considerable quantities in the mash during fermentation they 
act as a yeast stimulant. It has not been found necessary, however, 
to add any great quantity of phosphates in order to secure satisfactory 
fermentation. A pound or two of ammonium phosphate or a pint 
of •"sirupy"' acid added to the starting yeast in the early stages of its 
propagation is sufficient to insure vigorous growth. 
STUDY OF DIFFERENT SPECIES. 
All the ec :xs in this series were made under the following condi- 
fabns: 2.5 per cent of sulphuric acid: 125 per cent of water: 7.5 at- 
mospheres of pressure: 20 minutes cooki ng period. The results ob- 
tained divide the different species into their natural botanical classi- 
fications, namely, the coniferous and broad-leaved species. Although 
not all species in each class were tested, authentic samples of enough 
species were used to demonstrate the value of most of those w: ; if 
that are commonly available for this process. 
