ETHYL ALCOHOL FROM WOOD WASTE. 
41 
fermentable sugars increases. As a result the total yield is not 
appreciably lessened and the alcohol yield remains practically con- 
stant. 
In this series is seen again the importance of complete data; that 
is, data on total sugars, percentage of total sugars fermentable, and 
alcohol yields. All of these are necessary for a proper interpretation 
of the results, especially in an experiment like this, in which there is 
an apparent neutralization of two factors that vary in different ways. 
A study of these two variables — namely, the ratio of water to wood 
and of acid to wood — shows that they are not mutually dependent, 
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f4 16 18 20 22 
YIELD OF TOTAL SUGARS IN % 
OF DRY WEIGHT OF WOOD 
45 50 55 60 65 70 
°/ 0F TOTAL SUGARS, FERMENTABLE 
FlG. 
.—Series V and Va, showing variation in yields of total sugar and percentage of total sugars that is 
fermentable with varying concentrations of sulphuric acid for spruce and shortleaf pine. 
that the acidity of the solution used for hydrolysis is of minor or no 
importance, but that the concentration of the catalytic agent ex- 
pressed in percentage of dry wood is the decisive factor. As stated 
previously, Simonsen expressed all of his results in total sugar. When 
such long cooking periods are used (two hours in his work on variable 
No. 3 — the influence of the amount of water present and of the acid 
concentration), it is not surprising that he found variable sugar 
yields with a constant amount of acid and varying amounts of water, 
or varying " acidities," as he called them. The decomposition prod- 
ucts so obtained would be largely reducing agents, formic and 
laevulinic acids, which would show high sugar yields. Practically 
always, especially in the above work on cellulose, Simonsen used 
amounts of water which were technically not feasible. Neuman 
realized the technical importance of decreasing the ratio of water to 
wood, but carried it no further than 3 to 1 — 300 per cent of water. 
