ETHYL ALCOHOL FROM WOOD WASTE. 43 
In cook No. 30, with an original ratio of water to wood equal to 
1 to 1, the ratio increased to 1.62 to 1, an increase of 62 per cent. In 
cook No. 34, with an original ratio of 1.25 to 1, the ratio increased to 
1.86 to 1, an increased of 61 per cent, which was practically identical 
with that of cook No. 30. In both cooks the yields of total sugars, 
percentages of total sugars fermentable, and yields of alcohol were 
practically identical, as shown in the table of results on series IV, 
page 36. It seems, therefore, that if there is sufficient water to 
insure a good mixture of the catalytic agent with the wood, both the 
water and acidity of the solution added are without effect; and that, 
of these two variables, the only one affecting the yields is the con- 
centration of the catalytic agent based on the amount of dry wood 
present. 
Increasing the concentration of the catalytic agent caused increased 
yields of total sugars up to about 1.5 per cent of sulphuric acid; then 
the yields begin to decrease, although the portion of the sugars that 
is fermentable increased without a break in the curve. The increase 
in the amount of sugars fermentable is sufficient to offset the decrease 
in total sugars, and consequently the resulting alcohol yield is prac- 
tically constant. The explanation of this condition, as shown on 
pages 30 to 33, is that the nonfermentable sugars (the pentoses) are 
the more unstable under the conditions used, and pentose decompo- 
sition takes place with increasing amounts of the catalytic agent. 
This pentose decomposition accounts for a decrease of the total 
sugar yield and an increase of the fermentable sugars, especially if 
there is little or no hexose decomposition; and the result is a practi- 
cally constant alcohol yield similar to that obtained. As in the 
inversion of cane sugar in the presence of an acid, here also the speed 
of the reaction is probably determined by a combination of the 
catalytic effects of both the hydrogen ions and the non-ionized acid; 
moreover, the increased amounts of sugar formed with increased 
acid concentration may in part be a result of the non-ionized molecule. 
However, this is not the full explanation of the conditions observed. 
If it were, the 4 per cent acid series should give yields as much 
greater than those of the 2.5 per cent acid as the 2.5 per cent acid 
yields are greater than those of the 1 per cent; but this is not the 
case. 
The above discussion has been limited entirely to the results of the 
experiments on spruce. Only two cooks were made on shortleaf 
pine, and these were insufficient to warrant any conclusions, especially 
in view of the complex nature of the raw material. 
