6 BULLETIN L203, U. S. DEPARTMENT OF AGRICULTURE. 
more convenient and requires less labor than the burning of straw. 
However, burning straw apparently gives a greater yield of the de- 
sired gases, owing to t lie fact that a high temperature can be obtained 
in a shorter time, the length of time for carbonization is shortened, 
and the added expense for piping, burners, and mixers is made un- 
necessary. On the other hand, a greater quantity of heat is lost when 
straw is burned as fuel than when gas is used. 
LIQUEFYING AND COMPRESSING STRAW GAS. 
The liquefaction of straw gas (as a simple gas) by means of com- 
pression and a very low temperature is not successful in the labora- 
tory on account of the different gases involved. Hydrogen must be 
liquefied separately, and several of the other gases freeze during the 
process. Obviously, the liquefying of straw gas, as either a simple 
or a complex gas, is not feasible, least of all on the farm. 
Straw gas can be compressed at ordinary temperatures for storage 
as a gas in suitable tanks. The compression of this gas on the farm 
is not practicable, however, on account of the added expense and the 
necessity of securing the services of a person thoroughly familiar 
with the technique of compressing operations and with the many 
precautions which must be observed. For example, care must be 
taken to compress the gas to its ultimate pressure only in a suit aide 
number of operations, to properly cool the gas and compressors, and 
to maintain the proper lubrication of the compressor. 
STRAW GAS FOR AUTOMOTIVE POWER. 
Straw gas has possibilities as a fuel for propelling automotive 
vehicles, but under present conditions it is improbable that it 
will be used to any extent in such a manner. Automobiles have 
been operated on this gas carried in a flexible, impervious bag at- 
tached to the car. A bag containing 300 cubic feet of gas held a 
supply sufficient to run the car for 15 miles. This method, however, 
is unsatisfactory. and impracticable* 
USE OF BALED STRAW. 
Charging the retort with baled straw would facilitate its handling, 
expedite several operations, and make possible a more compact 
retort. On the other hand, baling would doubtless cost from $2 to 
$3.50 per ton of straw, more time would be required to completely 
carbonize baled straw, and the quality of the gas produced would 
probably be lower, owing to the fact that the heat penetration would 
not be as uniform as when loose straw was carbonized. The maxi- 
mum production of the desired inflammable gases seems to prevail 
when the temperature of distillation is rapidly raised. 
VALUE AND UTILIZATION OF BY-PRODUCTS. 
At present the by-products from the destructive distillation of 
straw and similar material apparently have no commercial value. 
Although the carbon residue, which can be readily powdered to 
a line consistency, can be used satisfactorily in the manufacture of 
