6 BULLETIX 322, U. S. DEPARTMENT OE AGRICULTURE. 
are present in domestic unretted flax straw. For this reason alone 
flax straw would require the use of more chemicals in its reduction 
than does flax waste. 
(2) The proportion of wood in flax straw is far higher than in flax 
waste, which probably would necessitate a higher consumption of 
chemicals in treating the former. If it should appear necessary to 
exclude wood shives from the finished product, it might be found 
necessary to reduce the wood to a greater extent than when using 
flax waste, in which case the reduction might require the employ- 
ment of a higher steam pressure or a longer time of treatment, or 
both. 
The greatest difference in a physical sense between straw and 
waste is that the former, being composed of lengths of the whole 
stalk, presents larger pieces, or masses, to the action of the chemi- 
cals, thus necessitating the employment of more time in the chemical 
reduction process. These chemical and physical differences, how- 
ever, do not differ in kind but only in degree, from which it would be 
concluded that the method found to be satisfactory with straw would 
differ in no fundamental manner from that known to be satisfactory 
with waste. 
LABORATORY EXPERIMENTAL TESTS ON THE PREPARATION OF PULP. 
In March, 1914, preliminary work was started by the Department 
of Agriculture on the utilization of flax straw as a raw material* for 
sack or wrapping paper manufacture. It was decided that, of all the 
fiber-treating processes, the milk-of-lime process was the most worthy 
of trial, after the following factors, among others, had been con- 
sidered carefully : 
Lower initial cost of factory installation, — On account of freight rates, which 
figure so prominently in the final costs of manufactured products, and because 
of the remoteness of the flax region from paper mills, it might appear advisable 
to establish pulp or paper mills nearer the source of raw-material supply. It 
would be inadvisable to install a process which demands a heavy expenditure 
per ton, such as the soda, sulphate, and sulphite processes, before the true 
value of the material were proved by actual manufacture for a reasonable 
period of time. Such a practical test might be prohibitive because of the 
shipping cost for such a distance, and few, if any, manufacturers could be 
expected to operate at a loss or even at a low profit for a sufficient period to 
determine the advisability of factory installation. The same remarks apply 
to the milk-of-lime process, but not to the same degree. 
Tensile strength of the fibers preserved. — As is commonly known, caustic soda 
pulping lowers the tensile strength of fibers more than the milder milk-of-lime 
process. 
Class of employees required. — The milk-of-lime process does not demand the 
employment of as large a staff or as great a variety of skilled help as the soda, 
sulphite, or sulphate processes. 
