32 BULLETIN 1471, TJ. S. DEPARTMENT OF AGRICULTURE 
VOLUME OF HALOWAX OIL TO USE 
Experiments have shown that 4 cubic centimeters of halowax oil 
is the optimum quantity to use with a 2-gram sample of flaxseed 
meal. With this quantity of solvent this method checks the ether- 
extraction method the closest. Although 3 cubic centimeters work < 
well with some samples, with the majority this quantity is usually 
completely absorbed by the meal necessary for the test. 
TEMPERATURE AT WHICH READINGS ARE MADE 
The temperature at which reading are made should always be the 
same in order that different operators may obtain concordant results. 
This end can be accomplished by using a conversion chart or by the 
continued used of a temperature regulator. It is believed the chart 
system is preferable, inasmuch as less time is lost in making initial 
tests, because the operator does not have to wait until a specified 
temperature is reached. 
TEMPERATURE OF EXTRACTION 
The optimum temperature at which to allow the extraction to take 
place appears to be 70° C. Extracting in the cold reduces the per- 
centage of oil extracted. 
FILTERING THE II ALOW AX-LIN SEED OIL MIXTURE 
The filtering of the halowax-linseed oil mixture is accomplished 
by the use of a small, dry, folded filter, instead of the absorbent- 
cotton filter recommended by Wesson. By using the small folded 
filter, a cleaner filtrate is obtained and with less effort than when 
using absorbent-cotton filter. Only a few drops of the filtrate are 
necessary for making the refractometer reading. 
CLEANING PRISM 
'Warning. — Because of the highly solvent action of halowax oil, it 
is absolutely essential for accurate results that this material be com- 
pletely removed from the faces of the prism after each test has been 
completed. Failure to do this will not only result in an incorrect oil 
test reading, but will also eventually result in a corrosive action on 
the back of the prism. 
TIME REQUIRED FOR TEST 
After the method was developed tests were made to determine 
the amount of time necessary for one man to complete a single 
determination, with the following results: * 
Minutes 
Preparing - snmple (25 grams) 5 
Weighing and adding halowax_! 1 
Grinding 2 
Filtering 1% 
Taking mixture and applying to prism y 2 
Reading and recording result and wiping prism 2 
Total time 12 
