THE OIL CONTENT OF FLAXSEED 
27 
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ture, as well as the refractive index of the halowax oil used, at a 
temperature of 25° C, and from these data determine the change in 
the refractive index of the halowax oil per 1 per cent of linseed oil 
present in the mixture. The results will be of the order illustrated 
in Table 18. The constant obtained will depend upon the original 
refractive indices of the halowax oil and the linseed oil used. 
(2) Determine the percentage by weight of linseed oil present in 
halowax oil when 4 cubic centimeters of halowax oil are mixed with 
a 2-gram sample of ground flaxseed. To do this the weight of 4 
cubic centimeters of halowax oil must first be determined. This 
is accomplished by direct weighing of several 4 cubic centimeter 
portions of halowax oil or by determining the specific gravity of 
the halowax oil and by multiplying this value by 4, the volume of 
halowax oil used in the test. 
Fig. 1. — Apparatus for the optical method for determining oil content of flaxseed 
Knowing the exact weight of the 4 cubic centimeters of halowax 
oil and the weight of linseed oil that would be present in flaxseed 
of known composition, the percentage of linseed oil in the halo wax- 
linseed oil mixture when 2 grams of ground flaxseed are used in the 
test is now determined. To illustrate, suppose a sample of flaxseed 
contained 31 per cent of linseed oil. A 2-gram sample would con- 
tain 0.62 gram of oil. If this 0.62 gram of oil was mixed with 4 
cubic centimeters of halowax oil which weighed 4.904 grams, the per- 
centage of linseed oil in halowax oil would be 11.224 per cent. Con- 
versions of this nature are then made over any part of the scale from 
3 to 45 per cent as is illustrated in Table 19 in whole per cents and 
tenths of 1 per cent, depending on how extensive a table is desired. 
As an aid in preparing this step in the conversion table the follow- 
ing formula will prove useful : 
Weight of oil in 2 -gram sample of flaxseed 
Weight of 4 cubic centimeters of halowax oil + 
weight of oil in 2-gram sample of flaxseed 
Percentage of 
= linseed oil in the 
mixture. 
