Pure and Mixed Linseed- Cakes. 
5 
Some kinds of linseed, it will be seen from the preceding- 
tabular statement, yield a good deal more oil than others. The 
quantity of albuminous compounds 
in different samples, and to a minor Fig. 1. — Section of Linseed. 
extent that of woody fibre, and of 
ash, is likewise subject to fluctua- 
tions. Speaking generally, Baltic 
linseed, more especially from Mor- 
shanski seed, has a finer skin, is 
smaller, and produces a more nutri- 
tious cake than Bombay linseed. 
Bombay linseed has a lighter colour 
than Black Sea or Baltic linseed, 
and becomes less gelatinous than 
the latter when mixed with water. 
The annexed woodcut represents 
the structure of linseed under a 
quarter-inch power of a compound 
microscope. 
In the next illustrations Petersburg and Bombay linseed are 
represented of their natural size, and magnified to 140 
diameters : — 
A the outer skin or layer. 
B the second l.iyer. 
C the third layer. 
D the fourth layer. 
Fig. 2. — Exterior of Bombay 
Linseed. 
Fig. 
-Exterior of Petersburg 
Linseed. 
Seeds, natural size ; e.xlerior magnified HO diameteis. 
Linseed, as imported, always contains more or less dirt and 
small weed-seeds, which, however, can be readily separated from 
it by screening. The percentage of the impurities in com- 
mercial samples varies extremely ; in some samples it is as low 
as from 3 to 4 per cent. ; in others as high as 50 per cent, and 
more. Some years ago I obtained about a dozen samples of 
linseed from various sources, and determined in each the 
amount of foreign seeds and other impurities, and as the 
