300 Annual Report for 1887 of the Consulting Chemist. 
cakes ; indeed, the chief feature of the analytical work of the year 
has been that performed in connection with linseed-cakes, their 
adulterants, and the methods of detecting and estimating the 
same. It is hardly too much to say that the practice of mixing 
foreign seeds and other materials with linseed, previous to 
pressing it into cake, reached its climax in 1887. The Royal 
Agricultural Society has for a long time contended for the purity 
of feeding materials, and the increase of adulteration has led to 
renewed activity on its part, as is evidenced by the Quarterly 
Reports of the Chemical Committee in the present number of 
the ' Journal.' 
During the year I took an opportunity kindly offered me of 
inquiring personally into the manufacture of linseed-cakes more 
or less impure. One of the chief points that forcibly impressed 
itself upon me was the impossibility of judging from the figures 
of analysis alone whether a linseed-cake were a pure one or not, 
and the necessity of a special microscopical examination in all 
doubtful cases. This is a practice which I am glad to find has 
since been taken up by other chemists, as the necessity has 
become more and more apparent. Of the materials used to 
adulterate linseed-cakes, the one now most frequently occurring 
is rajje refuse, or rape seed from which the oil has been extracted 
by chemical means. The following table gives analyses of linseed- 
cake made from pure seed, and of other cakes made from the 
same seed after admixture with different pei'centages of the 
aforesaid rape refuse : — 
Pure 
Unseed 
cake 
Linseed 
cake with 
5 % rape 
refuse 
Linseed 
cake with 
10 % rape 
refuse 
Linseed 
cake with 
30 % rape 
refuse 
10-29 
12-28 
10-97 
11-32 
Oil 
12-66 
11-33 
10-53 
1060 
Albuminous ccmpountls (flcsh-form- 
28-59 
29-57 
28-93 
30-87 
Mucilage, digestible fibre, kc. . . . 
34-85 
32-37 
35-19 
31-07 
8-07 
8-81 
8-80 
10-16 
5-54 
5-64 
5-58 
5-98 
100-00 
100-00 
100-00 
100-00 
' Containing nitrogen .... 
4-57 
-59 
4-73 
-80 
4-62 
•59 
4-94 
1-09 
Taking these figures, there is not one single constituent 
that could be pointed out as indicating the least suspicion of the 
cake being impure. The sand is not high in any of them, nor 
the woody fibre exceptional. In the mixtures containing 5 and 
10 per cent, respectively, there is but little more of either than 
