162 Beport of the Consulting and Acting Con9vltin<j 
guarantee of the purity of the linseed-cakes they offer for sale, and 
also the prevalent disregard by Members of the advice which the 
Society gives them, only to buy cake •which is " guaranteed pure and 
deUvered in good condition." In the spring of 1890, the Council 
issued to the Members of the Society a form of contract embodying 
these conditions, and it is gratifying to know that in the majority 
of cases where this guarantee has been insisted upon, a pure cake 
has been supplied. 
The plea constantly put forward by vendors is, that it is impos- 
sible to guarantee a cake to be "pure,"" and this is given as an 
excuse for a guarantee in such terms as "made from linseed 
imported on a basis of 96 per cent, purity." Such a guarantee is, 
however, useless ; that linseed is bought on a 96 per cent, basis un- 
fortunately does not mean that it contains 96 per cent, of linseed. 
When a cargo of linseed is imported into this country, samples are 
taken and analysed by the Linseed Association, under a contract 
according to which, in the case of Calcutta seed, 4 per cent, of admix- 
ture is allowed. The amount of dirt and foreign seed is determined 
in a sample drawn from the cargo, and, should it exceed the allowed 
4 per cent., a reduction is made in the price. Xon-oleagiaous seeds 
and dirt are considered valueless, but oleaginous seeds, other than 
linseed, are reckoned as being half the ^•alue of Unseed. A cargo of 
linseed may thus be bought on the 96 per cent, basis, and yet not 
contain anything like 96 per cent, of linseed. In the quarterly 
report of the Chemical Committee for IMarch 1890, a case is men- 
tioned in wliich the manufacturers of a Unseed-cake, which was re- 
ported on as containing an excessive quantity of sand, stated that 
they foimd that some of the seed which they had bought on the 96 
per cent, basis containefl no less than 28 per cent, of dirt. 
A guarantee commonly insisted on by cake-makers is that of 
" 95 per cent, pure." This is open to the objection that, after the 
seed has been crushed and made into cake, it is impossible to ascertain 
definitely whether there is 95 per cent, of linseed in it or not. Before 
the seed is crushed it is perfectly easy to determine this ; but,»when 
one is no longer able to pick out the individual seeds, nothing more 
than an approximation to the real percentage can loe arrived at. 
Again, in such a guarantee, no notice is taken of what the 5 per 
cent, of impurity consists ; it might be, for instance, some poison- 
ous seed, such as castor-oil bean or mustarfl. Such a guarantee, 
further, opens the door to the wilful admixture with a pure seed of 
adulterants, the exact amount of which cannot l)e precisely deter- 
mined. To the cake-makers who endeavour by careful screening to 
produce a really pure cake, the recognition of such a guarantee as 
the above is an injustice. 
That linseed-cake, in order to be considered pure, should be abso- 
lutely free fn>in every particle that is not linseed is of course 
impracticable. Linseed naturally contains impurities, and it is 
hardly possible to remove every trace of these. By careful screen- 
ing, however, the purification of the seed can b^ carried to an extent 
which leaves it prjictically pure : and this is, in fact, actually done 
