4S8 



Oil the Composition of Linseed Oil- Cake, 



the per-centao^e of sand or earthy matter introduced wore very 

 considerable, the manufacturer would hardly find his account in 

 such adulteration. So much for speculation. Let us now look 

 at the analyses. With the exception of two cases (specimens 

 1 and 2) the proportion of ash never rises above 10 per cent. 

 The exceptions are two French cakes : but even here the in- 

 crease of mineral matter is not due to sand, but to the real ash 

 of some other vegetable substance than linseed. Of the 22 per 

 cent, of mineral matter in these specimens, more than one-half 

 was carbonate of lime, of which very little is found in the ash of 

 cake in general. It was obviously the ash of some woody matter, 

 and so far mig:ht be due to adulteration, but certainly not by 

 sand. The greater number of the ashes are under 8 per cent. — 

 a quantity which will presently be shown to be but Ihtle above 

 the proper proportion, supposing the cake to be made from pure 

 and perfectly clean seed. The following analyses of the ash of 

 four of these cakes, made in this laboratory by Mr. Ward, will 

 help to explain the point under discussion,* 



Table 9, — Composition in 100 paits of the Ash of Linseed Cake : — 



In taking the mean composition of the ash of linseed-cake, the 

 specimen in the third column has been omitted from the high 

 per-centage of sand which it contains. The other specimens 

 afford a mean per-centage of 5-88 of ash, of which 12*12 is sand 



* These per-centages of ash will all be a little above the mark from imperfect burning. 

 Specimens 11, 12, 25, and 26, give the true ash, the charcoal, being weighed in the 

 aiialysis and deducted. Tlie average quantity of sand and charcoal in these ashes was 

 determined upon the mixed ash of 25 specimens, which gave 9*54 jier cent, of char- 

 coal, and 22'32 per cent, of sand : consequently the ash determinations are 10 per cent, 

 too high, except in the 4 specimens just mentioned. 



