FIXED OILS. 231 



cess : " A press lies down on the ground ; it con- 

 sists of two blocks, between which the seed is put 

 and crushed, and the oil expressed. One of the blocks 

 composing- the press is fixed and immoveable ; and 

 against this the other is forced by means of graduated 

 wooden wedges, which, increasing in size at the fore- 

 most end, are driven in with a very long wooden 

 club. At the side is an opening to let out the oil, 

 which is received in a vessel placed underneath." 



We might enumerate several other vegetable sub- 

 stances, affording oils of different qualities, but we 

 have described the more important ; the rest, for the 

 most part, are scarcely known beyond the countries 

 of their production, and have no place in commerce. 

 Their existence is only interesting inasmuch as it 

 shows the infinite variety of natural productions, from 

 which, in spite of their dissimilarity, the ingenuity of 

 man can produce the same, or nearly the same, bene- 

 ficial results. 



