SECTION XVIII 

 FIXED OILS, FATS AND WAXES 



Fixed oils and fats are substances of either vegetable or animal 

 origin, and consist of various organic acids of high molecular weight 

 belonging chiefly to the stearic, oleic, linolic or ricinoleic acid series 

 combined with glyceryl ; they yield by saponification with caustic 

 alkalies the alcohol glycerol (glycerin) , the alkali combining with the 

 organic acids to form soaps. 



Waxes are solid or, occasionally, liquid substances resembling the 

 fats and oils but differing in yielding monatomic alcohols instead of 

 glycerol by saponification, which is readily effected by boiling alcoholic 

 solutions of caustic alkalies, but not by aqueous. 



POPPY OIL 



(Oleum Papaveris) 



Source, &c. The oil expressed from the seeds of Papaver somni- 

 ferum, Linne. (Compare ' Poppy Capsules.') 



Description, &c. Pale to golden-yellow ; specific gravity 0-924 

 to 0-927 ; iodine value about 133 to 143 (or 157 for oil extracted by 

 petroleum spirit) ; dries to a hard varnish. Consists of the glycerides 

 of linolenic, linolic, oleic and palmitic acids. Used by artists. 



EXPRESSED OIL OF MUSTARD 

 (Oleum Sinapis Expressum) 



Source, &C. The oil expressed from the seeds of Brassica sinapioides, 

 Roth, and of Brassica alba, Boissier. (Compare ' Black Mustard Seeds.') 



Description, &c. Brownish-yellow ; specific gravity 0-914 to 0-920 ; 

 congealing point 17 ; iodine value 96 to 110 (black mustard) or 

 92 to 97 (white mustard). Constituents similiar to those of rape oil ; 

 used as a mildly stimulating embrocation ; also for lubricating, burning 

 and soap-making. 



