450 OILS 



of the Atropa belladonna, and is there used for lighting and cooking. It is limpid, of 

 a golden-yellow colour, insipid taste, and no odour. 



Oil of Tobacco-seeds. The seeds of the Nicotiana tabacum yield about 31 per cent, 

 of their weight of a drying oil, which is limpid, of a greenish-yellow colour, and no 

 odour. It does not possess any of the narcotic principles of the plant. 



Cotton-seed OH. Many attempts have been made to render fit for use the oil 

 obtained from the seeds of the cotton-plant (Gossypium Barbadcnse, &c.), as immense 

 quantities of these seeds are allowed to rot, or used only as manure upon the cotton- 

 lands of the south of the United States of America. When obtained by expression, 

 the oil which runs from the press is of a very dark red colour. It, however, deposits 

 some of the colouring- matter by standing, as well as a portion of semi-fluid fat ; and 

 in cold weather this is precipitated in large quantities ; and only partially redissolves 

 again by increase of temperature. The great obstacle to the use of the oil thus 

 obtained is its colour, which appears to bo derived from a dark, resinous substance, 

 presenting itself in small dots throughout the seed. These may readily be seen by 

 examining a section of the seeds with a lens, or even with the naked eye (Mr. Wayne, 

 Pharmaceutical Journal, xvi. 335). In bleaching the oil loses from 10 to 15 per cent., 

 a portion of which may be again recovered and used for making soap, for which pur- 

 pose cotton-seed oil seems best fitted. It is a drying oil, and consequently not well 

 fitted for machinery ; and, when burnt, rapidly clogs the wick. A very good soap for 

 common purposes is made from it in New Orleans. 



Mr. Wayne also states, ' that the oil, to be made profitably, should either bo 

 manufactured in the vicinity of the cotton-plantation, as the seeds, from the attached 

 fibre, are bulky, and the cost of transportation great ; or the seed shoiild be hulled 

 at the spot, and shipped to the place where it is to be pressed in that condition, as it 

 requires three or four bushels of seed in the wool to produce one bushel of hulled seed 

 ready for the mill. The hull and attached fibre are useful for paper stock ; and the 

 cake, left after the extraction of the oil, is nearly as valuable a food for cattle as that 

 of linseed. 



' It appears that boiling the crushed seeds with "water yields a very bland, light 

 coloured oil. 



' The desire to bring this oil into use still exists, for a sample of it was sent a few 

 months since from a merchant in America to a friend of mine to see if he could suc- 

 ceed in purifying it, which no doubt will ultimately be effected by some one." 



Croton Oil. This oil is obtained from the seeds of the Croton Tiglium by expres- 

 sion, or by the use of alcohol. It is a most violent purgative, and its only use is in 

 medicine. See Pereira's Materia Medica. 



ANIMAL OILS. 



The only oils which will be mentioned here are lard oil, tallow oil, and neat's-foot 

 oil. The solid fats will be described under their different heads. See STEARINE. 



Lard Oil. This oil is now imported largely from America ; and is obtained by 

 subjecting ordinary hog's-lard to pressure, when the liquid part separates, while 

 the lard itself becomes much harder. It is employed for greasing wool, for which 

 purpose it answers very well, and may be obtained at a low price. According 

 to Braconnet, lard yields 0'62 of its weight of this oil, which is nearly colourless. 

 Specific gravity 0'915 (Chevreul). 100 parts of boiling alcohol dissolve 123 parts 

 of it. 



Tallow Oil. This oil is obtained from tallow by pressure. The tallow is melted, 

 and, when separated from the ordinary impurities by subsidence, is poured into 

 vessels, and allowed to cool slowly to about 80, when the stearine separates in 

 granules, which may be separated from the liquid part by straining through flannel, 

 and is then pressed, when it yields a fresh portion of liquid oil. It is employed in 

 the manufacture of some of the best soaps. 



Neat's-foot Oil. After the hair and hoofs have been removed from the feet of 

 oxen, they yield, when boiled with water, a peculiar fatty matter, which is known 

 under the name of neafs-foot oil ; after standing, it deposits some solid fat, which is 

 separated by filtration : the oil then does not congeal at 32, and is not liable to 

 become rancid. It is often mixed with other oils. This oil is used for various pur- 

 poses, especially, owing to its remaining liquid at so low a temperature, for oiling 

 church clocks, which require, in consequence of the cold they are exposed to, an oil 

 which is not liable to solidify. 



Fisu OILS. 



Although the whale is not, truly speaking, a fish, the oil obtained from it is classed 

 among the fish oils ; and those which will be described here are, whale oil, porpoise 



