4l4 WHALE-FlSTIEPtY. 



and inferior oils, Vv^liich are discoloured, and more 

 impure, by the denominations of brown oil, and 

 black oil or bilge oil. Brown oil is produced in the 

 way described in the process of boiling ; black or 

 bilge oil is that which leaks out of the casks in the 

 course of the voyage, or runs out of any blubber 

 which may happen to be in bulk, and accumulates 

 in the bottom of the ship. This oil is always very 

 dark coloured, viscous, and possessed of little trans- 

 parency. In the hold of the ship, it imbibes va- 

 rious impurities ; and when strongly acted upon 

 by the hydrogenous gases of the bilge-water, is 

 sometimes so changed in its qualities, that it com- 

 bines to a certain extent with the salt-water on 

 which it floats, and is rendered totally useless. 

 When, however, its oleaginous properties continue 

 unchanged, it is preserved and sold for inferior uses, 

 at a proportionate reduction of price. 



From what has been advanced, we see why the 

 palest oil is esteemed the most valuable. Pale 

 limpid oil has a chance to be the most pure, be- 

 cause any inferior oil mixed with it, or much animal 

 matter combined with it, always has a tendency to 

 heighten the colour and render it viscous. 



As oil kept in open vessels, we are informed, be- 

 comes gradually more and more oxygenated, and 

 also less fluid, it is necessary to keep v/hale-oil 

 closely barrelled up. Another precaution for pre- 



