OILS 453 



so produced was much better in quality than the best prepared by the old process, and 

 free from the unpleasant smell common to all seal oil. His subsequent experiments 

 resulted in the invention of a steam apparatus for rendering seal and other oils, 

 which has been found to answer an admirable purpose, and for which he received 

 letters-patent under the Great Seal of the Island of Newfoundland. 



The advantage of this process must be manifest, when it is understood that twelve 

 hours suffice to render the oil, which by the old process requires about six months ; 

 that a uniform quality of oil is produced superior to the best pale by the old process, 

 and free from smell ; that a considerable percentage is saved in the yield, and what 

 is termed pah seal, produced from the old as well as from the young seal. Besides, 

 if this process were universally adopted, the manufacturing season would cease by the 

 31st of May, and the community would be saved from the annoyance attending the 

 old process. 



Porpoise Oil. This oil very much resembles whale oil. 



Cod-liver Oil. This oil is obtained principally from the livers of the common cod 

 (Callarias; Gadus Mnrrhua), previously called Asellus major, and also from some 

 allied species, as the Dorse (Gadus caUarias), the Coal Fish (Merlangus carbonarius), 

 the Burbot (Lota vulgaris), the Ling (Lota inolva), and the Torsk (Brosiimis vulgaris], 

 The mode of preparing this oil varies in different countries; that found in the 

 London market is the produce of Newfoundland, where, according to Pennant, it 

 is thus procured : Some spruce boughs are pressed hard down into a half tub, having 

 a hole through the bottom ; upon these the livers are placed, and the whole exposed 

 to the sun. As the livers become decomposed the oil runs from them, and is caught 

 in a vessel placed under the tub. 



De Jongh describes three kinds of cod-liver oil : the pale, pale brown, and brown. 



Pale cod-liver Oil. This is golden-yellow ; without disagreeable odour ; not bitter, 

 but leaves a peculiar acrid, fishy taste in the mouth ; has a slight acid reaction ; 

 sp. gr. 0-923 at 63'5 Fahr. Cold alcohol dissolves from 2'5 to 27 per cent, of the oil; 

 hot alcohol from 3'5 to 4'5 per cent. It is soluble in ether in all proportions. 



Pale brown cod-liver Oil. Colour of Malaga wine ; odour not disagreeable ; bitterish, 

 leaving an acrid, fishy taste in the throat ; reacts feebly as an acid ; sp. gr. 0'924 at 

 63'5 Fahr. A little more soluble in alcohol than the pale oil. 



Dark brown cod-liver Oil. This is dark brown, and by transmitted light is greenish ; 

 it possesses a disagreeable odour, and a bitter and empyreumatic taste, which remains 

 some time in the fauces ; it is slightly acid ; sp. gr. 0'929 at 63'5 Fahr. Still more 

 soluble in alcohol than the pale brown oil. 



Cod-liver oil is principally used in medicine ; for a fuller description of it, see 

 Pereira's Materia Medica. 



Dugong Oil. This oil has been used instead of cod-liver oil, principally in Australia; 

 but as very little, if any, real Dugong oil has reached England, it will merely require 

 a short notice here. The Dugong is an herbivorous animal, belonging to the order of 

 Sirenia, and is found on the northern coast of Australia, in the Eed Sea, the Persian 

 Gulf, and also in the Indian seas. It has received different names by different 

 nations. In the Indian seas it is sometimes found of a large size, from 18 to 20 feet 

 long; but in Australia it is seldom caught of more than 12 or 14 feet. In its general 

 form it resembles the common whale. Its favourite haunts are the mouths of rivers 

 and straits between proximate islands, where the depth of water is but trifling (3 or 

 4 fathoms), and where, at the bottom, grows a luxuriant pasturage of submarine algae 

 and fuci, on which it feeds. The oil is obtained by skinning the animal and then 

 boiling down the 'speck.' It was used by the natives of Australia originally for 

 burning. 



Adulteration of the Oils. Owing to the large quantities of oil of various kinds 

 which are now used, and their difference in price, many are the adulterations which 

 take place. Thus the best olive oil for the table is mixed with oils of less value, as 

 poppy oil, sesame oil, or ground-nut oil ; and the second olive oil, for the manufactures, 

 with colza oil ; and again colza oil itself mixed with poppy, camelina, and linseed 

 oils, but more frequently with whale oil, &c. Various means have been proposed to 

 discover these admixtures. M. Lefebvre proposed to take advantage of the difference 

 of density of the several oils, but this is a very insufficient test, as many of the oils 

 have nearly the same density. 



M. Poutet treats the oil to be tested with one-twelfth of its weight of a solution of 

 nitrate of mercury, containing hyponitric acid ; this latter substance converts the 

 oleine of most of the non-drying oils into a solid substance, elaidine. By this means 

 pure olive oil will become perfectly solid after an hour or two, whereas poppy oil 

 and the drying oils in general remain perfectly liquid ; it would therefore result that 

 olive oil adulterated with those latter oils would be prevented from solidifying more 

 or less, according to the quantity of these oils present. An improvement in this process 



