490 ON OUR OIL FLASKS. 



very like stearine, only melting at a lower point. Oleine is difficult to 

 get pure. The best way is to freeze olive oil, when the margarine crystal- 

 lises and sinks, and the oleine is left floating at the top, and can he 

 skimmed off. The imjjortance of all these discoveries, and which of the 

 animal fats and vegetable oils have more or less of these compounds, can 

 hardly be over-estimated, when we see their practical results in the 

 beautiful candles which are sold now at half the original cost, and more 

 than twice the light-giving power, of the ancient wax and muttons ; and 

 in the pure and bright burning oils — so pure and colourless that they 

 reveal the secret of straw-coloured gloves, and do not let them pass for 

 white. 



There is scarcely a portion of the animal body that has not fat mixed 

 with it, either in separate masses, or indistinguishably ; as in the bones 

 and fibrous parts of the body to be got at by only certain processes ; but 

 not many plants yield oil. The richest are the cruciferous tribe, in- 

 cluding the seeds of radish, mustard, rocket, Caruelina (gold of pleasure) 

 garden cress, and rape, in the three varieties of Brassica napus et 

 campestris, the common rape ; Brassica prcecox, summer rape ; and 

 Brassica campestris oleifera, or colza. But these are not all good for 

 food or light ; some of them being of the kind called " drying oils," as 

 we shall see presently. The quantity of oils to be got from plants and 

 seeds varies, not only in different species of the same thing, but accord- 

 ing to climate and culture ; still, for broad measurement, it may be said 

 that nuts yield half their weight of oil ; Brassica oleracea campestris, 

 one-third ; the variety called colza, in France, two-fifths ; hempseed, 

 one-fourth ; and linseed from one-fourth to one-fifth. The grasses and 

 pea tribe (Graminece et Leguminosce) rarely give a trace of oil ; only one 

 of the former — the roots of the cyperus grass, which is not a true grass by 

 the way — and two of the latter ; both foreign. One is called the oil of 

 Ben, from the seeds of a plant {Moringa aptera) growing wild in Arabia 

 and Sp-ia but cultivated in the "West Indies, and chiefly used in per- 

 fumery, " to dissolve out the odoriferous principle of the flowers," being 

 absolutely pure, mild to the taste, inodorous, becoming slowly rancid, 

 and free from all acid ; the other is ground-nut oil, from the Arachis 

 hypogcea, a native of America. The properties of ground-nut oil were 

 tested by a kind of accident in Europe. A large cargo of nuts had 

 arrived at Bremen, and found no purchasers in their natural state, as 

 good for luncheon or dessert ; so the importers expressed the oil, and 

 then found market enough. Where the ground-nut grows, that is, in tro- 

 pical climates, the inhabitants eat the seeds raw, whichthen have a slight 

 resemblance to haricot beans, or make them into a kind of paste like 

 chocolate. They are very pleasant when properly roasted, which is rather 

 hard to get done down stairs ; and have the further quality of being 

 wholesome and nutritious. The potato tribe, Solanacem, gives us hen- 

 bane-seed oil, tobacco-seed oil, and oil of deadly nightshade ; while the 

 Rosacea, which term includes the peach, cherry, plum, almond, and the 



