The oil is peculiarly valuable for the formation of ointments, from its capability of being kept for almost any length of time without entering into combination with oxygen.  This property, together with the total absence of color, smell, and taste, peculiarly adapts it to the purposes of the perfumer, who is able to make it the medium for arresting the flight of those highly volatile particles of essential oil, which constitute the aroma of many of the most odoriferous flowers, and cannot be obtained by any other means, in a concentrated and permanent form.  To effect this, the petals of the flowers, whose odor it is desired to obtain, are thinly spread over flakes of cotton wool saturated with this oil, and the whole enclosed in air tight tin cases, where they are suffered to remain till they begin to wither, when they are replaced by fresh ones, and the process thus continued till the oil has absorbed as much as was desired of the aroma; it is then separated from the wool by pressure, and preserved under the name of essence, in well stopped bottles.

By digesting the oil thus impregnated in alcohol, which does not take up the fixed oil, a solution of the aroma is effected in the spirit, and many odoriferous tinctures or waters, as they are somewhat inaccurately termed, prepared.  By this process most delicious perfumes might be obtained from the flowers of the Acacia tortuosa, Pancratium carribeum, Plumeria alba, Plumeria rubra, and innumerable other flowers, of the most exquisite fragrance, which abound within the tropics, blooming unregarded, and wasting their odors on the barren air.”

THE OIL PALM.

There are several species of this genus of beautiful palms of the tribe Cococinae, but that chiefly turned to account is Elais guineensis, a native of the Coast of Guinea to the south of Fernando Po, which furnishes the best oil.

There are three other varieties—­E. melanococca, a native of New Granada, E.  Pernambucana, common on the coast of Brazil, and J. occidentalis, indigenous to Jamaica.  All the species grow well in a sandy loam and may be increased by suckers.

The value of the oil of this palm, as an article of commerce, is exemplified by the large annual imports, averaging more than 516,000 cwt. for many years past.

Our supplies of palm oil are almost wholly derived from the West Coast of Africa, of which it is the staple article of export.

Palm oil has the greatest specific gravity of any of the fixed vegetable oils.  It is used principally in this country for making yellow soap.  But the inhabitants of the Guinea coast employ it for the same purposes that we do butter.

The trade in palm oil has almost driven out the slave trade from the Bight of Benin, which was a few years ago one of its principal seats.  The old slave traders at Whydah have generally gone into the palm oil trade, and are carrying it on to a very great extent.  In August 1849, no less than twelve vessels were lying at that port taking in oil; whilst, only three years before, it was rare to see three vessels there at once, and of those in all probability two would be slavers.