"Provence oil, the produce of Aix, is the most esteemed. Florence oil is the virgin oil expressed from the ripe fruit soon after being gathered; it is imported in flasks surrounded by a kind of network formed by the leaves of a monocotyledonous plant, and packed in half chests; it is that used at table under the name of salad oil. Lucca oil is imported in jars holding nineteen gallons each. Genoa oil is another fine kind. Galipoli oil forms the largest portion of the olive oil brought to England, it is imported in casks. Apulia and Calabria are the provinces of Naples most celebrated for its production; the Apulian is the best. Sicily oil is of inferior quality; it is principally produced at Milazzo. Spanish oil is the worst. The foot deposited by olive oil is used for oiling machinery, under the name of' droppings of sweet oil.'"—("Pereira's Materia Medica.")
The manufacture of olive oil in Spain has undergone very considerable improvement during the last few years; in particular, the process for expressing the oil has been rendered more rapid and effectual by the introduction of the hydraulic press, and thus the injurious consequences which resulted from the partial fermentation of the fruit are avoided.
There are four different kinds of oil known in the districts where it is prepared.
1. Virgin oil—A term which is applied, in the district Montpellier, to that which spontaneously separates from the paste of crushed olives. This oil is not met with in commerce, being all used by the inhabitants, either as an emollient remedy, or for oiling the works of watches. A good deal of virgin oil is, however, obtained from Aix.
2. Ordinary oil.—This oil is prepared by pressing the olives, previously crushed and mixed with boiling water. By this second expression, in which more pressure is applied than in the previous one, an oil is obtained, somewhat inferior in quality to the virgin oil.
3. Oil of the infernal regions.—The water which has been employed in the preceding operation is in some districts conducted into large reservoirs called the infernal regions, where it is left for many days. During this period, any oil that might have remained mixed with the water separates and collects on the surface. This oil being very inferior in quality, is only fit for burning in lamps, and is generally locally used.
4. Fermented oil is obtained in the departments of Aix and Montpellier, by leaving the fresh olives in heaps for some time, and pouring boiling water over them before pressing the oil. But this method is very seldom put in practice, for the olives during this fermentation lose their peculiar flavor, become much heated, and acquire a musty taste, which is communicated to the oil.
The fruity flavor of the oil depends upon the quality of the olives from which it is pressed, and not upon the method adopted in its preparation,"—(French "Journal de Pharmacie.")
The price of olive oil is sufficiently high to lead to its admixture with cheaper oils. The oil of poppy seeds is that which is usually employed for its adulteration, as it has the advantage of being cheap, of having a sweet taste, and very little smell. M. Gobley has invented an instrument which he calls an areometer, to detect this fraud. It is founded on the difference between the densities of olive oil and oil of poppies.
The imports, which in 1826 were only 742,719 gallons, had risen in 1850 to 5,237,816 gallons. The following figures show the progressive imports and consumption:—