"The principal product of the Olive is oil, but the pickled fruit is also a valuable article of commerce.
The simplest manner of preserving the green olives is by covering them with a solution of common salt impregnated with fennel, cumin, coriander-seed and rose wood : the most perfect method is that employed for the picholines of Provence, [France] which are so called from Picciolini, by whom the process was invented.
They are gathered in the beginning of October, and the finest of them are selected and thrown into a weak solution of soda or potash rendered caustic with lime. In this solution they remain eight or ten hours till the pulp ceases to adhere to the stone; they are then steeped, during a week, in pure, cold water, daily renewed, and are afterwards transferred to an aromatic brine.
Such of them as are destined for the tables of the luxurious are taken out after a certain time, deprived of the stone, in place of which is substituted a caper or a bit of truffle , and closed up in bottles of the finest oil. In this manner they are kept palatable for two or three years.
The sweet olive of the ancients, which was eaten without preparation , is said to exist in the kingdom of Naples."Hillhouse, Augustus Lucas. Description of the European Olive Tree. [Paris:] 1818. Also the above picture.
Pickled Olives 1749
"When they, come to us in Pickle or Brine they are generally of a greenish Colour, but if suffered to hang upon the Tree till quite ripe, they become black, and very hot in the Mouth. … Pickled Olives, being eaten before Meals, says Schroder, provoke an Appetite, raise and comfort a moist Stomach, and move the Belly. But I have here inserted this Fruit on account of its Oil, expressed from it when ripe; which is not only used in Salads and other Dishes at Table, but is of great Service in many Purposes of Physick."A Treatise on Foreign Vegetables ... by Ralph Thicknesse, M.D. London: 1749