1072. Prolongation of fruits. When fruits nearly, but not quite ripe, are placed in an atmosphere free from oxygen, the process of ripening is suspended; but it may be reestablished within certain limits of time, by replacing them in the common atmosphere. Hence by placing at the bottom of a bottle a paste formed of lime, sulphate of iron, and water, which may deprive the atmospheric air enclosed of its oxygen, and suspending fruit gathered a few days before it is ripe in such a bottle, and afterwards hermetically sealing it by a cork covered with cement, the fruits may be preserved for a longer or shorter time, according to their nature. 'Peaches, plums, and apricots may be preserved from twenty days to a month ; pears and apples for three months : if they are withdrawn after this time, and exposed to the air, they ripen well; but, if the times mentioned are much exceeded, they undergo a particular alteration, and will not ripen well.' (Ibid. vol. ii. p. 258.)
