A hydraulic ram then forces the table carrying the cakes against a press-head, and the exuding oil flows down the sides into a tank below.
Long; in the earlier stages of growth it has a pyramidal form, in open glades the lower boughs often touching the ground, but in old age it acquires a wide almost cedar-like top. The light bluish-green foliage is somewhat lax, very dense in young trees; the cones are long and rather curved, with thin smooth scales a little thickened at the apex, and generally more or less covered with exuding white resin; they are about 5 or 6 in.
The crudest method of rendering oils from seeds, still practised in Central Africa, in Indo-China and on some of the South Sea Islands, consists in heaping up oleaginous fruits and allowing them to melt by the heat of the sun, when the exuding oil runs off and is collected.
The oil exuding in the cold dissolves the smallest amount of colouring matter, &c., and hence has suffered least in its quality.
The oranges, lemons, &c., are peeled, and the peel is pressed against a large number of fine needles, the exuding oil being absorbed by sponges.
The cut cells die, and oxidized products are concerned in the change of color, the brown juices exuding and soaking into the cell-walls.