From the tubs, or “bacs,” the juice was run through a series of kettles, or open-fire caldrons, for concentration. The kettle next in position to the bac into which the juice from the table fell was called _la grande_, because it was really the largest of the set. It was farthest from the fire and served as a defecator. As soon as the juice contained in it became heated, a thick, creamy substance formed on the surface and was immediately skimmed off. The liquor was then ladled into the second kettle, where the boiling became more lively on account of closer proximity to the furnace. The juice bubbled up in foam and at this point the cleansing process began. A long, flat piece of wood was passed slowly over the surface of the liquor, thus removing certain impurities. Here the mixture of lime begun in _la grande_ was continued until the liquor was found to be perfectly clear. Passing to the third kettle, the liquor was reduced to syrup by the increased heat. It was concentrated in the fourth and boiled to grain in the fifth. Directly under the fifth and last kettle of the set was the furnace, which was fed by bagasse and cane trash. The boiling process finished, the sugar was removed from kettle number five and placed on tables, where it remained until it had to be taken to larger tables farther on to make room for a fresh batch. There it stood with other boilings until the following morning. Then the crystallized mass was shoveled into pots and carried to large bins constructed so that the liquor, or syrup, could drain off. This usually took from fifteen to twenty days, after which time the sugar was dug out by pick and shovel, put into baskets and taken to be spread out in the sun to dry. After two to three hours of this drying, according to the intensity of the sun’s rays, the sugar was packed in a double sack containing about 135 pounds. By such means little more than one-third of the sugar in the cane could have been recovered, and the product obtained was heavy and dark in color. From 1816 to 1845 a change was gradually made from the clumsy apparatus just described to three-roller vertical mills, and from wind- and water-driven mills to steam power, thus increasing the extraction. No perceptible improvement was effected in field methods during this period. In 1852 a number of vacuum pans and centrifugal machines were in use. Some eight or ten years later the efforts made to combat the diseases of the cane began to bear fruit and the planters of the coast and inland estates started to exchange cane tops. During the period of 1866 to 1875 single crushing was almost universal. A few factories used double crushing with maceration, but the mills were not powerful. Marked progress was made in the chemical treatment of the juice. Shortly afterward the planters began to appreciate the vital importance of chemical control in their factories and scientific principles were applied to the culture of the cane.