Three qualities of sugar are distinguished in the island of Cuba, according to the degree of purity attained by refining (grados de purga). In every loaf or reversed cone the upper part yields the white sugar; the middle part the yellow sugar, or quebrado; and the lower part, or point of the cone, the cucurucho. All the sugar of Cuba is consequently refined; a very small quantity is introduced of coarse or muscovado sugar (by corruption, azucar mascabado). The forms being of a different size, the loaves (panes) differ also in weight. They generally weigh an arroba after refining. The refiners (maestros de azucar) endeavour to make every loaf of sugar yield five-ninths of white, three-ninths of quebrado, and one-ninth of cucurucho. The price of white sugar is higher when sold alone than in the sale called surtido, in which three-fifths of white sugar and two-fifths of quebrado are combined in the same lot. In the latter case the difference of the price is generally four reals (reales de plata); in the former, it rises to six or seven reals. The revolution of Saint Domingo, the prohibitions dictated by the Continental System of Napoleon, the enormous consumption of sugar in England and the United States, the progress of cultivation in Cuba, Brazil, Demerara, the Mauritius and Java, have occasioned great fluctuations of price. In an interval of twelve years it was from three to seven reals in 1807, and from twenty-four to twenty-eight reals in 1818, which proves fluctuations in the relation of one to five.