An error, very general through Europe and one which influences opinion respecting the effects of the abolition of the slave-trade, is that in those West India islands called sugar colonies, the majority of the slaves are supposed to be employed in the production of sugar. The cultivation of the sugar-cane is no doubt a powerful incentive to the activity of the slave trade; but a very simple calculation suffices to prove that the total mass of slaves contained in the West Indies is nearly three times greater than the number employed in the production of sugar. I showed seven years ago that, if the 200,000 cases of sugar exported from the island of Cuba in 1812 were produced in the great establishments, less than 30,000 slaves would have sufficed for that kind of labour. It ought to be borne in mind for the interests of humanity that the evils of slavery weigh on a much greater number of individuals than agricultural labours require, even admitting, which I am very far from doing, that sugar, coffee, indigo and cotton can be cultivated only by slaves. At the island of Cuba it is generally supposed that one hundred and fifty negroes are required to produce 1000 cases (184,000 kilogrammes) of refined sugar; or, in round numbers, a little more than 1200 kilogrammes, by the labour of each adult slave. The production of 440,000 cases would consequently require only 66,000 slaves. If we add 36,000 to that number for the cultivation of coffee and tobacco in the island of Cuba, we find that about 100,000 of the 260,000 slaves now there would suffice for the three great branches of colonial industry on which the activity of commerce depends. COFFEE. The cultivation of coffee takes its date, like the improved construction of cauldrons in the sugar houses, from the arrival of the emigrants of San Domingo, especially after the years 1796 and 1798. A hectare yields 860 kilogrammes, the produce of 3500 plants. The province of the Havannah reckoned: In 1800 60 cafetales. In 1817 779 cafetales. The coffee tree being a shrub that yields a good harvest only in the fourth year, the exportation of coffee from the port of the Havannah was, in 1804, only 50,000 arrobas. It rose: In 1809 to 320,000 arrobas. In 1815 to 918,263 arrobas. In 1815, when the price of coffee was fifteen piastres the quintal, the value of the exportation from the Havannah exceeded the sum of 3,443,000 piastres. In 1823, the exportation from the port of Matanzas was 84,440 arrobas; so that it seems not doubtful that, in years of medium fertility, the total exportation of the island, lawful and contraband, is more than fourteen millions of kilogrammes.