In 1839 the corrective was more stringently applied. Permission had then, or soon after, been wrung from different slave-trading powers, to capture vessels outward-bound for Africa, when fitted for the slave-trade, as well as after they had taken in their cargoes. The treaties provided that vessels equipped for the traffic might be captured, so as to prevent the crime. A slaver was thus to be taken, because she was a slaver; just as it is better to shoot the wolf before he has killed the sheep than afterwards. If a vessel, therefore, was found on the African coast with slave-irons, water in sufficient quantity for a slave-cargo, with a slave-deck laid for packing slaves--somewhat as the carcases of sheep and pigs in a railway train, with the exception of the fresh air--she was seized and condemned before committing the overt act. Under this arrangement, with a rigorous squadron, double the number of captures were made, during the next ten years, as compared with the previous twenty. Seeing, then, that, as before noticed, one thousand and seventy slave-vessels were captured, and of the slaves who were not dead, a great proportion were landed at Sierra Leone, and that the whole population of that colony, although established for nearly sixty years, does not amount to more than forty-five thousand souls, young and old, it may be conceived what a fearful waste of life has arisen even from deliverance. The efforts of this squadron were conjoined with those of France and the United States. The former had withdrawn from the treaty stipulating the right of search, and sent a squadron of her own to prevent French vessels from engaging in the slave-trade; and the United States, which never has surrendered, and never will surrender, the inviolability of her own flag to a foreign power, guaranteed, in 1842, to keep a squadron on the coast. These, together with other subsidiary means, had reduced the export of slaves in 1849 to about thirty-seven thousand, from one hundred and five thousand. And since that period the trade has lessened, until in Brazil, the greater slave-mart, it has become almost extinct; although at times it has been earned on briskly with the island of Cuba. The subsidiary means alluded to arose out of the presence of the squadrons, and would have had no effect without them. They consist in arrangements, on the part of England, with some of the native powers, to join in checking the evil, and substitute legal trade, and in the conversion of the old slave-factories and forts into positions defensive against their former purpose.