These measures have also prepared the way for the establishment of Christian missions, as well as permitted to legitimate traffic its full development. Missions and the slave-trade have an inverse ratio between them as to their progress. When the one dwindles, the other grows. Although it was no ostensible purpose of the squadron to forward missions, yet the presence of cruisers has been essential to their establishment and success. Trade of all kinds was originally an adjunct to the slave-trade. Cargoes were to be sold where they could find a purchaser. Gold, ivory, dye-stuffs and pepper were the articles procured on the coast. All of these are from exhaustible sources. The great vegetable productions of the country, constituting heavy cargoes, have but lately come into the course of commerce. Hunting and roaming about supplied the former articles of commerce. The heavier articles now in demand require more industry with the hands, and a settled life. Trade thus becomes inconsistent with slavery, and hostile to it; and the more so as it becomes more dependent on the collection of oil, ground-nuts, and other products of agriculture. Covering the coast now with trading establishments, excludes the slaver. The efforts of the squadrons were necessary to carry out this proceeding, for commerce needed to be protected against the piracies of the slaver afloat and the ravages of the slaver on shore. Exposure to capture gave origin to the barracoons. A slaver could no longer leisurely dispose of her cargo, at different points, in return for slaves who happened to be there. The crime now required concealment and rapidity. Wholesale dealers on shore had to collect victims sufficient for a cargo to be taken on board at a moment’s notice. This required that the slaver should arrive at the station, with arrangements previously made with the slave-factor, ready to “take in;” or that she should bring over a cargo of goods in payment for the slaves. In the case of falling in with British cruisers, an American slaver was inviolate, on presenting her register, or sea-letter, as a proof of nationality, and could not be searched or detained. But the risk of falling in with American cruisers, especially if co-operating with the British, led to the disguise of legal trading; with a cargo corresponding to the manifest, and all the ship’s papers in form. An instance of this occurred, as will be seen, in the capture of the second slaver by the “Perry.”