Some witnesses have argued, that this question of degree need not be defined but may be left to be solved by the practical sense of a jury. By what jury? In England or at Sierra Leone? Under what uncertainties and obstructions would the most scrupulous trader deal with the Coast of Africa, if, for the misinterpretation of such instructions, as the nature of such a case will admit, by a supercargo, his vessel and goods are liable to be brought some hundreds or thousands of miles out of their course, to have the question decided by a jury, whether some person or some factory dealt with was _principally_ or not engaged in the Slave Trade, it being unlawful if _principally_, lawful if _partially_, in some unknown and varying proportion, so engaged. The question for the Legislature to consider is, whether it is worth while to do all this, to infuse so much risk and uncertainty into a trade which it wishes to encourage, which it looks to as one of the main instruments for the civilisation of Africa, for the sake of interfering with so small a proportion of the facilities which commerce, permitted at all with Africa, under her present circumstances, must of necessity afford more or less to the Trade in Slaves. For unless all other countries can be persuaded to take the same view, it must indeed be a small proportion, and little indeed will have been done towards the object; an obstruction will merely have been raised for such length of time as may be required for conveying the same goods from England or from foreign countries through other channels. It would be merely a transfer, and a transfer to parties less friendly to the object, and less under control. We have had ample evidence, that foreign vessels already carry on this trade to a considerable extent; nor is there any right by existing treaty with foreign nations, nor can it be expected, that we should obtain it, to interrupt foreign vessels engaged in such a traffic. But indeed, how would it be carried out? The right of search, in any shape, is one, as we know by experience, that requires the greatest delicacy in carrying out with the ships of friendly nations. But what kind of search must that be, which would seek to ascertain, on board of an apparently innocent vessel, innocent in her build and in her equipment, and freighted with innocent goods, whether the destination of such goods was not made unlawful by some document hidden in the most obscure recesses of the vessel? How prolonged, how minute, consequently how irritating at all times, how vexatious, if unsuccessful; how likely to be unsuccessful, if not guided by more obvious indications; how likely consequently to lead to disputes and collisions among nations, most injurious, if not fatal to that harmonious co-operation for the common object which is so absolutely essential to success. It must not be lost sight of how large a share