8.--It has been raining for three days, almost incessantly. No Macedonian yet. 10.--Dined on shore. Our captain and five officers, the master and surgeon of an English merchantman, and the captain of the French schooner, were of the party. It was a pleasant dinner. The conversation turned principally upon the trade and customs of the coast. The slave-trade was freely discussed; and the subject had a peculiar interest, under the circumstances, because this identical Frenchman, at table with us, is suspected to have some connection with it. It is merely a surmise. The French captain speaks a little English; but, after dinner, as a matter of courtesy, we all adopted his native language. Our friend Colonel Hicks, as usual, did most of the talking; he is as shrewd, agreeable, and instructive a companion, as may often be met with in any society. The dinner-conversation, above alluded to, suggests some remarks in reference to the slave-trade. There is great discrepancy in the various estimates as to the number of slaves annually exported from Africa. Some authorities rate it as high as half a million. Captain Bosanquet, R.N., estimates that fifteen thousand are annually sent to the West Indies, and a greater number to Arabia, all of which are from Portuguese settlements. He affirms that the trade has increased very much between the years 1832 and 1839, and particularly in the latter part of that period; an effect naturally consequent upon the great number of captures made by the English cruisers. A trader, for instance, contracting to introduce a given number of slaves into Cuba, must purchase more on the coast to make up for those lost by capture. Captain Brodhead, another British officer, says that the number of slaves carried off is grossly exaggerated, and that the English papers told of thousands being shipped from a port, where he lay at anchor during the period indicated, and for fifty days before and afterwards; in all which time, not a slave vessel came in sight. Doctor Madden states, that, during his residence in Cuba, the number of slaves annually imported was twenty-five thousand. Sir Thomas Fowell Buxton calls it one hundred and fifteen thousand! Her Majesty's Commissioners say that the number is as well known as any other statistical point, and that it does not exceed fifteen thousand. The slave-trade rose to a great height in 1836, owing principally to the high price of colonial produce. I was in Cuba in that year, and witnessed the great activity that prevailed in buying negroes, and forming plantations, especially those of sugar. The prices have since fallen, and the slave-trade decreased, on the plain principle of political economy, that the demand regulates the supply.