_Castor Oil Rhinum_.-The bush which produces the bud from which this oil and valuable medicine is extracted, grows in great exuberance upon the Windward Coast, and its vicinity. A species of bark is in great abundance also, and is said to be equal in virtue to the Peruvian. The foregoing enumeration of natural productions, is the result of unscientific enquiry only; but unquestionably, industrious and professional research, would discover infinitely more to philosophic and commercial contemplation, and develope the arcana of nature, dormant here through ignorance and barbarism. On the 10th of May, I set out from Bance Island, with the view of exploring the two branches of the Sierra Leone river, the Rochelle, and the Port Logo. After rowing a few hours I arrived at the factory of Miffaré, formerly occupied by a Mr. Berauld, a Frenchman, but now attached to Bance Island. Mr. Hodgkin, with his people, then in possession of the factory, accompanied me up the Port Logo branch the following morning, taking a number of towns in our way, and visiting the chiefs. The course of this branch of the river is extremely serpentine, and is navigable for light vessels to a little way from the town of Port Logo which is now the residence of Alimami, a Mandingo chief, who assumes the title of emperor. The banks are overgrown with the mangrove tree, interwoven together, so as to form an almost impenetrable thicket, excluding the air, which, with the extreme heat of the sun, and the noxious insects which are extracted by its rays from the swamps and woods, renders this navigation intolerably oppressive. The chief part of its trade is in slaves, camwood, and ivory, the latter, however, being small, although Port Logo commands a very extensive back country. When we came near the town of Port Logo, which is extremely difficult of approach at low water, we announced our visit by saluting in the manner of this country, which is what they call bush firing, or in other words is a continued irregular firing of musquetry. It was soon discovered who we were, and crowds of natives flocked down from the upper town, which is situated on the declivity of a hill, to give us service, or to pay their respects. Our first visit was to _Marriba_, one of Alimami's head men, and a resident of what they consider the lower town.