March 24th.--It is Harmattan season to-day. The thermometer has fallen from 84° to 71° Fahrenheit, but the general rise and fall of the thermometer at Whydah may be calculated to range from 78° to 84° during the month of March; though, as will be seen, sudden and extraordinary changes have taken place in the temperature. Salt is made in great abundance at Whydah, and forms one of their principal articles of trade, and is transported to a great distance into the interior. Their method of procuring the salt is simple and easy. Near Whydah the sea flows into the lagoon at high water, consequently it is very salt. During the ebb-tide the lagoon also ebbs, and the great heat of the sun causes such rapid evaporation, as to leave the salt on the surface, so as to resemble hoar-frost or a slight fall of snow. It is then scraped together, and frequently boiled, which cleanses and whitens it, but the natives generally use it in its original state. April 4th.--The _California_, Captain Hunt, arrived here from Cape Coast and Accra, bringing the melancholy intelligence of the death of Dr. M’Hardy, colonial surgeon of Cape Coast. He was a young man of amiable and gentlemanly manners, and shewed great skill in the treatment of the fever prevalent in that country. It is rather singular that this gentleman should never have experienced an hour’s sickness during the two years he resided in Africa, till the short illness which had proved fatal to him. He had been relieved from his station by Dr. Lilley, and was only waiting for a passage to England. Dr. M’Hardy attended me with great kindness and attention during the fever which attacked me. He was one of the officers of the garrison whose kind and generous treatment I shall ever remember with the warmest feelings of gratitude. Indeed I have experienced great kindness from every European on this coast, as well as from the respectable body of civilized Africans.