Count Louis M. J. O. Degrandpre, naval officer and slave trader, was involved in the slave trade during the 1780s, commanding a ship that carried slaves from the west coast of Africa to Mauritius. In 1792 he landed an illegal cargo of slaves infected with smallpox on the island. This may have caused the smallpox epidemic which ravished the island that year and caused the Colonial Assembly of Mauritius to put a price on his head. Returning to England to support the royalist cause in France, he appears to have spent some ten months at the Cape during 1793. During this time he spent 18 days on Robben Island, and travelled northwards as far as the mouth of the Berg River, at St Helena Bay, though it is not clear whether he went by land or sea. He returned to France in 1799, and in 1801 published three books. One was a French translation of John Barrow's* Travels into the interior of southern Africa..., with notes and criticisms. The second was an account of his exploits in the Indian Ocean, an English translation of which appeared in 1803, titled A voyage in the Indian Ocean and to Bengal, undertaken in the years 1789 and 1790; containing an account of the Seychelles Islands and Trincomale.... The third was his Voyage a la cote occidentale d'Afrique, fait dans les annees 1786 et 1787.... The second volume of this work is largely devoted to a description of the Cape. The accompanying maps and illustrations include a plan of the Castle in Cape Town, and a map of the Cape of Good Hope and its surroundings. The map does not contain much detail, while Saldanha Bay is somewhat distorted and shown too far south.
Degrandpre's contribution to geographical knowledge about the Cape lies in his attempts to apply scientific methods to explain aspects of the local topography and weather. He attempted an explanation, based on the scientific theories of his time, of the origin of the winds at the Cape. This was probably partly based on discussions with Colonel R.J. Gordon*, who had just written an unpublished manuscript on the local weather. Degrandpre's was the first such account to appear in print, though it did not contain significant new knowledge. He held the Neptunist belief that the level of the oceans had steadily declined throughout the history of the earth, and discussed Francois Le Vaillant's* idea that the Cape Flats were formerly covered by the sea, and the Cape Peninsula thus a group of islands. He climbed Table Mountain several times, and speculated on its geological structure and that of neighbouring mountains. Though he managed to correct some of the views of Anders Sparrman* and Le Vaillant, some of his own observations were inaccurate, probably because he added them to his manuscript from memory several years after his visit. Other technical topics discussed are his sailing instructions for visiting seamen, and his own, rather inaccurate, measurements of Table Mountain.