A Treatise on the Synochus Atrabiliosa, a Contagious Fever, Which Raged at Senegal in the Year 1778, and Proved Fatal to the Greatest Part of the Europeans, and to a Number of the Natives: To Which Is Prefixed, a Journal of the Weather during the Prevalence of That Disease, with Remarks on the Country, Formerly Read at the Royal Society; and Annexed to It, a Short Reflection on the Gum Trade of Senegal, and the Importance of the Place on That Account; Concluding with an Argument Concerning the Bad Consequences Which Must Attend the Present Mode of Sending Convicts to Africa for Soldiers