sun; which frequently, for an hour or two at noon, dispels the clouds, and with its direct beams instantly changes the refreshing coolness of the air into a heat almost insupportable? “Further: As the season of those sudden and terrible storms, called the hurricanes, in the East and West Indies, and tornadoes on the coast of Guinea, partly coincides with that of the rains, do these dreadful tempests in any measure contribute to produce the prevailing sickness at those times? It was remarkable one year at Senegal, that, in the beginning of the rainy season, in the night succeeding one of these tornadoes, a great number of the soldiers, and two thirds of the English women, were taken ill, this garrison before having been uncommonly healthy. “Lastly: Is it not more probable, as in those countries the earth for six or eight months in the year receives no moisture from the heavens but what falls in dews, which every night renew the vegetation, and reinstate the delightful verdure of the grass, that the surface of the ground in many places becomes hard and incrustated with a dry scurf, which pens up the vapours below, until, by the continuance of the rains for some time, this crust is softened, and the vapours set free? That these dews do not penetrate deep into the surface of the earth, is evident from the constant dryness and hardness of such spots of ground, in those countries, as are not covered with grass and other vegetables. Thus the large rivers, in the dry season, being confined within narrow bounds, leave a great part of their channel uncovered, which, having its moisture totally exhaled, becomes a hard, dry crust; but, no sooner the rains fall, than, by degrees, this long parched up crust of earth and clay gradually softens, and the ground, which before had not the least smell, begins to emit a stench, which in four or five weeks becomes exceeding noisome; at which time the season of sickness commences.” From these quotations it must certainly appear, that the author himself is dissatisfied with his theory; and that, though in the outset he thought heat and moisture, assisted by the exhalations from putrid animal and vegetable substances, sufficient to produce the disorders of which he treats, yet, on a more minute investigation, he is obliged to acknowledge, that something inexplicable still remains. This he now wishes to solve by unknown properties in the water, by confined exhalations, &c. But as the consideration of these things belongs properly to the next section, I shall here only remark, that there hath not yet been given any satisfactory account of the origin of epidemic diseases of what I call the _inferior_ kind, much less of the true plague, which stands above them all, as I have already said, like the serpent Python above other serpents.