make the Calculation. It must be confess'd, that the Aer of those Climates, is not so pure and Desecate as those which are neerer the Tropicks, where the Continent is lesse ragged, and the Weather more constant and steady, as well as the Inclination and Temper of the Inhabitants.
But it is not here that I pretend to speculate upon these Causes, or nicely to examine the Discourses of the Stoicks and Peripateticks, whether the Aer be in it self, generally cold, humid, warm or exactly temper'd so as best conduces to a materiall principle, of which it is accounted one of the four; because they are altogether Physicall notions, and do not come under our cognisance as a pure and sincere Element; but as it is particularly inquinated, infected, participating of the various Accidents, and inform'd by extrinsecal Causes, which render it noxious to the Inhabitans, who derive and make use of it for Life. Neverthelesse, for distinction sake, we may yet be allow'd to repute some Aers pure comparatively, viz. That which is cleare, open, sweetely ventilated and put into motion with gentle gales and breezes; not too sharp, but of a temperate constitutution. In a word, That we pronounce for good and pure Aer, which heat not to sweats and faintnesse; nor cooles to rigidnesse and trembling; nor dries to wrinkles and hardnesse; nor moystens to resolution and over much softnesse. Lib. de Aere Aqu. & Locis.The more hot promotes indeede the Witt, but is weak and trifling; and therefore Hippocrates speaks the Asiatique people Imbelles and Effeminate, though of a more artificiall and ingenious Spirit: If over cold and keen, it too much abates the heat, but renders the body robust and hardy; as those who are born under the Northern Bears, are more fierce & stupid, caused by a certain internal Amiperistasis and universal Impulsion. The drier Aer is generally the more salutary and healthy, so it be not too sweltery and infested with heat or fuliginous vapours, which is by no means a friend to health and Longevity, as Avicen notes of the Æthiops who seldome arived to any considerable old Age. As much to be reproved is the moyst, viz, that which is over mix'd with aqueous exhalations, equaly pernicious and susciptible of putrefaction; notwithstanding does it oftner produce faire and tender skins, and some last along while in it; but commonly not so healthy, as in Aer which is more dry. But the impure and Uliginous, as that which proceedes from stagnated places, is of all other, the most vile and Pestilent.
