and a Contagion, 37 well as they are pernicious : But enough of thefe Matters. A T length then it becomes neceflary to change the Confideration, and enquire how it comes that the Plague hath its chief Origin from an Alteration or Corruption of the nitrous Spirits in the Air : This is the great Difficulty ! This is our Task ! It is therefore to be hoped that the Novelty of the Opinion will not occafion any one to receive it at fir ft Sight amifs, until by due Examination he hath brought it to Trial ^ but in Order to erecl this upon a fure Foundation, it is proper to premife fome ■ Confiderations. AND firft of all, the central nitrous Spirit in the Earth does everywhere tranfpire and exhale towards the Surface, to recruit the Confumptions of Nature, and for other Pur- poles hereafter to be mentioned. From this faline Origin, {training through the Bowels of the Earth, every one under- ftands Vegetation to be carried on, and that the Light and vital Warmth of the Sun is impregnated by it th ojgh the whole Region of Air ^ and the mutual Intercourfes or Operations upon one ano- D 3 ther.
