1670. But whether they may not have been from one of the satellites of Jupiter, which, like [our] moon, are surrounded by a different kind of atmosphere [from their primary], and thus that these spirits are a different kind of creatures in such a little world, and possessed of another kind of bodies, I am not sure, though they intimated to me something of the kind; for as I could not have an idea of any sort of men except such as live on earths surrounded by atmospheres, therefore, although ignorant of the positive fact, yet I would not decidedly reject the supposition, for corporeal forms are governed entirely by the state of the atmospheres, and many other things pertaining to the earths in which they dwell. - 1748, March 23.