the whole Caravan, are to obey
you, till you have pass'd the Atmosphere, when you and they are to
follow the Directions of _Volatilio_, in what regards the Way only;
but, in Case that you can respire on the Top of the Mountain, order
_Volatilio_ to precede you a Day's Ascent, return the next, and
immediately dispatch a second Messenger with the Account he gives,
and continue on the Mountain for farther Instructions, before you
proceed, should it prove practicable. I need not tell you the
Publick must be amused with Hopes of Success, tho' you have Reason
to despair of it; nor need I even hint to you what Method you ought
to take. I wish you Health, and that your Conduct may answer my
Expectations."

I acted pursuant to these Instructions, and sent _Volatilio_ forward,
who reach'd the Top of the Hill; but finding the Air too thin to
continue there, without the Help of humected Spunges, he therefore sent
those back he carried with him to the mid Space of the Mountain, and an
Express to me, by which he informed me what he had done; that he
resolved to continue there a natural Day, and then join me where he had
sent his Followers, to which Place he desired I would ascend, and defer
the dispatching any Express to his Majesty, till he saw me again.

I ascended to the Mid-space, and found a vast Alteration in the Air,
which even here was very sensibly rarified.

My Projector came to me at his appointed Time, and told me he did not
question the Success of our Enterprize, since he imagined the Air above
the second Region rather denser than that near the Earth, and hoped the
Cold was not more intense than on the Mountain's Top; and that if this
prov'd so, we cou'd breathe and support the Cold with little Difficulty.
I answer'd, that it was natural to conclude the Air next the Earth more
dense than that above it, as the weightiest always descends the first.

"That Reason, _said he_, is not conclusive, for the Air immediately
encompassing the Earth, is more sensible of its attractive Power,
than that at a greater Distance, as you may be satisfied, in placing
two Pieces of Iron, one near, and the other at a Distance from the
Loadstone; the nearest Piece will be strongly attracted, while that
at a greater Distance is but weakly affected. Now supposing the Air
only of an equal Density thro'out when we have left the Earth,
(which, by the Reflection of Heat from the Mountains, rarifies the
cir