_B._ There is no spring upon the very top of a hill, unless some natural pipe bring it thither from a higher hill. _A._ Julius Scaliger says, there is a river, and in it a lake, upon the top of Mount Cenis in Savoy; and will therefore have the springs to be ingendered in the caverns of the earth by condensation of the air. _B._ I wonder he should say that. I have passed over that hill twice since the time I read that in Scaliger, and found that river as I passed, and went by the side of it in plain ground almost two miles; where I saw the water from two great hills, one on one side, the other on the other, in a thousand small rillets of melting snow fall down into it. Which has made me never to use any experiment the which I have not myself seen. As for the conversion of air into water by condensation, and of water into air by rarefaction, though it be the doctrine of the Peripatetics, it is a thing incogitable, and the words are insignificant. For by densum is signified only frequency and closeness of parts; and by rarum the contrary. As when we say a town is thick with houses, or a wood with trees, we mean not that one house or tree is thicker than another, but that the spaces between are not so great. But, since there is no vacuum, the spaces between the parts of air are no larger than between the parts of water, or of any thing else. _A._ What think you of those things which mariners that have sailed through the Atlantic Sea, called _spouts_, which pour down water enough at once to drown a great ship? _B._ It is a thing I have not seen: and therefore can say nothing to it; though I doubt not but when two very large and heavy clouds shall be driven together by two great and contrary winds, the thing is possible. _A._ I think your reason good. And now I will propound to you another experiment. I have seen an exceeding small tube of glass with both ends open, set upright in a vessel of water, and that the superficies of the water within the tube was higher a good deal than of that in the vessel; but I see no reason for it. _B._ Was not part of the glass under water? Must not then the water in the vessel rise? Must not the air that lay upon it rise with it? Whither should this rising air go, since there is no place empty to receive it? It is therefore no wonder if the water, pressed by the substance of the glass which is dipt into it, do rather rise into a very small pipe, than come about a longer way into the open air. _A._ It is very probable. I observed also that the top of the inclosed water was a concave superficies; which I never saw in other fluids. _B._ The water hath some degree of tenacity, though not so great but that it will yield a little to the motion of the air; as is manifest in the bubbles of water, where the concavity is always towards the air. And this I think the cause why the air and water meeting in the tube make the superficies towards the air concave, which it cannot do to a fluid of greater tenacity.