Chapter XXI

_Sudden Rains never_ last long: _But when the Air grows thick by Degrees, and the Sun, Moon, and Stars shine dimmer and dimmer, then it is like_ to rain six Hours usually.

RAIN is, properly speaking, a Multitude of small watery Drops, falling from the upper Air at different Seasons. When the upper Regions become cold of a sudden, the watery Clouds are condensed and fall in hasty Showers. It is observed that mountainous Countries have most Rain, and the Reason seems to be the Winds driving the Clouds against the Rocks and Hills, and thereby compressing them in such a Manner, that they are immediately dissolved, and fall as it were at once. This is the Reason that in _Lancashire_ there falls twice as much Rain as in _Essex_, and it is probably from the same Cause, that in the Ocean, over-against the mountainous Coast of _Guinea_, showers sometimes fall as it were by Pailfuls.

THIS Observation of our Shepherd is very just and reasonable, and I dare say will hardly ever fail such as observe it. The Dimness of the Stars and other heavenly Bodies, is one of the surest Signs of very rainy Weather. It is likewise to be observed that when the Stars look bigger than usual, and are pale and dull and without Rays, this undoubtedly indicates that the Clouds are condensing into Rain, which will very soon fall; and it has been observed that when the Air grows thick by Degrees, and the Light of the Sun lessens so as not to be discerned at all, and again when the Moon or Stars have the same Appearances, a continued Rain for at least six Hours is sure to follow.

TO be the better informed in such Cases, it is best to have Recourse to a variety of Signs, for it is not only the Clouds and Sky, or the Sun, Moon, and Stars, that gives us previous Notice of rainy Weather, but almost every Thing in the Creation, and Vegetables particularly. As for Instance, the Pimpernel, which is a very common flower, shuts itself up extremely close against rainy Weather. In like manner the Trefoil swells in the Stalk against Rain, so that it stands up very stiff, but the Leaves droop and hang down. Even the most solid Bodies are affected by this Change of the Atmosphere, for Stones seem to sweat, and Wood swells, the Air driving the moist Particles with which it is filled into the Pores of dry Wood especially, makes it swell prodigiously, and this is the Reason the Doors and Windows are hard to shut in rainy Weather.

THIS is so true, that there has been a Method found of dividing Mill-stones by the mere Force of the Air, which is done in this Manner. They divide a Block of this kind of Stone as big as a large rolling Stone, into as many Parts as they design to make Millstones, and in the Circles where this Block is to be divided, they pierce several Holes, which they fill with allow Wood dried in an Oven, and expose the Stone to the Air, in moist Weather; when the Wood swells to such a Degree as to split the Stone as effectually, as if it was by iron Wedges driven by Sledge-Hammers. This curious and extraordinary Method of dividing Mill-stones is related by the famous Mr. _Ozanam_ of his own Knowledge.