Chapter XXIII

_If it begins to rain an Hour or two before Sun-rising, it is like to be fair_ before Noon, and so continue that Day, _but if the Rain begin an Hour or two after Sun-rising, it is like_ to Rain all that Day, _except the Rainbow be seen before it rains_.

THIS is a short, clear, and easy Observation, and therefore I shall not dwell long upon it, but rather entertain the Reader with a few Observations on the Rainbow. Whenever it appears, things are thus circumstanced. The Spectator has the Sun behind him, and Clouds with the Bow in them before him. Sometimes there are two and even three Bows seen, but this is very rare. The Colours in the Bow are ranged in this Order, _viz._ Violet, Purple, Blue, Green, Yellow, Orange, Red. After a long Drought the Bow is a certain Sign of Rain, if after much Wet fair Weather. If the Green be large and bright it is a Sign of Rain, but if the Red be the strongest Colour, then it denotes Wind and Rain together. If the Bow breaks up all at once there will follow serene and settled Weather. If the Bow be seen in the Morning small Rain will follow. If at Noon, settled and heavy Rains; if at Night, fair Weather. The Appearance of two or three Rainbows shews fair Weather for the present, but settled and heavy Rains in two or three Days' Time.

LUNAR Rainbows are sometimes, but very seldom seen, they are extremely beautiful, but much less than those that appear in the Day time, and a yellow, or rather a straw Colour prevails most. As they happen so seldom, they cannot well be reckoned amongst the Signs of Weather. But now, after speaking of so many different Methods of judging when rainy Weather will be of a short or long Continuance: Give me leave to describe two or three Instruments easily made, which will shew the Alterations of the Weather certainly, constantly, and early enough for most Uses.

THERE were some Years ago a Sort of Toys sold, with a Man and a Woman so fixed before the Door of a House, that at the Approach of wet Weather the Woman entered it, and when the Weather grew fair the Man. This was done by the Help of a Bit of Catgut, which shrinks in wet Weather, and stretches again when it is fair. This appears better by a Line and Plummet, especially if the Line be made of good Whipcord, that is well dried, for then if it be hung against a Wainscot, and a Line drawn under it exactly where the Plummet reaches, in very moderate Weather it will be found to rise above it before Rain, and to sink below when the Weather is like to become fair; but the best Instrument of all is a good Pair of Scales, in one of which let there be a brass Weight of a Pound, and in the other a Pound of Salt, or of Salt-Petre well dried, a Stand being placed under the Scale, so as to hinder its falling too low. When it is inclined to rain the Salt will swell, and sink the Scale, when the Weather is growing fair, the brass Weight will regain its Ascendancy.