Part 6

IT is observed that it thunders most when the Wind blows from the South, and least when it blows from the East. The great Principle of Thunder is Sulphur, as is evident from the Smell it leaves behind it; but in order to occasion such an Explosion, there must be other Ingredients mixed therewith, especially Nitre, of which the Air is always full, besides other Things, of which it is impossible to give any Account. The Tracts of this Sort of Matter fly about in the Air, and are as it were Lines of Gunpowder, and as in the firing of that Powder, the Fire begins at one End, and pursuing its Aliment proceeds to the other Extremity, and so the whole Mass of Powder is fired; we may from thence account for the Phaenomenon of Thunder. For in like Manner those inflamed Tracts which are suspended in the Air, flash from a Flame that runs from one Extreme to the other, wherever the Vein of Nourishment leads it. Hence those Rays of Thunder, which seem to be brandished through the Air, and sometimes to be split in two or more Tracts, and sometimes to return back, at other Times to be projected in Lines that are joined by various Angles, and this only because the Flame meets with Tracts lying in various Situations that cohere one with another. Therefore Thunder seems now to run horizontally, now from above downwards, now upwards from the Earth, for if the Matter of Thunder pressing out of the Earth is enflamed near the Ground, the Flame darting upwards, the Thunder will seem to be projected out of the Earth. If the same Tract be set on Fire at its upper end, the Flame will move downwards, and the Thunder will seem to descend out of the Sky.

HENCE we easily understand how it comes to thunder oftener in one Place than another, but most frequently in those where the Soil produces odoriferous Herbs, and abounds with Sulphur, and where the People are much exposed to the extreme Heat of the Sun. Thunder is less frequent in Places where there are few odoriferous Herbs, very little Sulphur, or where the Climate is watery and moist. For Instance, it thunders very much in Italy and Sicily, and very rarely in Egypt, and the adjacent Countries. If it be demanded how it comes to thunder in the midst of the Ocean? The Answer is easy, because from the Bottom of the Ocean vast Tracts of sulphureous Matter are cast up through the Waters; as it happens to spring Waters in several Places, the Streams of which will take Fire from a lighted Candle. For sulphureous Exhalations bursting out together with the Waters, the fulmineous Matter in the Air is set on Fire when it meets with Exhalations or Vapours with which it can excite a vehement Effervescence. It is very clear from this Account, that the Clouds mentioned at the Top of the twenty-eighth Page are thunder Clouds, or Clouds big with the Materials of Thunder.

XIX.

If two such Clouds arise, one on either Hand, it is Time to make haste to shelter.

AS this Observation is of the same Nature with the former, we shall continue our Remarks. The Reason why it seldom thunders in Winter is, because the exterior Parts of the Earth are so contracted by the cold Snow and Ice, that Sulphur cannot perspire in any great Quantities, but as soon as the Earth begins to be opened by the Sun in the Spring, something expires in the Month of April which takes Fire. But by the greater Heat of the Sun penetrating deeper into the Earth, the Cortex is more opened in May, and now there is a more copious Expiration of the fulminating Matter, and whatever was collected and shut up in Winter, is now released and snatched up in the Air, and thence proceeds the most frequent Thunders in the Month of May, and chiefly when a very hot Day or two has gone before. A less Quantity of the same Matter remains in the upper Cortex of the Earth for the Month of June, but in the mean Time a Stock arises out of the deeper Bowels of the Earth, which is attenuated and prepared, so that by the very fervent Heat of July it is elevated, as it were in heaps, and set on Fire. Hence Thunder is as frequent in July as in May. And the Heat decreasing in the succeeding Months, the Exhalation of the fulminating Matter out of the Earth is more sparing, and thence, also, the thunder is less frequent, till in October, and the other winter months, the earth is bound up with us, and hardly expires any more. Hence we see why it very seldom thunders when the northerly winds blow; for these winds constringe the earth with their cold, and so hinder the fulminating matter from bursting forth; and when they are burst forth and floating in the air, they hinder their effervency. But on the contrary, when the warm and moist south winds blow, which open every thing, the earth likewise is opened, and abundance of fulminating matter is expired and ascends on high, which is there easily inflamed.

AS the flame runs very swiftly, it seems to carry along with it particles, which it could not so easily set on fire, and when any of these particles are drawn together, and heated to a certain degree, they at last take fire, with a sudden and great explosion, and thereby produce what we call a thunder Clap. Now, though this be only a single sound, yet it is often heard in the form of a great murmuring noise of a long continuance; sometimes for thirty or forty seconds, because of its various repercussions by the clouds and terrestrial obstacles. Hence it is, that in vales, which are surrounded by mountains of a different Height, there is a terrible and long continued Bellowing of thunder Claps. Whereas for one Explosion it has been observed that there is but one Clap. Yet however if the Flame set Fire to two, three, or more fulmineous Tracts, each of them at last will end in a Clap, and thus several Sounds may be heard together, or quickly succeeding one another.

XX.

If you see a Cloud rise against the Wind or side Wind, when that Cloud comes up to you, the Wind will blow the same Way that the Cloud came. And the same Rule holds of a clear Place, when all the Sky is equally thick, except one clear Edge.

THIS seems to arise from hence, that Wind being nothing more than Air in motion, the Effects of it first discover themselves above, and actually drive such Clouds before them. This was long ago observed by Pliny. When Clouds, says he, float about in a serene Sky, from whatever Quarter they come, you may expect Winds. If they are collected together in one Place, they will be dispersed by the approach of the Sun. If these Clouds come from the North East, they denote Winds; if from the South great Rains. But let them come from what Quarter they will, if you see them driving thus about Sunset, they are sure signs of an approaching Tempest.

IF the Clouds look dusky, or of a tarnish silver Colour, and move very slowly, it is a Sign of Hail. But to speak more plainly, those very Clouds are laden with Hail, which if there be a Mixture of Blue in the Clouds will be small, but if very yellow, large. Small scattering Clouds that fly very high, especially, from the South West, denote Whirlwinds. The shooting of fallen Stars through them, is a Sign of Thunder. We meet with many Observations of this sort in our old Writers on Husbandry, and we have abundance of Proverbs relating to this Subject which are worth observing, and the rather, because most of them are not peculiar to our Language only, but common to us with many of our Neighbours. It is the Remark of Lord Bacon, and a very judicious Remark too, that Proverbs are the Philosophy of the common People, that is to say, they are trite Remarks founded in Truth, and fitted for Memory. I must confess that there are some of them that seem either false, or of no great Consequence, but then I am apt to suspect, that by various Accidents we have lost their true Meaning, or else, that in length of Time, they have been altered and corrupted, till they have little or no meaning at all.

I cannot help taking Notice in Regard to the Rule before us, that Captain Dampier tells us in the East-Indies, they have always Notice of a Tuffoon by the Skies being first clear and calm, and then a small white Cloud hanging precisely in the Point from whence the Storm comes, where he observes that it remains sometimes twelve Hours or more, and adds, that as soon as it begins to move, the Wind presently follows it. When Sir John Bury, who died an English Admiral, had the Command of a small Frigate in the West-Indies, he escaped a Hurricane in the Leward Islands by taking the Advice of a poor Negro, who shewed him a small white Cloud at a Distance, and assured him that when it came to the Zenith, the Hurricane would infallibly begin, as indeed it did.

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.

XXII.

If it begin to Rain from the South, with a high Wind for two or three Hours, and the Wind falls, but the Rain continues, it is like to rain twelve Hours or more, and does usually rain till a strong North Wind clears the Air. These long Rains seldom hold above twelve Hours, or happen above once a Year.

THIS depends entirely upon Observation, and Experience shews us that whenever the Wind falls, Rain follows. It has been likewise observed, that when the Wind changes often there fall heavy Rains. All these Alterations in the Atmosphere, are less observed by Men than by Animals, for two Reasons. The first is, that we live much within Doors, by which they are less obvious to us, and it is for this Reason that the Husbandman, Seamen, Fishermen, but above all Shepherds, who are more in the open Air than other Men, are better acquainted with, and more able to distinguish and judge of the Signs of the Alteration of the Weather, than those who live altogether within Doors, or go out but seldom. Another Reason is our having so many Things to mind, which takes off our Thoughts, and renders us less attentive to the Signals which would give up Notice of such Alterations. It is for this Reason that we ought to serve ourselves of that Sort of Instinct which Nature has given to other Animals, and which as it is a Gift of Nature, is in a Manner infallible.

THUS if small Birds prune themselves and duck and make a shew of washing. If Crows make a great Noise in the Evening, if Geese gaggle more than usual, these are all Signs of Rain, because these Animals love wet Weather, and rejoice at the approach of it. On the other Hand, if Oxen lie on their Right Sides, look towards the South, and lick their Hoofs, if Cows look up in the Air, and snuff it, if Asses bray violently, and if Cocks crow at unusual Hours, but especially when a Hen and Chickens crowd into the House, these are sure Signs of Rain.

INSECTS also are very sensible of such Changes of Weather. Frogs croak more than ordinary, Worms creep out of the Ground, Moles throw up more Earth than usual, because such Weather is more agreeable to them; Hornets, Wasps, and Gnats, sting more frequently against wet Weather than in fair. Spiders are restless and uneasy, and frequently drop from the Wall, the humid Air getting into their Webs and making them heavy. But the surest and most certain Sign is taken from Bees, which are more incommoded by Rain than almost any other Creatures, and therefore, as soon as the Air begins to grow heavy, and the Vapours to condense, they will not fly from their Hives, but either remain in them all Day, or else fly but to a small Distance.

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.

XXIV.