“Mark, with attentive eye, the rapid sun—The varying moon that rolls its monthly round;So shalt thou count, not vainly, on the morn;So the bland aspect of the tranquil nightWill ne’er beguile thee with insidious calm.”
All early condensation and indications derived from it, must be looked for in the west. From that quarter all storms come. These indications at nightfall are of a varied character. They may consist of primary condensation in the trade, or of secondary condensation, scud running north toward a storm, the condensation of which has not yet visibly reached us, but which will extend south and pass over us. It may be a heavy bank, or consist of narrow cirrus bands. Cirro-stratus cloud banks, in the S. W., in the fall and winter, of a foggy and uniform character, are indicative of snow. The body of the storm will pass south of us, and a portion over us, the windbe north of east, and the snow will not be likely to turn to rain before it reaches the earth, by reason of a southern middle current.
Banks in the N. W. indicate rain at all seasons. The storm is north of us, working southerly, and such storms rain on the southern border—in winter even—because they have the wind on that border from south of east. It may, indeed, snow, but if so, probably in large flakes, soon turning to rain. There are other appearances at nightfall which deserve consideration. A red sun, with smoky air, is indicative of continued dry weather, a frequent appearance in dry terms, lasting three or four days, at least, from the commencement. So is a red appearance of the sky, when there are no clouds, indicative of a fair day following. On this subject we have an allusion to the weather, by our Saviour while on earth, which, like all such allusions found in the Bible, is of remarkable philosophical accuracy. It is found in Matthew, chapter xvi., verses 2 and 3: “He answered and said unto them, When it is evening ye say, It will be fair weather, for the sky is red. And in the morning, It will be foul weather to-day, for the sky is red and lowering. O, ye hypocrites, yecan discernthe face of the sky,” etc.
Another allusion to the weather, though not applicable to this point, I will refer to in passing. It is found in Luke, chapter xii., verses 54 and 55: “And he said also to the people, When ye see a cloud rise out of the west straightway ye say, There cometh a shower; and so it is. And when ye see the southwind blow, ye say, There will be heat; and it cometh to pass.”
This is all very true, and might have been cited to show the universality of the phenomena. But to return.
We have an old English proverb alluding to the same phenomena, of great value and truth, viz.:
“An evening red and a morning grayAre sure signs of a fair day;Be the evening gray and the morning red,Put on your hat or you’ll wet your head.”
The sky is red if there be no condensation at the west to obscure the rays of the sun; if there be, it is gray, or there is a bank or cloud, and it is obscured. So if there be no condensation over, or to the east of us, in the morning, to reflect the rays of the sun, the sky is gray; if there be such condensation, the sun is reflected from it, and the sky is red. Such morning condensation is indicative of foul weather. It is, as we have said, the eastern edge of an approaching storm, on, or under which, the sun shines and illumines it. Thus, at night, it shines through a portion at the west, which is situate between the sun and us, making the sky gray: but shines on, or under, a portion in the morning, east of us, but not far enough east to obscure the horizon, and the rays of the rising sun are reflected from it. In either case the red or gray appearance results from the relative situation of the sun and the eastern edge of an approaching storm.
The following couplet of Darwin is an apt description of the morning appearance:
“In fiery red the sun doth rise,Then wades through clouds to mount the skies.”
The sun is often reflected in vivid colors, from the under surface of clouds, at sunset. This is an indication of fair weather. It is evident the sun shines through aclear atmosphere beyond the cloud, or his rays would not reach and illume the lower surface of the cirro-stratus with such distinctness. He “sets clear,” as is said; the clouds are passing off, and there are none beyond. It is this appearance, in different forms, when there happen to be patches of broken, melting cirro-stratus above the horizon, which makes the beautiful sunsets that attract attention. So the sun is reflected, in beautiful colors sometimes, from the cumulus clouds which have passed over to the east. The most beautiful and variegated I have ever seen, were reflected from that imperfect cumulus condensation which takes place occasionally during long drouths—doubtless resembling that which is seen over Peru, hereinbefore alluded to, as described by Stewart.
It is not, then, the presence of cloud condensation at the west, at nightfall, which alone indicates foul weather; but such condensation, whatever its form, as evinces that it is not thedissolvingcloud of the day, but the eastern, approaching portion of astill denser portion beyond, through, or under which, the sun can not shine clearly, but which wholly or partially obscures it.Remembering this philosophy of the matter, the observer will soon be able to detect the various forms of condensation which originate or exhibit themselves at nightfall, and whether they indicate an approaching storm or not, without a more explicit specification of them. It is an important hour for observation; “Let not the sun go down” without attention.
When the condensation is obvious, but thin, at nightfall, it may not, as I have said, be discernible in the evening. But there are methods by which the incipient storm condensation may be detected. The number of the stars visible, and thedistinctnesswith which they may be seen, indicate the absence or presence of condensation and its density. Virgil, alluding to the indications of fair weather, says:
“Brightlythe stars shine forth; Cynthia no moreGlimmersobnoxious to her brother’s rays;Nor fleecy clouds float lightly through the sky.”
The brightness of the stars and the clear appearance of the moon show the absence of condensation and thedissolutionof the fleecy clouds at the close of the day is, as we have seen, always a fair-weather indication.
There is much true philosophy in the allusions of Virgil to the moon. Thus—
“When Luna first her scatter’d fires recalls,If withblunt hornsshe holds theduskyair,Seamen and swains predict th’ abundant shower.”
The horns, or angles of the moon will, of course, appear distinct and sharp or indistinct and blunt, inproportion to the amount of condensation in the atmosphere which impedes the passage of the light. For the same reason, when the moon is new, her entire disk is visible when the atmosphere is very clear, by reason, as is supposed, of light reflected from the earth to the moon and back to us. This double reflection can only take place when the atmosphere is very clear. Hence, Virgil alludes to it, and correctly, as an indication of continued fair weather:
“If (mark the ominous hour!)The clear fourth night her lucid disk define,That day, and all that thence successive spring,E’en to the finished month, are calm and dry.”
Probably Virgil alluded to a month of the summer trade-wind drouth which reaches up on Southern Italy. But that appearance of the moon is occasionally seen here, and the indication is, in degree, philosophically true.
It is somewhat more difficult to determine what will be the result of the condensation seen at the west in the morning, and which is not so far east, or of such a character, as to reflect the rays of the sun; for, although always suspicious, it is sometimes of a foggy character, and disappears between eight and nine o’clock. If it increases in density after ten o’clock, or is of a dense cirro-stratus character, rain may generally be expected. If of a decidedcirro-cumuluscharacter, it is certain to disappear. Cirro-cumulus is seen in small patches, with small, distinct, and rounded masses, in summer, in the morning, andsometime, during the day, after high fog has disappeared, and at other times, and is always, when of thatdistinctcharacter, a fair weather indication. I have seen it thus when the wind was blowing from the N. E., and the scud running toward a storm passing near, but to the south of us, when those who relied upon the existence of the wind and scud as evidences that we were to have the desired rain, were deceived. Thus, the couplet from an old almanac:
“Ifwoolly fleecesstrew the heavenly way,Be sure no rain disturb the summer day.”
When this morning condensation is not high fog, and is dense and passing east with a wavy appearance, it is very certain to rain. Jenner says:
“The boding shepherd heaves a sigh,For see, a rainbow spans the sky.”
An old almanac had the following verse:
“A rainbow in the morningIs the shepherd’s warning;A rainbow at nightIs the shepherd’s delight.”
So the proverb was originally made; but as our ancestors were not shepherds, and had a horror of ocean storms, it was commonly quoted, in this country, in the following form:
“A rainbow in the morning,The sailors take warning,” etc.
Rainbows are not reflected fromclouds, but falling rain, and a morning rainbow at the west is, of course, evidence that it isactually raining there, and will, in all probability, pass over us. “Thunder in the morning, rain before night,” is a common saying, and a true one. There is a belt of showers, or showery period approaching, of unusual intensity—for thunder showers in the morning are rare. The afternoon is their most common period, and they are very apt to appear then, when the morning is showery.
Of the different forms of cirrus and cirro-stratus, which appear during the day, and indicate approaching storms, or of cumulus indicative of showers, it is difficult to give an intelligible description without very many illustrations. I have many daguerreotype views, taken at different seasons of the year, and at a time when different forms of cirrus and cirro-stratus condensation, indicative of storms, exhibited themselves. They differ, as I have said, and it must be remembered, very much atdifferent seasonsof the year, and indifferent years, and their delicate shades are taken with difficulty by the artist, and reproduced with difficulty, and only at considerable expense, by the engraver; and I have omitted them. The time will come when a knowledge of their language will be sought for and read—when the “countenance of the sky” will be an object of intelligent interest to all whose business may be affected by the weather, or who love to learn of nature. But it is not yet. This is the age of theory and speculation. The time of actual, practical, connected observationand prognostication, which may justify expensive illustration, is yet to arrive.
The reader will find in the general plates representations of several kinds of cirri. They are delicate, always white, more or less fibrous, and form in the upper part of the trade or the adjoining atmosphere above it. Their character and elevation should be studied, and the observer should be careful to distinguish which is the most elevated. Not unfrequently it may seem, to a hasty observer, that the cirrus is below the cirro-stratus or forming stratus. But the genuine cirrus never is. It forms near, and above, the point of congelation, and is often composed of crystals of ice or snow. If they fall, they melt and evaporate, when there is no storm, before reaching the earth. Aeronauts have met with them and their crystals when there was no fall of moisture at the surface of the earth; and the angles of reflection exhibited by halos and other optical phenomena which form in them, enable us to detect their crystallization and the form of it.
They are produced by electric changes which condense the vapor, and the coldness of the air at that elevation freezes it at theinstant of its condensation.
Congelation is crystallization, and all crystallization is electric, or magneto-electric. The snow-flakes differ in form and size according to the suddenness of the condensation, the amount of moisture condensed, the polarity of the strata through which they pass, and their consequent attraction and adhesion to each other.
The connection of electricity with these formations of cirri has frequently been admitted, and it is perfectly obvious that the long fibrous bands, shooting from horizon to horizon, could not be formed by commingling of currents any more than the perfectly isolated, distinct, enlarging-outward cumulus hail-storm, could be so formed. Cirri form at the line of meeting, between the trade and the upper atmosphere, and in one or the other, or both, very much according to the season, and the suddenness with which storms are produced. These ofteninducea layer of cirro-stratus or stratus at the lower line of the counter-trade, and in the surface-atmosphere, which precipitates; and this operation is clearly discernible, and very frequently, before gentle rains. Condensation in the whole body of the trade is usually in the form of turbidness or mistiness, a bank or incipient stratus, without cirri.
It seems matter of astonishment that water should float so far condensed, in strata where the air is so much lighter, without being precipitated. But electric attraction and repulsion between the different strata and the vesicles, explain it.
In mid-winter, the cirrus forms are prevalent and most distinct. After severe cold weather, when a storm approaches, the cirri form in long, narrow threads, parallel to each other, extending from about W. S. W. to E. N. E., gradually thickening and forming, or inducing, cirro-stratus and stratus, and dropping snow. This form is called thelinear-cirrus. The tufted, and other fibrous forms, are seenin patches also, in great distinctness, during these mid-winter days, when the wind gets around to the southward, and the weather is pleasant. Such days are called “weather-breeders,” and theiroffspringthe patches of cirrus, which are to extend and compose, or induce the storm, and indeed are an advance part of it, are then never absent. A clear, moderate day, in a normal winter, with wind from any southern point, however light, between the 1st of January and the middle of February, without these patches of cirrus, is very uncommon. Watch and see whether they tend to cirro-stratus, or whether the wind gets around to the N. W. at nightfall, and they disappear. If the former, a storm may be expected; if the latter, fair weather.
Thus there are three peculiarities attending the forming cirrus of mid-winter (1st of January to 10th of February): long, fibrous, parallel bands in the morning (linear cirrus), gradually coalescing as the day advances, after severe cold; the comoid, curled, or tufted cirrus, in curling bunches, called “mares’-tails,” and thetransverse, when the fibers are in bands or threads, which are not parallel, but cross each other at angles, more or less acute. The two former varieties are represented on Figure 5, page26, indicated by one bird, but the last form is a very prevalent one in our atmosphere.
Various names have been given to different forms ofcirro-stratus. Those represented in Figure 5, page26, are the “cymoid” on the right, the “mottled” on the left, below the cirro-cumulus; and the “linear”below that. The form known as the “mackerel sky” is not represented there. It consists of regular forms, resembling thewaveson the surface of the water when the wind blows a gentle breeze. But thewavyform, and of all sizes, is very frequently assumed by cirro-stratus, which is rapidly condensing, and turning to stratus. In the “mackerel sky,” strictly so called, the waves are small, parallel, nearly distinct and equi-distant, and resembling the appearance of a school of mackerel, swimming in the same direction, one above another. Allwavyforms of cirro-stratus indicate a disposition to increased condensation and rain. When the waves are very large and dense, and cross obliquely, or unite at one end, rain is very certain to fall soon, if the line of progress of the condensation is over the observer, and the clouds are seen in the western or N. W. quarter of the sky.
But there are few forms which are not occasionally seen when no rain or snow falls. The intensity of the electric action which produces them may not be sufficient to effect precipitation, or they may be the attendant, attenuatedlateralcondensation, which frequently “thins out” a considerable distance from the dense, precipitating portions of the storm.
If that denser portion is north of us, the probabilities of rain are greater, for there is always a probability that the storm may be of the character which is extended south, by a polar wave. The observer must watch the formation of cirri, and the different forms of cirro-stratus and stratus, and become familiar with their appearance. It is not a difficult task.With the aid of a few general directions he will soon be familiar with them:
1. Get a correct idea of the different characters of the primary clouds. The true fibrouscirrus—the different forms ofcirro-stratus—the smooth, uniformstratus—thecirro-cumulus, which is nothing but a cirro-stratus, separated intodistinct massesby the repulsion of static electricity—and thecumulus, too distinct ever to be mistaken. There is no difficulty, except with the varied forms of cirro-stratus. It is useless to attempt to give, or the observer to rely on, names for these numerous forms, without as numerous illustrations. Those in use are rarely applied correctly. I have never met with ten persons who applied even the term “mackerel sky” to the same precise form of cirro-stratus. In relation to all of them it is to be observed that polar belts of condensation, and local appearances of considerable extent, are often too feeble in action to precipitate, even when the mackerel form is present; and all may be the lateral attendants of passing storms. Therefore,
2. Satisfy yourself whether the cirrus or cirro-stratus increases in density and tends to the formation, or induction, of stratus; and whether it is isolated, or an extension of the condensation of a storm, and if the latter,where that storm is. The time will come when an intelligent use of the telegraph will do this for you.
3. Look also to the character of the wind, if there be any. On this subject I have perhaps said allthat is necessary in the preceding pages. Next to condensation, the direction and character of the wind is the most valuable prognostic. Indeed it often tells us that a storm is approaching, and the quarter from which it will come, and its character, before the condensation is visible.
4. See if there is anysecondarycondensation or scud. These are sometimes seen running toward a storm, when there are not distinct clouds visible in the western horizon, at nightfall, or in the evening, as in the instance stated in the introduction, and sometimes from the north-east, as in cases heretofore so often stated. But the easterly scud do not often form in winter, until after the cirrus has passed into the form of cirro-stratus, or has induced the latter forms in the inferior portion of the trade, or the surface atmosphere.
The inductive effect of the primary condensation, therefore, is not always, and especially in winter, sufficient to create the easterly current and scud, and it is often the case that the easterly wind is not felt, or the scud seen, in snow-storms, until the snow has begun to fall, and the first snow will fall with a S. W. air, as I have heretofore stated. But when the condensation has so far advanced toward stratus that the easterly wind and scud are obvious, there is little or no doubt that rain or snow will fall speedily. The occasional occurrence of easterly wind and scud, without rain, however—dry north-easters, as I have termed them—in connection with storms passing south of us, or condensation too feeble to precipitate,should be remembered. The long, dry, north-easterly winds of spring have been attributed to the icebergs, but they are overlaid by feeble stratus or cirro-stratus condensation, or are the result of attraction, by a more southern precipitation. The observer must be careful to distinguish between the various forms of N. W. scud and cirro-stratus, which they sometimes resemble. This he may dofrom the direction in which they move. Cirro-stratus always moves from some point between S. S. W. and W. S. W. to some point between N. N. E. and E. N. E. The various forms of N. W. scud move to the S. E. The March, foggy scud, from between W. and N. W., rarely have any cirro-stratus above them, but rather a peculiar turbid condensation.
The character of the primary condensation, the direction and force of the wind, and the direction of the secondary condensation or scud, must be the main reliance of the observer. But I must reiterate that they all differ in different kinds of storms, in different seasons of the same year, and the same seasons of different years; and the observer must be careful to make due allowance for those differences.
There are, however, divers other secondary signs, which, although not alone to be relied upon, will aid the observer, if carefully studied, when the character of the clouds, and the pressure of easterly or southerly wind and scud, are not decisive. Of these, a large class are electrical.
The smoke descends the adjoining chimney-flues, or outside of the chimney, toward the ground.
Thus, Darwin, as quoted by Hone:
“The smoke from chimneys right ascends,Then,spreading, back to earth it bends.”
Smoke is electrifiedpositively, by the act of combustion; the earth and the adjacent atmosphere, when storms are gathering or approaching, isnegative. Hence the smoke spreads, and is attracted downward by an opposite electricity. On the other hand, it is interesting to see, at other times, and when the difference in temperature is not material, but the whole atmosphere is positive, with what rapidity and compactness the smoke will ascend in astraight and elevated columnfrom the chimney, repelled by a similar electricity. I am aware it is generally supposed the smoke descends because theair is lighter. But it is a mistake. I have seen it descend when the barometer was at 30°.60, or .60 above the mean.
There is, too, a draught downward in chimneys, in such cases when there is no smoke or fire in any of its flues. Thus Jenner says: “The soot falls down;” whether he meant by this that there was an actual fall of soot other than what is occasioned by the rain falling in through the chimney top, and disturbing the soot, as sometimes happens, I do not know. It occurs rarely, and is of very little practical importance. But every housewife knows that chimneys, which have been used in winter, and are full of soot,smellbefore storms. The odor results from a downward draught and the dampness of the air. So the smoke from one flue will descendanother, into some unused room, on such occasions. Another class of these electrical signs are felt by those who are suffering from chronic diseases, which have affected the nerves and made them sensitive. Thus Jenner:
“Old Betty’s joints are on the rack.”
And Hone adds:
“Her corns with shooting pains torment her,And to her bed untimely send her.”
But Old Betty’s rheumatism or corns are not alone in this. Those whose bones have been broken feel it. All invalids feel it. And, indeed, all observing healthy persons may, and do, although all are not distinctly conscious of it. It is common for such to say, I feel sleepy, or I feel dull, or, Itfeelslike snow, orfeelslike rain, and thus from their own feelings to be able to predict, not only falling weather, but itscharacter, whether snow or rain, at a time when either may occur consistently with appearances.
This change is a change from the positive electricity which is so congenial to the active—“bracing” is the usual term—to negative and damp—for this change is accompanied by condensation, as I believe all changes from positive to negative are. Certain it is, if the atmosphere is highly charged with negative electricity, condensation takes place; if with positive, evaporation. Perhaps it is a change of the associated electricity which accompanies magnetism, and not of the free atmospheric electricity alone. Hence another phenomenon alluded to by Jenner:
“The walls are damp, the ditches smell.”
There are localities where this dampness is very obvious. The celebrated William Cobbett, many years since, when a farmer on Long Island, observed and published the fact that the stones grew damp before a storm. I know of flagging stones that usually grow damp two or three hours before rain, especially in spring and fall, and every step taken upon them is made visible by a corresponding increase of condensation.
The reverse of this takes place just before the close of storms. Flagging stones, and walls under cover, will frequently become dry before the rain ceases. The negative electricity becomes less as the positive prevails, although the clouds above are still dropping rain.
In the comparatively moist, showery climate of England, these changes from positive to negative alternate rapidly between successive showers; but observations of electric phenomena, or of clouds, in that climate, are not, without qualification, safe guides for us.
So “the ditches smell,” particularly in the evening before a rain, when the immediate surface-atmosphere is charged with negative electricity, and thecondensing moistureprevents the diffusion of the odors. For the same reason the candle will not relight, and there is crackling in the ashes or lamp. Thus, again, Virgil:
“Maidens that nightly toil the tangled fleeceDivine the coming tempest; in the lampCracklesthe oil, the gathering wick grows dim.”
Virgil did not live in our cold climate, and knew nothing of the crackling in the fire, or in the ashes or coals which remain after the wood is consumed. The lamp exhibits it on a smaller scale, and perhaps he had noticed it when in company with the maidens. But it is sometimes noticeable even in the lamp or candle with us. A small particle of moisture will produce it, in a marked degree, at any time.
In winter, when the air is highly positive and cold, the candle can be blown out, and by another puff of the breath relighted, with ease. But when the electricity before a storm becomes negative, and partial condensation takes place, this can not be done. This partial condensation before storms and showers shows itself upon vessels containing cold-water, in summer. It seems to be the received opinion, that the condensation is evidence of a greaterquantityof moisture in the atmosphere. But this, too, is a mistake, and hence the little reliance to be placed on hygrometers.
This partial condensation is sometimes visible. When the sun shines clearly, at the east or west, through asmall openingin the clouds, the condensing vapor is shown by the streaks of sunlight, just as the fine particles of dust are seen in a dark room, when a few rays of sunlight are admitted through a small aperture. This phenomenon is often observed, and it is said of it—“It’s a going to rain;the sun is drawing water.”
Virgil alludes to this as seen in the east in the morning, thus:
“But when beneath the dawnred-fingered raysThrough the dense band of cloudsdivergingbreak,*******Ill does the leaf defend the mellowing grape;Leaps on the noisy roof the plenteous hail,Fearfully crackling.”
It is well ascertained that storm-clouds of great intensity have polarity in the different portions, and that in the less intense magneto-electrical climate of England isolated showers are often of this character—the polarity existing in rings. Showers are doubtless thus found with us. Mr. Wise got into one of them; see his description (Theory and Practice of Aeronautics page 240).
I have, in another place, alluded to the upward attraction of the dust beneath the advance condensation of a shower. Jenner alludes to it in the following lines:
“The whirling winds thedustobeys,And in the rapid eddy plays.”
So Virgil:
“Light chaff and leaflets,flitting, fill the air,And sportive feathers circle on the lake.”
All these are electrical.
In England, where the action of such isolated clouds is less intense, the different electricities in different portions of the cloud, whose opposite and changing action produce all the phenomena, the condensation, the cold and congelation, the currents, etc., have been accurately ascertained. We can not get into the situation occupied by Mr. Wise. But everyman may observe theseintestine motionsoccasionally, in the advance condensation of an isolated thunder-shower, in front of, but near the smooth line of falling rain. They are more lateral than upward or downward, and are often exceedingly rapid in movement.
I have said that hail has often been found to fall from particular and well-defined portions of a cloud, and rain from the other portions, the hail being positive, and rain negative. An instance of very striking character may be found in Espy’s Philosophy of Storms (Introduction, page xx.) Doubtless in all cases thunder-showers, which are isolated and distinct, have opposite electricity in different portions, to whose active agency all the phenomena are owing. And the return of electricity to the earth in the rain explains the greater fertilizing effect of the latter compared With all artificial watering. He was a true philosopher who attempted to stimulate vegetation by electricity.
Sounds may sometimes aid the observer in doubtful cases in foretelling the weather. The roar of the surf, or breaking of the waves on the shore, when great bodies of water are disturbed by a precedent storm-wind, often heard before the wind is perceived on the land, I have already alluded to. And thus Virgil:
“When storms are brooding—in theleeward gulfDash the swelled waves; the mighty mountains pourA harsh, dull murmur; far along the beachRolls the deep rushing roar.”
The moaning or whistling of the wind all have noticed. It is not uncommon to hear the expression, “The wind sounds like rain.” Jenner says:
“Thehollowwinds begin to blow.”
And Virgil:
“ThewhisperinggroveBetrays the gathering elemental strife.”
This whispering is the motion of the leaves; and they are often stirred by a peculiar motion which is not that of wind. Sometimes every leaf upon a tree may be seenvibratingwith anupward and downwardmotion, when there is not wind enough to stir a twig. This interesting phenomenon is electrical. Trees, and all vegetables, confessedly discharge electricity, and such discharges move the leaves, when very active.
With us, sounds can be heard more distinctly from the east or south, before storms, according to the character of the coming wind. Howard mentions an instance when he heard carriages five miles off. Steamboat paddles, rail-road cars, and other sounds, are often heard a great distance. The distance at which the now common steam-whistle is heard, and the direction, is not an unimportant auxiliary indication of the weather. Howard attributes these peculiar phenomena to the “sounding board,” made by thestratum of cloud; but sounds may be heard from the north-west, when there is no condensation, and the wind is from that quarter, and also from the eastwhen it is not cloudy; and in a level country the village bells often tell the direction of the current of air just over our heads when we do not feel it at the surface. The wind is undoubtedly moving in a rapid, and perhaps invisible current, not far above us. If from the east or south, it betokens rain; if from the western quarter, fair weather.
The conduct of the different animals furnish a considerable portion of the signs alluded to by Virgil and Jenner, and are never unimportant auxiliary evidence of the approaching changes, whether from dry to wet, or wet to dry.
The observer will find, in the conduct of our birds and animals, especially those which are not domestic, ample evidence of the truth of the descriptions of Virgil. He denies the animals and birds foresight, but he does not seem to have observed that the swallow leaves for the south as soon as theautumnalchange begins to be felt, and in August; nor the evident sagacity of othermigratorybirds. They do not act from the “varying impulse” produced by an actual state of things, but a knowledge or apprehension of those which are to come. This is nothing more or less than foresight. So foresight tends to prudence and skill, and they exercise both, and with reference to the future. The goldfinch does not build her nest in the hole of the tree, or in the crotch of the limb; buthangs itwithexquisite skillon the slenderwaving, outward branch, where no animal, or larger bird, or any depredator, can be sustained. She is not more timid than others; why does she invariably thusbuild? What makes her “impulses” differ from those of other birds, and always in thesame manner?
Jenner, too, has grouped, in admirably descriptive language, many of the peculiarities exhibited by animals and birds before approaching storms, some of which exhibit foresight, and others not.
Perhaps the rooster, who keeps ceaseless watch over his harem, is the most reliable weather-watcher we have. In my earlier days, when it was the practice to keep valuable birds of the kind much longer than it now is, and they had opportunity to becomeexperienced, it was interesting to observe how closely they watched the weather. I well remember a venerable chanticleer, who, perched on the tree among his hens, would always foretell the coming storm of the morrow, by sounding forthin the evening, andoften, his defiant note. Such note in the evening was invariable evidence of foul weather. And during the night, their earlier and more frequent crowing is often indicative of it. It is, however, in the earlier part of the day, in doubtful cases, that no inconsiderable reliance may be placed on their sagacity. Often, when a storm is gathering in the forenoon, they will announce it by an almost incessant crowing. The habits of anexperienced, old-fashioned bird, of this kind, will well repay attention; but I can not answer for the Shanghai and otherfancy breeds.
Jenner says:
“The leech disturbed, is newly risenQuite to the summit of his prison.”
Few have had, or will have, opportunities toobserve this, but it is strikingly true. It is difficult to conceive how mere condensation, from an increase of vapor in the atmosphere, should be foreseen by the leech in his watery prison. It is obvious, I think, there is an electric change which reaches him, as it does the whole animal creation, the once broken bones, and the joints of Aunt Betty. Thus much of the philosophy of signs.
The barometeris a useful instrument, in connection with observations of the other phenomena. It is especially useful to the sailor, as its indications relative to the winds are much the most certain. But it is not,alone, to be relied upon. This is well settled, although the reasons for it have not been understood. Why it should rise sometimes before storms, in opposition to the general rule—or fall at others without rain—or rise occasionally during the heaviest gales, has been a mystery, and impaired the confidence in its accuracy and usefulness even of the class of philosophers of whom Sir George Harvey spoke, in the sentence quoted in the introduction. But, as I have already intimated, it is all very intelligible.
I have said that the barometer has no fair weather standard—the mean of 30 inches at the level of the sea being anaverageof thefair weatherelevations and thefoul weatherdepressions. Its fair weather position, it would seem, must be above the mean, therefore, and as much above as its foul weather depressions are below. But this is not precisely true. Its extreme fair weather range is 31 inches, and it rarely reaches that; while its lowest storm range isdown to 28, and is the most often reached of the two. My barometer stands about 40 feet above ordinary high-water mark. It is not a “wheel,” but an open, “scale” barometer, and a perfectly good one. Its most reliable fair weather standard is about 3030⁄100inches. It is itsmost common summer, set fair position, but that position is often at other and different elevations, at other periods of the year, during fair weather. The reader must observe for his own locality, and satisfy himself what the most common set fair position for the barometer is, at the different periods of the year, where he resides. When he has ascertained this, he may apply the following principles to illustrate its exceptional action, and in judging of the future of the weather:
1st.As to its rise before storms.—Supposing it to have been stationary, at or about a set fair position,for the period, and for one or two or more days, a verygradualandmoderaterise is an indication of continued fair weather; and asuddenandconsiderable riseis indicative of a storm. If the sudden and considerable rise occurs in the latter part of spring, summer, or early autumn, it indicates a storm of thefirstorthird classesdescribed in Chapter X., if in winter, a storm of thefirst classonly. If the elevation isverysudden and considerable, the storm will probably besevere. The philosophy of this, according to my present apprehension of it, is, that these storms present anextended easterly front—settle very near the earth—andhave a rapid progress—thus accumulating the atmosphere somewhat, in advance of them.
2d.As to its fall before storms without previous rise.—This is always very regular before the second class of storms, or polar belts of showers and storms. It is very fairly exemplified in the table from Reid, on page 329. The barometer, so far as I have opportunity to observe, does not rise from a stationary position on the approach of this class of storms. At the commencement of heated, summer, dry terms, my barometer has most frequently ranged at about 30.30, and gradually, but slowly, fallen below 30 inches before the belt of showers arrived, and the term closed. The fourth rule of Dalton (Meteorology, page 183) indicates a similar law in England. It is as follows:
“In summer, after a long continuance of fair weather, with the barometer high, it generally falls gradually, and for one, two, or more days, before there is much appearance of rain. If the fall be sudden and great for the season, it will probably be followed by thunder.”
“In summer, after a long continuance of fair weather, with the barometer high, it generally falls gradually, and for one, two, or more days, before there is much appearance of rain. If the fall be sudden and great for the season, it will probably be followed by thunder.”
3d.It falls frequently and considerably without rain.—This is owing to the fact thatallregular, periodic efforts at condensation do not result in rain. The second, third, and fourth classes of storms described, may not (as we have said)be sufficiently active to precipitate, although theseries of phenomena(including the fall of the barometer) may be, in other respects, perfect. Such an instance may be found in Reid’s table, on page 329, and on the 11th of the month. But the fall in such cases is not as great, unless the wind be violent.
4th.It rises during considerable gales.—But theseare of the kind so often alluded to—viz., the N. W., in the northern hemisphere, and the S. W., in the southern; and thephilosophyof it has been explained, and is observable.
With these explanations, the reader will be able to understand, and practically apply, the barometric changes, in connection with the other phenomena, in forming an opinion of the weather.
The thermometeris also an auxiliary. Itrises, during the winter half of the year, in theadvance portion of the storm, and falls when it passes off again; and the reverse is true, as we have seen, when its range is very high in summer. It is, therefore, to some extent, a useful auxiliary, although of minor importance.
The hygrometeris of less importance still. It is not in general use as a practical guide to the changes of the weather, and does not deserve to be.
A question, which has been much mooted, deserves a passing notice in this connection—viz., whether our climate has gradually become ameliorated and milder on the eastern part of our continent, since its settlement. I have not space left for its discussion. Humboldt (Aspects of Nature, page 103) is of opinion that there has been no material change. He says:
“The statements so frequently advanced, although unsupported by measurements, that since the first European settlements in New England, Pennsylvania, and Virginia, the destruction of many forests on both sides of the Alleghanys, has rendered the climate more equable—making the winters milder and the summers cooler—are now generally discredited. No series of thermometric observations worthy of confidence extend further back, in the United States, thanseventy-eight years. We find, from the Philadelphia observations, that from 1771 to 1824, the mean annual heat has hardly risen 2°.7 Fahrenheit—an increase that may fairly be ascribed to the extension of the town, its greater population, and to the numerous steam-engines. This annual increase of temperature may also be owing to accident, for in the same period I find that there was an increase of the mean winter temperature of 2° Fahrenheit; but, with this exception, the seasons had all become somewhat warmer. Thirty-three years’ observation, at Salem, in Massachusetts, show scarcely any difference, the mean of each one oscillating within 1° of Fahrenheit, about the mean of the whole number; and the winters of Salem, instead of having been rendered more mild, as conjectured, from the eradication of the forests, have become colder, by 4° Fahrenheit, during the last thirty-three years.”
“The statements so frequently advanced, although unsupported by measurements, that since the first European settlements in New England, Pennsylvania, and Virginia, the destruction of many forests on both sides of the Alleghanys, has rendered the climate more equable—making the winters milder and the summers cooler—are now generally discredited. No series of thermometric observations worthy of confidence extend further back, in the United States, thanseventy-eight years. We find, from the Philadelphia observations, that from 1771 to 1824, the mean annual heat has hardly risen 2°.7 Fahrenheit—an increase that may fairly be ascribed to the extension of the town, its greater population, and to the numerous steam-engines. This annual increase of temperature may also be owing to accident, for in the same period I find that there was an increase of the mean winter temperature of 2° Fahrenheit; but, with this exception, the seasons had all become somewhat warmer. Thirty-three years’ observation, at Salem, in Massachusetts, show scarcely any difference, the mean of each one oscillating within 1° of Fahrenheit, about the mean of the whole number; and the winters of Salem, instead of having been rendered more mild, as conjectured, from the eradication of the forests, have become colder, by 4° Fahrenheit, during the last thirty-three years.”
The facts hereinbefore stated show that there is nothing like aregularamelioration; that the seasons differ during the same decade, and different decades. The cold decade, from 1811 to 1820, has not been reproduced. But it may be, and we know not how soon. Since that period there has certainly been a change—for even the cold period from 1835 to 1840 did not equal that from 1815 to 1820, nor indeed those of 1775 to 1780 or 1795 to 1800. But as these variations, so far as we are enabled to judge, depend upon the varying influence of the sun’s rays, and of volcanic action, it is impossible to say that equally cold periods will not return, during the latter half of this century.
If the influence of the sun was constant, and volcanic action regular, two causes would tend to modify the seasons:
1st. The exposure of the surface to a more effective action of the solar rays, by a removal of the forests, and by drainage. That such action would bemore effective upon a surface thus uncovered and drained, can not be doubted.
2d.The movement of the area of magnetic intensity, and the magnetic pole, to the west.—There is such a movement, and its progress can be measured by the increase of declination on the east of it, and its decrease on the west. And the effect of it on climate is unquestionable. In all probability it has had an influence upon ours; and a removal of that area and pole still further west—60° or 80°—would change the location of the concentrated trade, and the Gulf Stream, and restore to Greenland the fertility she once had, and which the Faroe Islands now enjoy. And, on the other hand, its removal as far east of its present position would again depopulate Greenland, and render it again inaccessible. But I can not pursue this subject.
Finally, assistance may be derived from the occasional, although imperfect, accounts of the state of the weather elsewhere, which the newspapers afford. I have been much indebted to the Associated Press of New York for intelligence contained in their telegraphic reports. Occasionally they have been very full and instructive.
On this point, however, there is less of reality in the present than of hope in the future. The time must come when the collection and dissemination of meteorological truth, will be deemed an object of national importance, and national duty. Population is increasing, by immigration and propagation, in a rapidly progressive ratio. There has been greatdanger that it would outrun agricultural production. A short crop this year would have been disastrous to our prosperity—and the danger was imminent. Every description of business, and every financial circle, felt that fever of anxiety it was so well calculated to induce. The importance of extended agricultural production, and the dependence of all classes upon its success, are now in a greater measure appreciated; and none can fail to see the value of a correct understanding of the weather to the agriculturist, how short-sighted soever they may be, in relation to its direct influence upon their own prosperity and happiness.
Our country is, physically, a most favored one. The facts disclosed or alluded to in this volume show that it is without a parallel on the face of the globe; and our facilities for meteorological observation, and the ascertainment and practical application of meteorological truth, are equally pre-eminent. The great extent and unbroken surface of the eastern portion of the continent; its excessive supply of magnetism and atmospheric currents, and the consequent marked character of the phenomena; the existence and prospective increase of telegraph lines over most of its surface; the homogeneous and energetic character of a population united, upon so large a surface, under one government; the freedom of that government from debt, and the excess of its revenue; the possession of a National Observatory, with a competent philosopher at its head; and a national institution, liberally endowed, and adapted to the collection anddiffusion of practical and scientific intelligence, give us an opportunity and a capacity for connected observation and investigation, and an ability to profit by it, that no other nation can boast.
We have, too, a just national pride. Our exploring ships have penetrated and made discoveries in both hemispheres, and our travelers have visited successfully every clime; and thus our national interests, and obligations, and pride, demand an organization, practical and permanent, in relation to this subject, and the time will come when we shall have it.
When that time comes—when the presentlimited horizonof each of us ispractically extended over the entire country—and when the actual state of the weather over every part of it is known, at the same time, to the inhabitants of every other, and every whereread in the light of a correct philosophy, prognostication will be comparatively simple and certain; andA PROGRESSwill have been made, productive of an amount of pecuniary, intellectual, and social benefit to the people, which can not be overestimated. May it come before the shadows of the night of death have gathered around us, that we may have a more perfect view of that atmospheric machinery which distinguishes our planet from others, and is, with such infinite wisdom, adapted to make it a fit habitation for man!
THE END.
Since this work was completed I have received a very valuable publication, entitled, the “Army Meteorological Register.” It is a compilation of the observations made by the officers of the medical department of the army, at the military Posts of the United States, from 1843 to 1854 inclusive, prepared under the supervision of the Surgeon-general, and published by direction of the Secretary of War. To this, there is appended a report or general review of the prominent features of American climatology, so far as the basis afforded by the published observation of the army medical Bureau would warrant positive deduction, by Mr. Lorin Blodget, a distinguished meteorologist, accompanied by temperature and rain charts, for each of the four seasons;—exhibiting the various local differences and peculiarities relative to temperature and precipitation in each.
These local differences and peculiarities and contrasts are deduced and delineated by Mr. Blodget with much ability. He was fettered, however, by the prevailing calorific theories, and the unfortunate practice of grouping thephenomenainto means for the seasons, Spring, Summer, Autumn, and Winter, which grouping is arbitrary, and comparatively uninstructive. Hence, he failed to discover what the tables and summaries most clearly disclose—the principles and system unfolded in the foregoing work.
But the summaries of this register contain observations made at posts in Western and Southwestern Texas, in Kansas and Nebraska, and in New Mexico and California, where there has been a dearth of such observations hitherto, and enable me to demonstrate, more conclusively, and I think so that none can fail to understand it, the truth of the philosophy I have endeavored to exhibit.
To do this, I will take ayear,—divide it into two seasons, the periods of northern and southern transit, the only natural and correct division—and note the phenomena in each, as each progresses.
And I will take the year 1854, because that is the last year for which the record of observation is complete; because it had marked peculiarities which are remembered; and because I have alluded to those peculiarities, and those allusions should be confirmed or disproved by the record. Unless I mistake exceedingly, the confirmation will be found signal and convincing.
I have assumed, pp. 187, 351, that the transits were greater in some seasons than others; that the drought of 1854 was owing to an extreme northern transit, or to an extension west of the concentrated counter-trade, or both, leaving us less supplied with moisture than usual.
In point of fact, it appears from these observations that it resulted frombothcauses, operatingconnectedly; and the annals of Science rarely furnish a more striking instance of analogical inference proved true by subsequent investigation.
Commencing then with the commencement of the northern transit about the 1st of February, we are enabled to trace the then location of our concentrated trade, and its subsequent progress to the north till August, and its influence upon temperature and precipitation. And we can also trace the situation during the same period, of the intervening drought, and the inter-tropical belt of rains, and the extension of the latter north over Florida and the cotton-planting States.
On the 1st of February, 1854, our counter-trade was somewhat more concentrated on its extreme winter curve, over the Southern States, than usual. Its line of excess reached up from Fort Brooke, on the peninsula of Florida, to the northwest, a little east of Pensacola on the gulf, cutting Mount Vernon Arsenal north of Pensacola, and extending thence north-westwardly on to Eastern Louisiana, and curving thence and passing N. E. or E. N. E., to the Atlantic, about the waters of the Chesapeake Bay. It thinned out to the west over New Orleans and Baton Rouge, supplying them moderately, but did not extend to the forts of Texas on the west, nor the posts in the Indian Territory at the N. W. It was east of Fort Towson, which is the south-eastern one. It did not reach St. Louis on the north, nor extend north of the Ohio River, as will appear from the tables hereinafter given. The following cut shows substantially its situation on the 1st of February.