The reader who has attentively perused and considered the facts stated,
and the principles deduced, in the preceding pages, and is ready to make a
practical application of them by careful observation, will have little
difficulty in understanding the varied atmospheric conditions; and will
soon be able to form a correct judgment of the immediate future of the
weather, so far as his limited horizon will permit.
But there are other facts and considerations, not specifically alluded to,
which will materially aid him in his observations; and there is a degree
of philosophical truth in the proverbs and signs, which ancient popular
observation accumulated, and poetry and tradition have preserved, that
meteorologists have been slow to discover or admit, but which will be
obvious upon examination, and commend them to his attention.
The classical reader is doubtless familiar with that part of the first
Georgic of Virgil, which contains a description of the signs indicative of
atmospheric changes. Much of it is beautifully poetic, and, if read in the
light of a correct philosophy, is equally truthful.
I copy from a creditable translation, found in the first volume of
Howard's "Climate of London":
"All that the genial year successive brings,
Showers, and the reign of heat, and freezing gales,
Appointed signs foreshow; the Sire of all
Decreed what signs the southern blast should bring,
Decreed the omens of the varying moon:
That hinds, observant of the approaching storm,
Might tend their herds more near the sheltering stall."
PROGNOSTICS.--_1st. Of Wind._
"When storms are brooding--in the leeward gulf
Dash the swell'd waves; the mighty mountains pour
A harsh, dull murmur; far along the beach
Rolls the deep rushing roar; the whispering grove
Betrays the gathering elemental strife.
Scarce will the billows spare the curved keel;
For swift from open sea the cormorants sweep,
With clamorous croak; the ocean-dwelling coot
Sports on the sand; the hern her marshy haunts
Deserting, soars the lofty clouds above;
And oft, when gales impend, the gliding star
Nightly descends athwart the spangled gloom,
And leaves its fire-wake glowing white behind.
Light chaff and leaflets flitting fill the air,
And sportive feathers circle on the lake."
_2d. Of Rain._
"But when grim Boreas thunders; when the East
And black-winged West, roll out the sonorous peal,
The teeming dikes o'erflow the wide champaign,
And seamen furl their dripping sails. The shower,
Forsooth, ne'er took the traveler unawares!
The soaring cranes descried it in the vale,
And shunn'd its coming; heifers gazed aloft,
With nostrils wide, drinking the fragrant gale;
Skimm'd the sagacious swallow round the lake,
And croaking frogs renew'd their old complaint.
Oft, too, the ant, from secret chambers, bears
Her eggs--a cherished treasure--o'er the sand,
Along the narrow track her steps have worn.
High vaults the thirsty bow; in wide array
The clamorous rooks from every pasture rise
With serried wings. The varied sea-fowl tribes,
And those that in Caeyster's meadows seek,
Amid the marshy pools, their skulking prey,
Fling the cool plenteous shower upon their wings,
Crouch to the coming wave, sail on its crest,
And idly wash their purity of plume.
The audacious crow, with loud voice, hails the rain
A lonesome wanderer on the thirsty sand.
Maidens that nightly toil the tangled fleece,
Divine the coming tempest; in the lamp
Crackles the oil; the gathering wick grows dim."
_3d. Of Fair Weather._
"Nor less, by sure prognostics, mayest thou learn
(When rain prevails), in prospect to behold
Warm suns, and cloudless heavens, around thee smile.
Brightly the stars shine forth; Cynthia no more
Glimmers obnoxious to her brother's rays;
Nor fleecy clouds float lightly through the sky.
The chosen birds of Thetis, halcyons, now
Spread not their pinions on the sun-bright shore;
Nor swine the bands unloose, and toss the straw.
The clouds, descending, settle on the plain;
While owls forget to chant their evening song,
But watch the sunset from the topmost ridge.
The merlin swims the liquid sky, sublime,
While for the purple lock the lark atones:
Where she, with light wing, cleaves the yielding air,
Her shrieking fell pursuer follows fierce--
The dreaded merlin; where the merlin soars,
_Her_ fugitive swift pinion cleaves the air.
And now, from throat compressed, the rook emits,
Treble or fourfold, his clear, piercing cry;
While oft amid their high and leafy roosts,
Bursts the responsive note from all the clan,
Thrill'd with unwonted rapture--oh! 'tis sweet,
When bright'ning hours allow, to seek again
Their tiny offspring, and their dulcet homes.
Yet deem I not, that heaven on them bestows
Foresight, or mind above their lowly fate;
But rather when the changeful climate veers,
Obsequious to the humor of the sky;
When the damp South condenses what was rare,
The dense relaxing--or the stringent North
Rolls back the genial showers, and rules in turn,
The varying impulse fluctuates in their breast:
Hence the full concert in the sprightly mead--
The bounding flock--the rook's exulting cry."
_4th. The Moon's Aspects, etc._
"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 night
Will ne'er beguile thee with insidious calm.
When Luna first her scatter'd fires recalls,
If with blunt horns she holds the dusky air,
Seamen and swains predict th' abundant shower.
If rosy blushes tinge her maiden cheek,
Wind will arise: the golden Phoebe still
Glows with the wind. 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;
And grateful mariners redeem their vows
To Glaucus, Inoeus, or the Nereid nymph."
_5th. The Sun's Aspects, etc._
"The sun, too, rising, and at that still hour,
When sinks his tranquil beauty in the main,
Will give thee tokens; certain tokens all,
Both those that morning brings, and balmy eve.
When cloudy storms deform the rising orb,
Or streaks of vapor in the midst bisect,
Beware of showers, for then the blasting South
(Foe to the groves, to harvests, and the flock),
Urges, with turbid pressure, from above.
But when, beneath the dawn, red-fingered rays
Through the dense band of clouds diverging, break,
When springs Aurora, pale, from saffron couch,
Ill does the leaf defend the mellowing grape;
Leaps on the noisy roof the plenteous hail,
Fearfully crackling. Nor forget to note,
When Sol departs, his mighty day-task done,
How varied hues oft wander on his brow;
Azure betokens rain: the fiery tint
Is Eurus's herald; if the ruddy blaze
Be dimm'd with spots, then all will wildly rage
With squalls and driving showers: on that fell night,
None shall persuade me on the deep to urge
My perilous course, or quit the sheltering pier.
But if, when day returns, or when retires,
Bright is the orb, then fear no coming rain:
Clear northern airs will fan the quiv'ring grove.
Lastly, the sun will teach th' observant eye
What vesper's hour shall bring; what clearing wind
Shall waft the clouds slow floating--what the South
Broods in his humid breast. Who dare belie
The constant sun?"
I copy also the following from Howard:
"Dr. Jenner's signs of rain--an excuse for not accepting the
invitation of a friend to make a _country_ excursion.
"The hollow winds begin to blow,
The clouds look black, the glass is low,
The soot falls down, the spaniels sleep,
And spiders from their cobwebs creep.
Last night the sun went pale to bed,
The moon in halos hid her head,
The boding shepherd heaves a sigh,
For see! a rainbow spans the sky.
The walls are damp, the ditches smell;
Closed is the pink-eyed pimpernel.
Hark! how the chairs and tables crack;
Old Betty's joints are on the rack.
Loud quack the ducks, the peacocks cry;
The distant hills are looking nigh.
How restless are the snorting swine!--
The busy flies disturb the kine.
Low o'er the grass the swallow wings;
The cricket, too, how loud it sings!
Puss, on the hearth, with velvet paws,
Sits smoothing o'er her whisker'd jaws.
Through the clear stream the fishes rise
And nimbly catch the incautious flies;
The sheep were seen, at early light,
Cropping the meads with eager bite.
Though _June_, the air is cold and chill;
The mellow blackbird's voice is still;
The glow-worms, numerous and bright,
Illumed the dewy dell last night;
At dusk the squalid toad was seen,
Hopping, crawling, o'er the green.
The frog has lost his yellow vest,
And in a dingy suit is dress'd.
The leech, disturbed, is newly risen
Quite to the summit of his prison.
The whirling wind the dust obey
And in the rapid eddy plays.
My dog, so altered in his taste,
Quits mutton-bones, on grass to feast;
And see yon rooks, how odd their flight!
They imitate the gliding kite:
Or seem precipitate to fall,
As if they felt the piercing ball.
'Twill surely rain; I see, with sorrow,
Our jaunt must be put off to-morrow."
Howard attributes the foregoing to Jenner; but Hone, in his "Every-Day
Book," attributes it to Darwin, and gives it, with several couplets, not
found in that attributed to Jenner. These I add from Hone, as follows:
"Her corns with shooting pains torment her--
And to her bed untimely send her."
That couplet is included by Hone with what is said of Aunt Betty.
"The smoke from chimneys right ascends,
Then spreading back to earth it bends.
The wind unsteady veers around;
Or, settling in the south is found."
Those are as philosophically accurate and valuable as any.
"The tender colts on back do lie;
Nor heed the traveler passing by.
In fiery red the sun doth rise,
Then wades through clouds to mount the skies."
The first of those couplets is untrue. It is doubtless alluded to as one
of the acts of the animal creation, indicating sleepiness and inaction,
which precede storms; but colts do not lie on the back. The other couplet
is both true and important. This collection entire, whether written by
Darwin or Jenner, contains most of the signs which have been preserved,
and which are of much practical importance in our climate.
It is unquestionably true that "appointed signs foreshow the weather," to
a great extent, every where, but with more certainty in the climate in
which Virgil wrote than in our variable and excessive one. "Showers" and
"freezing gales" we can, perhaps, as well understand; but the "_reign of
heat_," by which he probably meant the dry period, when the southern edge
of the extra-tropical belt of rains is carried up to the north of them, we
do not experience. Something like it we did indeed have, during the
excessive northern transit, in the summer of 1854; but it was an
exception, not the rule.
Some of the most important of those signs from Virgil and Jenner I propose
to allude to in detail; but it is necessary to look; in the first place,
to the character of the season and the month.
We have seen that the years differ during different periods of the same
decade. That they incline to be hot and irregular during the early part of
it, and cool, regular, and productive during the latter portion--subject,
however, to occasional exceptions. The latter half of the third decade of
this century (1826 to 1830, inclusive) was comparatively warm; and, in the
latitude of 41 deg., was very unhealthy, and so continued during the early
part of the next, over the hemisphere, embracing the _cholera seasons_.
The spots upon the sun were much less numerous than usual, during the
latter half of the third decade. Thus the spots from
1826 to 1830, inclusive, were 873
1836 to 1840 " " 1201
1846 to 1850 " " 1168
and the size of those from 1836 to 1840 exceeded those of the other
years.
The attentive observer will very soon be satisfied that the seasons have a
character; and those of every year differ in a greater or less degree from
those of other years in the same decade, and those of one decade not
unfrequently from those of some other. _Periodicity_ is stamped upon all
of them, and upon all resulting consequences. Like seasons come round,
and, like productiveness or unproductiveness, healthy or epidemic
diatheses, attend them. We have seen that, in relation to mean
temperature, there are such periodical diversities, but they are more
strongly marked in the character of storms, and other successions of
phenomena. "_All signs fail in a drouth_," for then all attempts at
condensation are partial, imperfect, and ineffectual. "_It rains very
easy_," it is said, at other times, and so it seems to do, and with
comparatively little condensation. In the one case, no great reliance can
be placed upon indications which are entirely reliable in the other. So
"_all our storms clear off cold_," or, "_all our storms clear off warm_,"
are equally common expressions--as the _prevailing classes_ of storms give
a _character_ to the _seasons_. It "_rains every Sunday now_," is
sometimes said, and is often peculiarly true--the storm waves having just
then a weekly or semi-weekly period, and one falls upon Sunday for several
successive weeks; and when it is so, _that_ coincidence is sure to be
noticed and commented upon, and the other perhaps disregarded.
If the seasons depended upon the northward and southward journey of the
sun alone, entire regularity might be expected--for we have no reason to
believe that magnetism and electricity contain, within themselves,
inherently, any tendency to irregularity, or periodicity; and, the sun
being constant in his _periods_, would be constant in his _influence_. But
he is inconstant and variable in his influence, and it is apparently
traceable to the existence of spots; but I am not quite sure that it is
occasioned by the _observable_ spots alone. Grant that the intensity and
power of his rays differ on the same day, in different years, and that
difference may be attributable in part to causes which our telescopes can
not discover.
But the differences in the seasons do not depend on the variability of the
sun's influence alone. This appears from the frequent meridional and
latitudinal diversities and contrasts, to which allusion has been made.
The sun can not be supposed to exert a _less_ influence on a middle, than
a more northern latitude; nor on one series of meridians, than another.
There must, therefore, be another local and powerful disturbing cause,
varying the magnetic and electric activity and influence upon the trades,
as well in their incipiency as in their circuits, and thus controlling the
atmospheric conditions locally and in _the opposite hemispheres_. That
other disturbing cause is _volcanic action_. We can conceive of none
other, and we can detect and trace the influence of that to a considerable
extent. Unfortunately we know, and can practically know, comparatively
little of it. It has been busy with the earth since the creation, and will
continue to be so till, possibly, by a collision, it shall burst into
asteroids--its molten interior flowing out in seeming combustion--each
fragment retaining its magnetic polarities entire, and continuing on in an
independent orbit in the heavens, an asteroid, or meteorite.
While, therefore, the agency of magnetism in itself may be regular, and
the transit of the sun is regular, and "seed-time and harvest shall not
cease," yet the sun is not regular in his influence, and the magnetic
agency is disturbed by another and irregular power. And, although we can
trace the influence of both upon the seasons, we can not measure that
influence, and from it reliably foretell the weather. The discoveries of
Swabe, and future ones, relative to solar irregularities, will assist us,
but, till we understand better, and to some extent anticipate, the
changes of volcanic action, we shall not be able to understand or foresee
all the differences in the seasons. That time may come; for progress is
yet to be read in the front of meteorology, and simultaneous practical
observations made and interchanged at every important point on the globe.
Nevertheless, the seasons have a character--often a regular one--one class
of storms prevailing over all others--one series of phenomena occurring to
the exclusion of others--and we must regard it if we would arrive at
intelligent estimates of their future condition.
The most difficult part to understand are the meridional contrasts. Last
year we had one of the worst drouths which has occurred since the
settlement of the country. But while all the eastern portion of the United
States was dry, New Mexico was unusually wet; and the North-western
States, on the same curving line of the counter-trade, were not affected
by the drouth.
Extract from a letter written by Governor Merriweather, to Mr. Bennett, in
answer to a circular, published in the "New York Herald," and dated
"SANTA FE, NEW MEXICO, Oct. 25th, 1854.
"More rain has fallen during the last six months, within this
territory, than ever was known to have fallen in the same length of
time, in this usually dry climate. Generally, little or no crops have
been produced without irrigation; but this season some good crops
have been produced without any artificial watering."
We have seen that there was an apparent connection between the remarkable
volcanic action, exerted beneath the western continents during the second
decade of this century, and the remarkable coldness of that decade. And
it is easy to see that the comparative absence of volcanic action from
immediately beneath the Old World, and its presence in great excess
beneath the New, may disturb the regular action of terrestrial magnetism
above it in the earth's-crust here, and affect seasons, diatheses, and
health unfavorably; while from its absence they may be favorably affected
there. I have some general views in relation to this, but they are
necessarily speculative, for the data are few, and I reserve them.
I am, however, induced to believe that the transit of the atmospheric
machinery is greater over some portions of the northern hemisphere, in
some seasons, than others. The most natural explanation of the unusual
contrast between the drouth of the Eastern States, and the wet of the
Territories, during the last summer, is, that the concentrated
counter-trade was carried west, by some irregular magnetic action in the
South Atlantic or West Indies. But there was much evidence that the
northern extension of the atmospheric machinery was greater than usual.
The transit began _early_--it was evidently _rapid_; the rains of May fell
in April, and the spring was wet; _summer set in earlier_--all the
appearances then were unusually tropical--the polar belts of condensation
descended upon us, but they were feeble, as they doubtless become, when
they reach the tropics, and did not precipitate; the summer continued full
twenty days later--no rain falling till about the 10th of September. The
season throughout was excessive, but otherwise regular. Spring came
earlier; summer commenced earlier and continued longer; autumn held off
later, and cold weather, when it came, was uniform and severe. This season
the transit has seemed to be less than for several years.[10] The spring
was backward; the summer cool, but exceedingly regular; the autumn thus
far without extremes, and the whole year healthy and productive. It is the
normal period of the decade, between the irregular heat of the first part,
and the irregular cold of the last; and it has been normal in character,
and conformed beautifully to its location. If the transit of 1854 was
further north than the mean, as it seemed to be over this country, that of
itself would convey the showers which follow up in the western portion of
the concentrated trade, on the east of the mountains of Mexico, and cause
them to precipitate further north, over New Mexico, and thus, rather than
from a diverted trade, they may have derived their unusual supply of
moisture during the summer of 1854. On this subject I can but conjecture,
and leave to future observation a discovery of the truth.
Enough appears, however, to show the importance of taking the location of
the year in the decade, and even the character of the decade itself, into
the account.
But whatever the remote cause of the difference in the seasons, the
character of the seasons is directly influenced by the character of
storms, or periodic changes. Sometimes the tropical storms are most
numerous; at others the polar waves; and at others the irregular local
storms, or general tendency to showers. The seasons when the polar waves
are most prevalent, are the most regular, healthy, and productive. Those
where the tropical tendency is greatest, are irregular; and so are those
where the other classes predominate. These differences in the character of
the storms, are but the varying forms in which magnetic action develops
itself. I have said that there was a decided tendency to cirrus without
cumulus, in mid-winter, and cumulus without cirro-stratus or stratus, in
midsummer, and during the intermediate time an intermediate tendency. But
there is a difference between spring and autumn. Dry westerly (not N. W.)
gales prevail in March, and N. E. storms in April and May, but violent S.
E. gales are not as common. On the other hand, the dry westerly gales of
March are comparatively unknown in autumn, and the violent, tropical,
south-easters are then common.
Snow-storms occur during the northern transit, not unfrequently in April
and May; but they do not occur so near the acme of the northern transit on
its return; nor until it approaches very near its southern limit. The
quiet, warm, and genial air of April, is reproduced in the Indian summer
of autumn, but they present widely different appearances. Those, and many
other peculiarities of the seasons, deserve the attentive consideration of
every one who would become familiar with the weather and its prognostics.
These irregularities in the character of the seasons have doubtless always
existed, and always been the objects of popular observation. There are
some very old proverbs which show this. I copy a few of the many, which
may be found in Foster's collection. Mr. Graham Hutchison does not seem to
think any of those ancient proverbs worthy of notice. But he misjudges.
They are the result of popular observation, and many of them accord with
the true philosophy of the weather.
_Irregular_ seasons are unhealthy, and unreliable for productiveness. When
the southern transit was late, or limited, and the autumn ran into winter,
our ancestors feared the consequences in both particulars, and expressed
their fears, and hopes also, in proverbs. Thus,
"A green winter
Makes a fat churchyard."
There is very great truth in this proverb. Again,
"If the grass grows green in Janiveer,
It will grow the worse for it all the year."
This is emphatically true, for the season which commences irregularly will
be likely to continue to be irregular in other respects.
Another of the same tenor:
"If Janiveer Calends be summerly gay,
It will be winterly weather till Calends of May."
Janiveer is an alteration of the French name for January, and the proverb
is very old.
So March should be normally dry and windy.
This, too, they understood, and hence the strong proverb:
"A bushel of March _dust_
Is worth a king's ransom."
And another:
"March hack ham,
Come in like a lion, go out like a lamb."
So April and May should be cool and moist. It is their normal condition in
regular, healthy, and productive seasons. The grass and grain require such
conditions; and the spring rains are needed to supply the excessive summer
evaporation. This, too, they well understood. And hence the proverbs:
"A cold April the barn will fill."
"A cool May, and a windy,
Makes a full barn and a findy."
And--
"April and May are the keys of the year."
This was not very favorable, to be sure, for corn; but their consolation
was found, as we find it, in the truth of another proverb:
"Look at your corn in May, and you'll come sorrowing away;
Look again in June, and you'll come singing in another tune."
This difference in the character of the seasons occasioned the adoption of
a great variety of "Almanac days;" and they are still very much regarded.
Candlemas-day (2d of February) was one of them.
Says Hone, in his "Every-Day Book":
"Bishop Hall, in a sermon, on Candlemas-day, remarks, that 'it has
been (I say not how true) an old note, that hath been wont to be set
on this day, that if it be clear and sunshiny, it portends hard
weather to come; if cloudy and lowering, a mild and gentle season
ensuing.'"
To the same effect is one of Ray's proverbs:
"The hind had as lief see
His wife on her bier,
As that Candlemas-day
Should be pleasant and clear."
St. Paul's day, or the 25th of January, was another great "Almanac day,"
and so the verse:
"If Saint Paul's day be fair and clear,
It does betide a happy year;
But if it chance to snow or rain,
Then will be dear all kinds of grain.
If clouds or mists do dark the sky,
Great store of birds and beasts shall die;
And if the winds do fly aloft,
Then war shall vex the kingdom oft."
St. Swithin's day was another of these "Almanac days." Gay said truly,
"Let no such vulgar tales debase thy mind;
Nor Paul, nor Swithin, rule the clouds or wind."
Yet "_Almanac days_" are still in vogue to a considerable extent--such as
the _three first days_ of the year, old style--the first three of the
season--the last of the season--different days of the month--of the
lunation, etc., etc. And some still look to the breastbone of a goose, in
the fall, to judge, by its whiteness, whether there is to be much snow
during the Winter, etc.
These _Almanac days should all be abandoned_; they have no foundation in
philosophy or truth. There is one proverb, however, in relation to
Candlemas-day, which the "oldest inhabitant" will remember, and which it
may be well to retain. It has a practical application for the farmer, and
in relation to the length of the winter:
"Just half of your wood and half of your hay
Should be remaining on Candlemas-day."
The months, too, have a character which must be remembered and regarded.
_January_ is the coldest month of the year, in most localities. The
atmospheric machinery reaches its extreme southern transit, for the
season, during the month--usually about the middle. It remains stationary
a while--usually till after the 10th of February. One or more thaws,
resulting from tropical storms, occur during the month, in normal winters,
but they are of brief duration. Boreas follows close upon the retreating
storm with his icy breath. There is a remarkable uniformity in the
progress of the depression of temperature, to the extreme attained in this
month, over the entire hemisphere. It differs in degree according to
latitude and magnetic intensity; but it progresses to that degree,
whatever it may be, with as great uniformity in a southern as northern
latitude. The table, copied from Dr. Forrey, discloses the fact, and so
does the following one, taken from Mr. Blodget's valuable paper, published
in the Patent Office Report for 1853:
TABLE SHOWING THE MEAN TEMPERATURE FOR EACH MONTH AT SEVERAL PLACES, VIZ.:
+---------------------------------------------------------------------+
| | Lat. | Jan. | Feb. |March.|April.| May. |June. |
|-------------------|-------|------|------|------|------|------|------|
|Quebec, Canada E. |46 deg. 49'| 9.9 | 12.8 | 24.4 | 38.7 | 52.9 | 63.7 |
|New York, N. Y. |40 deg. 42'| 30.2 | 30.8 | 38.5 | 49.1 | 59.6 | 69.1 |
|Albany, N. Y. |42 deg. 39'| 24.5 | 24.3 | 34.8 | 47.7 | 59.8 | 68.0 |
|Rochester, N. Y. |42 deg. 45'| 26.1 | 25.8 | 33.0 | 45.8 | 56.2 | 64.5 |
|Baltimore, Md. |39 deg. 17'| 33.1 | 34.3 | 42.4 | 53.0 | 63.2 | 71.6 |
|Savannah, Ga. |32 deg. 05'| 52.6 | 54.7 | 60.0 | 68.4 | 74.8 | 79.4 |
|Key West, Fla. |24 deg. 33'| 70.0 | 70.7 | 73.8 | 76.3 | 80.2 | 82.1 |
|Mobile, Ala. |30 deg. 40'| 51.3 | 53.7 | 59.4 | 67.1 | 74.1 | 77.8 |
|New Orleans, La. |30 deg. 00'| 54.8 | 54.5 | 61.5 | 67.6 | 74.0 | 78.6 |
|Marietta, Ohio |39 deg. 25'| 32.2 | 34.1 | 42.6 | 53.0 | 61.8 | 69.2 |
|San Antonio, Tex. |29 deg. 25'| 52.7 | 57.9 | 65.5 | 69.7 | 76.4 | 80.5 |
|San Francisco, Cal.|37 deg. 48'| 50.1 | 51.0 | 53.8 | 57.7 | 55.9 | 58.8 |
+---------------------------------------------------------------------+
+-----------------------------------------+
|July. | Aug. | Sept.| Oct. | Nov. | Dec. |
|------|------|------|------|------|------|
| 66.8 | 65.5 | 56.2 | 44.1 | 31.5 | 17.3 |
| 74.9 | 73.3 | 65.9 | 54.3 | 43.5 | 33.9 |
| 72.2 | 70.3 | 61.4 | 49.2 | 39.4 | 28.3 |
| 69.7 | 67.8 | 60.1 | 47.7 | 38.2 | 28.8 |
| 76.6 | 74.5 | 67.7 | 55.8 | 45.0 | 37.8 |
| 81.3 | 80.6 | 76.9 | 67.2 | 58.3 | 52.2 |
| 83.3 | 83.5 | 82.5 | 79.1 | 75.6 | 72.8 |
| 79.8 | 79.4 | 76.1 | 65.7 | 57.0 | 52.8 |
| 80.4 | 79.6 | 77.1 | 69.1 | 57.5 | 56.2 |
| 72.7 | 70.9 | 63.5 | 51.8 | 42.6 | 34.7 |
| 82.3 | 83.3 | 79.9 | 72.2 | 62.2 | 52.1 |
| 57.9 | 62.2 | 61.6 | 61.9 | 56.2 | 50.0 |
+-----------------------------------------+
Snows during this month are much heavier, and more frequent, in some
localities than others. The reasons why this is so have been stated. The
mountainous portions of the country receive the heaviest falls. They
affect condensation somewhat, and according to their elevation. They
intercept the flakes before they melt, and retain them longer without
change. The thaws, or tropical storms, also sometimes have a current of
cold air, with snow setting under them on their northern and north-western
border. Such was the case with that investigated by Professor Loomis.
January is without other marked peculiarities. It shows, of course, those
extremes of temperature found, to a greater or less degree, in all the
months, and differs, as the others differ, in different seasons. Normally,
in temperate latitudes, it is a healthy month. The digestive organs have
recovered from that tendency to bilious diseases which characterizes the
summer extreme northern transit, and the tendency to diseases of the
respiratory organs, which characterizes the southern extreme and the
commencement of its return, is not often developed till February.
February, in its normal condition until after the 10th, and about the
middle, is much like January. Often the first ten days of February are the
coldest of the season. The average of the month is a trifle higher, in
most localities, as the tables show. This results from the increasing
warmth of the latter part of the month. There are localities, however,
where the entire month is as cold as January. Such (as will appear from
Blodget's table) are Albany and Rochester, in the State of New York, and
New Orleans, in Louisiana. At most places the difference is slight, either
way. South of the latitude of 40 deg. heavy snows are more likely to occur in
the last half of January and first half of February than earlier. About
the middle of the month we may expect thaws of more permanence in normal
seasons. They are followed, as in January, by N. W. wind and cold weather,
but it is not usually as severe. Many years since, an observing old man
said to me, "_Winter's back breaks about the middle of February_." And I
have observed that there is usually a yielding of the extreme weather
about that period. Here, again, it is interesting and instructive to look
at the tables, and see how regularly and uniformly the temperature rises
in all latitudes, at the same time; as early and as rapidly at Quebec as
at New Orleans or San Antonio; and subsequently rises with greatest
rapidity where the descent was greatest. The elevation of temperature does
not progress northwardly, a wave of heat accompanying the sun, but is a
magneto-electric change, commencing about the same time over the whole
country, and indeed over the hemisphere.
March is a peculiar month--the month of what is termed, and aptly termed,
"unsettled weather." It, may "come in like a lion," or be variable at the
outset. The northern transit is fairly started, and is progressing
rapidly, and there is great magnetic irritability. A reference to the
table of Dr. Lamont will show that the declination has increased with
great rapidity. Normally, the early part is like the latter part of
February, and the latter part approaches the milder but still changeable
weather of April. Its distinguishing feature is violent westerly wind. Not
the regular N. W. only--although that is prevalent--but a peculiar
westerly wind, ranging from W. by N. to N. W. by W., often blowing with
hurricane violence. This wind was alluded to on page 130. With the change
and active transit to the north, in February and in March, comes the
tendency to diseases of the respiratory organs--pneumonias and lung
fevers--and this is the most dangerous period of the year for aged people.
April is a milder and more agreeable month. During some period of it, in
normal seasons, and at other times in March, there is a warm, quiet,
genial, "lamb-"like _spell_, exceedingly favorable for oat seeding. When
it comes, advantage should be taken of it, for long heavy N. E. storms are
liable to occur, and frequently with snow. On the latitude of 41 deg. heavy
snow-storms are not uncommon in April. Within the last fifteen years two
such have occurred after the 10th of the month. April, as we have seen,
should be cool and moist. If dry, the early crops are endangered by a
spring drouth; if very wet, there is danger of an extreme northern
transit, and an early summer drouth. It is emphatically true that
"April and May are the keys of the year."
Its distinguishing peculiar feature is the gentle, _warm_, _trade_
rains--"_April showers_"--which, in the absence of great magnetic
irritability, that current drops upon us. There is great _mean_ magnetic
activity, but it is not so _irregularly excessive_ as in March.
May, in our climate, should be, and normally is, a wet month, and a cool
one, considering the altitude of the sun. The atmospheric machinery which
the sun moves is, however, ordinarily about six weeks behind it--the
latter reaching the tropic the 20th of June, and the former its farthest
northern extension about six weeks later. Hence it is not a cause for
alarm if May be wet and cool. The great staples, wheat, grass, and oats,
are benefited; and corn, according to the proverb, will not be seriously
retarded. The movable belt of excessive magneto-electric action, with its
tropical electric rains, so exciting to vegetation, and its periods or
terms of excessive heat, is on its way north, and sure to arrive in
season, and remain long enough to mature the corn. There have been but two
seasons in this century when corn did not mature in the latitude of 41 deg..
One during the cold decade, and the cold part of it, between 1815 and
1820; and the other, during the cold half of the fourth decade, between
1835 and 1840.
The distinguishing feature, if there be one, of May, is its long, and, for
the season, cool storms. These have, in different localities, different
names. In pastoral sections we hear of the "_sheep storms_"--those which
effect the sheep severely when newly shorn--killing them or reducing them
in flesh by their coldness and severity.
In relation to this too early shearing, there is an old English proverb,
in "Forster's Collection," viz.:
"Shear your sheep in May,
And you will shear them all away."
So there are others called "_Quaker storms_," which occur about the time
when that estimable sect hold their yearly meeting. And there are other
names given in different localities to these long spring storms. But they
are all _mere coincidences_--equinoctial and all.
Notwithstanding the storms, however, the temperature rises at a mean. The
declination is often as great as in mid-summer. The earth is growing
warmer by the increase of magneto-electric action, whatever the state of
the atmosphere. The yellow, sickly blade of corn is extending its roots
and preparing to "_jump_" when the atmosphere becomes hot, as it is sure
to do, when the machinery attains a sufficient altitude, how backward
soever it may seem to be. The farmer need not mourn over its backwardness,
unless the season is a very extraordinary one, like those of 1816 and
1836. The storms ensure his hay, wheat, and oat crops; the warming earth
is at work with the roots of his corn, and is filling with water, and
preparing for the hot and rapidly-evaporating suns of mid-summer. The
earth would grow warmer if every day was cloudy.
By the middle of June the atmospheric machinery approaches its northern
acme, the summer sets in, and not unfrequently, as extremely hot days
occur during the latter part of the month, as at any period of the
summer. But the heat is not so continuous, or great, at a mean.
From the middle of June to the latter part of August is summer in our
climate, and during that period from one to three or four terms of extreme
heat occur, continuing from one to five or six days, and possibly more,
terminating finally in a belt of showers overlaid with more or less
cirro-stratus condensation in the trade, and controlled by the S. E. polar
wave of magnetism, and followed by a cool but gentle northerly wind.
During these "heated terms," a general showery disposition sometimes,
though rarely, appears, with isolated showers, which bring no mitigation
of the heat. Not until a southern extension of them appears, followed by a
N. W. air, does the term change, so far as I have observed.
By the 20th of August, in the latitude of 42 deg., an evident change of
transit is observable, by one who watches closely, although the range of
the thermometer in the day-time may not disclose it. A greater tendency to
cirrus-formation is visible. The nights grow cooler in proportion to the
days. The swallows are departing, or have departed; the blackbirds, too,
and the boblinks, with their winter jackets on, _their plumage all changed
to the same colors_, are flocking for the same purpose, and hurrying away.
The pigeons begin to appear in flocks from the north, and the first of the
blue-winged teal and black duck are seen straggling down the rivers. At
this season, and nearly coincident with the change, the peculiar annual
catarrhs return. These are colds (so called) which at some period of the
person's life were taken about or soon after the period of change, and
have returned every year, at, or near the same period. They soon become
_habitual_, and no care or precaution will prevent them. I know one
gentleman who has had this annual cold in August for twenty-seven years,
with entire regularity; and another who has had it nineteen years; and
many others for shorter periods. I never knew one which had recurred for
two or three years that could be afterward prevented, or broken up. _Very
instructive are these annual catarrhs_ to those who think health worth
preserving, and in relation to the change of transit.
_The change is felt over the entire hemisphere._ Between the 20th of
August and the 10th of September hurricanes originate in the tropics and
pursue their curving and recurving way up over us; or long "north-easters"
commence in the interior and pass off to E. N. E. on to the Atlantic,
followed now in a more marked degree by the peculiar N. W. wind, so common
over the entire Continent in autumn and winter.
By the 10th of September the pigeons may be seen in flocks in the morning,
and just prior to the setting in of a brisk N. W. wind, hurrying away
southward with a sagacity that we scarcely appreciate, to avoid the
anticipated rigors of winter, and to be followed soon by all the migratory
feathered tribes that remain.
The nights grow cooler, although the sun shines hot in the day-time, and
woe to the person, unless with an iron constitution, who disregards the
change, and exposes himself or herself without additional protection, to
its influence. Nature has taken care of those who depend upon her, or upon
instinct, for protection. The feathers of birds and water-fowl are full;
the hair and the fur are grown. Beasts and birds have been preparing for
the change, and are ready when it begins. They know that the earth is
changing. The shifting machinery is fast carrying south that excess of
negative electricity which has so much to do with giving it its summer
heat. They feel its absence, even during the day, and the contrast between
that and the positively electrified northern atmosphere, which now follows
every retreating wave of condensation.
The musk-rat builds, of long grass and weeds, his floating nest in the
pond, that he may have a place to retire to, when the rain fills it up and
drives him from his burrow in its banks.
But man, with all his intellect, is too heedless of the change. Additional
clothing is now as necessary to him as to animals, but it is burdensome to
him in the day time, and therefore he will not wear it, how much soever it
would add to his comfort and safety during the night. He stands with his
thin summer soles upon the changed ground, or sits in a current, or in the
night air, less protected than the animals, and dysentery or fever sends
him to his long home. He has _intelligence_, but he lacks _instinct_. He
has time for the changes of dress which fashion may require, but none for
those which atmospherical changes demand. _Fashion_ has attention in
_advance_; _death_ none till _at the door_.
Now the southern line of the extra-tropical belt of rains descends upon
those who, living between the areas of magnetic intensity, have a dry
season; and the focus of precipitation in that belt descends every where.
"_Winter no come till swamps full_," the Indians told our fathers, and
there is truth in the remark; although like other general truths
respecting the weather, it is not always so in our climate. Rains fall
during the autumnal months, as during the spring months, and while the
transit of the machinery is active and the evaporation is less. And the
magnetic comparative rest, and the seed time and equable "spell" of April
is reproduced in the Indian summer of autumn.
The machinery gradually and irresistibly descends, and with an excess of
polar positive electricity, comes snow; Boreas controls, and winter sets
in, reaching its maximum of cold in January again.
Remembering, then, the differences in the normal conditions of the seasons
and months, and the different characters that the winds, and storms, and
clouds, and other phenomena bear in them respectively, let us now look at
the signs of foul or fair weather not herein before fully stated, upon
which practical reliance may be placed.
In the first place, we must look to the forming condensation. There are
many days when the atmosphere is without visible clouds, but few when it
is entirely without condensation. Such days are seen during the dry season
in the trade-wind region; and with us, in mid-summer drouths, which
partake of this tropical character; and when, at any season, but
particularly in winter, the N. W. wind in large volume has elevated the
trade very high. Condensation is not necessarily in form of visible cloud.
It may be of that smoky character which sometimes attends mid-summer
drouths, giving the sun a blood-red appearance; or it may be like that
change from deep azure to a "lighter hue," obscuring the vision, which
Humboldt describes as preceding the arrival of the inter-tropical belt of
rains. Gay-Lussac, and other aeronauts, have seen a thin cloud stratum at
the height of 20,000 to 30,000 feet, not visible at the earth, although
some degree of mistiness and obscurity were observed. At that elevation
the clouds are thin, and always white and positive. Some degree of
turbidness is frequent; it may occur, as we have stated, with N. W. wind,
but, if it does, the wind soon changes round to the southward.
This turbidness or mistiness, where it exists, and indicates rain, does
not disappear toward night, as it should do if but the daily cloudiness
which results from ordinary diurnal magnetic activity, but becomes more
obvious at nightfall; and, when hardly visible at mid-day, or during the
afternoon, may then be observed, obscuring in a degree, the sun's rays;
and, later in the evening, forming a circle round the moon. Thus Jenner--
"Last night the sun went _pale to_ bed,
The moon in _halos_ hid her head."
And so, too, Virgil--
"The sun, too, rising, and at that still hour,
When sinks his tranquil beauty in the main,
Will give thee tokens; certain tokens all,
Both those that morning brings, and balmy eve.
* * * * *
When Sol departs, his mighty day-task done,
How varied hues oft wander on his brow.
* * * * *
If the ruddy blaze
Be _dimm'd_ with _spots_, then all will wildly rage
With squalls and driving showers: on that fell night
None shall persuade me on the deep to urge
My perilous course, or quit the sheltering pier.
But if, when day returns, or when retires,
_Bright_ is the orb, then fear no coming rain:
Clear northern airs will fan the quiv'ring grove.
Lastly, the sun will teach th' observant eye
What vesper's hour shall bring; what clearing wind
Shall waft the clouds slow floating--what the South
Broods in his humid breast. Who dare belie
The constant sun?"
More frequently this kind of condensation is sufficiently dense at
night-fall to take shape, and show a bank when the sun shines horizontally
through a mass of it. I am now speaking of _storm_ condensation, or that
which indicates the approach of a storm. Thunder clouds at nightfall,
dark, dense, and isolated, are, of course, to be distinguished. Those,
every one understands to indicate a shower, and immediate succeeding fair
weather.
The halos do not, in cases of incipient storm condensation, always appear.
The moon may not be present: though, in her absence, I have seen them in
the light of the primary planets; or she may be in the eastern portion of
the heavens. When this is so, and the condensation forms slowly, there may
be less appearance of it, after the sun disappears, than before, although
a storm is approaching, and sure to be on by the middle of next day, and
perhaps with great violence. When the failure of the light no longer
reveals the denser condensation in the west, the stars may shine, as did
the sun, dimly but visibly, through the partial and invisible
condensation; and one who did not notice the bank in the west, at
nightfall and before dark, may be deceived by the seeming clearness of the
evening. Thus Virgil--
"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 night
Will 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 wind be 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, ye _can
discern_ the 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 south wind 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 gray
Are 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 a _clear 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 the _dissolving_ cloud of the
day, but the eastern, approaching portion of a _still 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 the _distinctness_ with which they may be seen, indicate the
absence or presence of condensation and its density. Virgil, alluding to
the indications of fair weather, says:
"_Brightly_ the stars shine forth; Cynthia no more
_Glimmers_ obnoxious 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 the _dissolution_ of 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 with _blunt horns_ she holds the _dusky_ air,
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, in proportion 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 decided _cirro-cumulus_ character, it is
certain to disappear. Cirro-cumulus is seen in small patches, with small,
distinct, and rounded masses, in summer, in the morning, and sometime,
during the day, after high fog has disappeared, and at other times, and is
always, when of that _distinct_ character, 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:
"If _woolly fleeces_ strew 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 morning
Is the shepherd's warning;
A rainbow at night
Is 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 from _clouds_, but falling rain, and a morning
rainbow at the west is, of course, evidence that it is _actually 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 at
_different seasons_ of the year, and in _different 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 observation and 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 the _instant 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 often _induce_ a 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 the _linear_-cirrus. The
tufted, and other fibrous forms, are seen in 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 their _offspring_ the 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 the _transverse_, 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, page 26, indicated by one bird, but the last form
is a very prevalent one in our atmosphere.
Various names have been given to different forms of _cirro-stratus_. Those
represented in Figure 5, page 26, 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 the _waves_ on the surface
of the water when the wind blows a gentle breeze. But the _wavy_ form, 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. All _wavy_ forms 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,
attenuated _lateral_ condensation, which frequently "thins out" a
considerable distance from the dense, precipitating portions of the storm.