The beautiful red sky which has been so frequent of late, morning as
well as evening, has excited much comment. The comment, however, has
consisted more of description, statement of fact, theory, and wonder as
to cause, rather than as to satisfactory explanation.
Facts in the case which would reveal the secret of this beautiful
display of nature are not complete and numerous enough at present to
establish the cause of this phenomenon on a sure basis; yet enough
facts, it would seem, have been obtained to satisfy the strong mind
capable of bridging over a wide expanse.
Facts in an argument are like piers to a bridge-the more we have of
them, c. p., the more substantial the structure. When the facts are
_legion_, the structure becomes a causeway, and there is no need of
argument.
Argument is a bridge--the fewer the facts, the more the necessity for
the bridge; the less the facts, the more argument necessary to connect
the few we have, and the more skill is required to make substantial
connecting links between the few solid piers (facts) that exist.
One of the queer things in connection with this is, the public have
looked chiefly, if not wholly, to the astronomers for an explanation
of this phenomenon, when it is not their special province to explain
matters in this department of nature.
The explanation belongs to the department of meteorology, and not to
astronomy. But the fact of having looked to the astronomers shows how
little the world knows of meteorology and how few meteorologists
there are able, ready, and willing to rise and explain in face of the
opposition of the public, who seem to think that the explanation must
necessarily belong to astronomy. Astronomy proper deals with the
position of the earth in space and its relation to the other heavenly
bodies, whether suns, fixed stars, planets, satellites, comets, or other
bodies in the vast space about us. Meteorology deals with the atmosphere
of the globe, in all its forms. Astronomy could be studied in the early
ages; its grand facts were not wholly dependent upon the advanced
condition of the mechanic arts; it could be studied even without the aid
of telescopes, though telescopes have added much to its advancement.
Meteorology, on the contrary, depended on the advancement of the arts
and sciences; they must first be perfected ere we could know much about
this branch of science. To one unfamiliar with the advancement and
perfection of meteorology within the past ten years, this statement
may seem strange, yet it is an undisputable fact that, prior to the
establishment of the daily weather reports, the knowledge on this
subject amounted to very little, and was not even worthy of being
designated a science. Prior to the advent of the weather map the world
was in absolute ignorance of the laws governing the atmosphere. Sure, we
had had large volumes on the laws of storms, but the later revelations
leave them shelved high and dry on the shores and as useless as a wreck
in a similar condition; with the daily weather map before us we have no
need to even open these huge volumes; they are completely circumvented,
and only negative in value--to show how little was known of the subject
without the full and complete facts daily collected and spread before us
on the map published by the Weather Bureau.
In order to understand the color of our sky, we must understand the
subject which is so immediately connected with it and its creation.
The earth is a sphere in space; generally speaking, it is composed of
land and water. These are two factors; the heat that it derives from
the sun forms a third factor; the three--land, water, and heat--are
essential to life, at least the higher conditions of life which
culminate in man. The old physical geography taught us this much, but
it was not able to go further and tell us why it was cold or warm
independent of the seasons; it could not explain why it was at times as
warm, and even warmer, half-way to the pole than at the equator; why it
was at times very warm in the extreme northeast while very cold in
the Southern States; cold in the northwest when it was warm in the
northeast, and warm in the northwest when cold all along the upper
Atlantic seaboard; it could not forewarn us of storms. These and a
host of other facts, which the weather map makes as plain as astronomy
demonstrates that Jupiter is a planet, the new revelation, through the
instrumentality of the perfected telegraph system, makes exceedingly
plain to us if we will but seek the easily obtained information.
The principal revelations of the weather map are the facts in regard to
the areas of high and low barometer, and the influence they exert upon
the climate of the globe.
These conditions--high and low barometer--move on general lines from the
west towards the east, or towards the rising sun, and around the world
in irregular belts. The centers of low barometer are various distances
apart, from a thousand to two thousand and even more miles apart--call
the average about two thousand miles.
The clouds are formed from the moisture present by the action of the
sun's heat. The direction of the wind is from the area of high barometer
to that of low. The nearer the winds approach the center of "low" (low
barometer), the more they partake of the lines of the volute curve, or
curve of the sea shell or water in a whirlpool. High barometer is the
atmospheric hill; low barometer is the atmospheric valley. But time at
present will not permit more than these general statements; a close
study of the weather map for a season will reveal the beautiful minor
details.
To the reader it may seem a long way round, yet in order to fully
understand the nature of the atmosphere which surrounds our globe we
must pay due attention to these newly discovered physical laws.
The red sky which was so noticeable, in the fall of 1883, the
astronomers have told us was due to "meteoric dust" which was produced
by the volcanic eruption on the island of Java, August 27, 1883.
This "meteoric dust" they say combined with the atmosphere, followed it
around the earth, and caused the beautiful redness of the sky at morning
and evening. For one, I do not believe dust of any description in the
atmosphere would produce such an effect.
There is nothing luminous, transparent, or delicate about dust. Dust
would not remain in the atmosphere for months, it would settle in a very
short time, and if thick enough in the atmosphere to obstruct the light
of the sun it would be visible, discernible, to the eye, and manifest
on the face of nature. Years ago, before the age of the weather map, we
might have thought that the atmosphere followed the surface of the earth
like the water on a grindstone, but it does not. As already seen, the
wind is from the area of high barometer to that of low, and there are
many of these "low centers."
From the best calculation we can make at present, there would be at
least some six centers on an average between the center of the United
States and the island of Java. In addition to this there would also be
a number of belts of "low" centers, which would complicate the thing
threefold at least. At all these different centers the winds would be
blowing from all points of the compass at the same time. Such winds
would not be apt to bring the "meteoric dust" from Java to the United
States, either in an easterly or westerly direction. But, it is said,
"dust" has been gathered.
How high from the surface of the ground has this _dust_ been
gathered--at what elevation?
There is undoubtedly a little dust in the air most of the time, but I do
not think that it extends very high. Where it would be the highest and
most perceptible would be on the arid plans of Africa and Asia, when
the _simoom_ is passing, or in the track of a tornado. But from the
multiplicity of these storm centers and the varied winds they would
produce even this dust could not travel from Java to America.
Again, all clouds, no matter how high or how low, are affected by the
low centers, as the movement of clouds prove, and travel from the "high"
to the "low," from and to all points of the compass. High authority
gives the heights of the clouds as follows: lower clouds, 16,000 feet;
upper clouds, 23,000 feet.
As all clouds, from the highest to the lowest, are affected by the
centers as above referred to, it follows that if this "meteoric dust"
follows the earth around, as it would have to do in order to make good
this theory, it would have to travel suspended in the atmosphere above
the upper clouds, or at a height of more than 23,000 feet, or at an
elevation of over four miles!
Now, is it reasonable to believe that dust, however fine, will remain in
the atmosphere at that elevation for over six months?
As a side argument it is suggested that the smoke of the burning woods,
or few years ago in Michigan, caused as peculiar condition of the
atmosphere. This extensive fire was on a day when the area of low
barometer was on a high line of latitude and passing to the eastward.
This naturally took the smoke, which is far lighter than dust, along
with it. It mingled with the muggy condition of an extensive "low," and
produced a yellowness of the atmosphere. This however was of only a few
hours' duration, and was only visible in favorable localities.
Here again we see the advantage of the weather maps; but for this map we
would never have been able to have satisfactorily explained the peculiar
phenomenon produced by the great Michigan fire.
If the delicate redness of the sky is not caused by dust, what is it
caused by?
But for the weather map, I think we should still be in the dark in
regard to it.
In the first place, this redness is nothing new, only the conditions
are more favorable sometimes than at others. It has always existed and
always will exist, independent of earthquakes, volcanoes, etc. Nature
is ever changing; the movements of the atmosphere more resemble the
kaleidoscope than any thing else.
The summer and fall of 1883, the movements of "high" (high barometer)
over the United States were quite central and extensive, causing this
peculiar phenomenon over a wide extent of territory.
We have no information of the condition of the barometer over the other
part of the world; we speak move particularly of the United States; yet
if certain conditions produce certain effects here, it is quite safe to
say that the same effects are produced by the same cause elsewhere.
As now well established by the map, the surface wind is from the area
of high barometer to that of low--from the atmospheric hill to the
atmospheric valley.
The tendency of this is to free "high" of all clouds and moisture; but
then it is impossible to free "high" entirely of moisture; a little
will remain, and it is just this little, which is highly rarefied, that
produces the result. We look around us and above, we see little or no
evidence of evaporation, yet it is the while going on. When the sun is
immediately below the horizon, where it will shine horizontally through
the mass of light, suspended moisture, the delicate presence of vapor
heretofore unnoticed is revealed. The action of the sun's rays is the
same as when illuminating a well formed cloud--it is an embodiment
of the same principle, but the material is much more expanded. The
particles of suspended moisture are very fine, few and far between,
therefore the effect of the light upon it is more diffused and
transparent. It is much like looking through a piece of window glass
flatwise and endwise; flatwise we do not perceive any color; endwise,
from seeing through a greater mass, the glass has a very perceptible
green color.
We see the same idea also in the rising and setting sun and moon. On
a clear, cloudless night, when nothing seems to interfere with the
brightness of the stars, we cannot, by looking upward, perceive any
moisture present in the atmosphere; but if we cast our eyes to the
horizon, whereby we see through the mass of atmosphere endwise, as it
were, and note the appearance of the stars there, or the rising or
setting moon, we will see that the atmosphere there gives a redness
to the rising body, which it does not have when it has ascended to
mid-heaven. On a clear night, which is caused by the presence of the
area of high barometer, the moon when in mid-heaven is of a clear,
silver-white, and it is the same moon that at the horizon was a deep
red. The color of the moon has not changed; it is simply the medium
through which it is seen that produces the difference in color.
Occasionally, on a clear, bright ("high") night, when the moon is full,
prior to rising, when just below the horizon, it will so illuminate this
lower strata of atmosphere as to appear like a great fire; the moon
rises red, but its deep color gradually fades as it rises, and when well
up in the heavens we perceive that this deep coloring was an illusion
and merely the influence of its surroundings. I never, though, knew of
any one to attempt to account for this by "meteoric dust;" and yet it is
an embodiment of the same principle. Place the sun where the moon is,
and from its far superior abundance of light we have a much grander
display.
Under no other conditions or relations of the sun and earth is it
possible to have this phenomenon of the delicate red sky but when a
positive area of high barometer is passing and extends over us. In
order to produce this effect we must have the clear atmosphere of high
barometer, when there is a minimum of moisture present. The action of
the sun's rays upon this extensive area of slightly moist rarefied
air is unconfined by clouds, and reaches far and wide, and produces
a delicacy of color which from no other source or condition can be
realized.