MERCURY, THE MOON, AND VENUS
The planet Mercury probably resembles Mars in many respects, but
differs particularly in lacking an atmosphere. The fissures in the
crust of the Earth or of Mars are as a rule rapidly filled and their
contours largely hidden from sight by alluvium or sand carried by
windstorms, so that they reveal themselves only through tremors and
various emanations along their course. The fissures on Mercury on
the other hand must remain as yawning chasms. It is probable that
reducing gases stream out of these cracks as on Earth, and colour
the environment in a darker shade than the other visible part of
the planet’s surface, that is the hemisphere turned toward the Sun.
Not very volatile gases, such as sal-ammoniac, other chlorides and
sulphur, which on the Earth are deposited inside the fissures, may
here spread over large areas and discolour surrounding territory,
particularly where iron compounds are present, and, under the attack of
sulphur, turn black. Lowell has made drawings of the dark spots visible
on Mercury, one of which is reproduced as Fig. 25. These spots lie, as
on Antoniadi’s drawing of the surface of Mars (Fig. 17a), arranged in
lines which are almost straight or of a slight curvature only. This
seems to indicate that the spots belong to areas immediately adjoining
enormous fissures. According to Lowell’s drawing, these cracks are
far more regularly distributed on Mercury than on Mars. Very close to
the centre of the ever-sunny side we see a dark spot, a “lake.” It is
evident that this spot is located in by far the hottest point on the
surface of Mercury. This gives rise to the following conception. The
hottest part of Mercury was naturally the last to solidify. Mercury
evidently ceased to rotate around its own axis, leaving one side
continually exposed to the Sun, while its surface yet consisted of
lava that was fluid, at least where the sunshine was most intense. The
weakest point on the planet was therefore the one just opposite the
Sun. When later collapses occurred the cracks commenced at this weak
point. We see on the figure how not less than six fissures radiate
from this centre. Others were formed where the crust broke off from
adjacent solid portions. These latter fissures have a less rectilinear
appearance than those diverging from the centre of collapse. Along
these faults, reducing gases no doubt issue from the interior of the
planet and give a dark tone to the surface layers, which probably
consist of ferruginous dust falling from space. In the neighbourhood
of the Sun, such dust ought to be more plentiful, concentrated as it
were by the gravitation of the Sun. Mercury lies five times nearer
the Sun than the Earth does, and twelve times nearer than Mars. There
probably also exist on Mercury, as on the Moon, large mountains which
are not subject to the wear of running water and blowing sand. We
cannot, however, observe them from the Earth. Possibly they correspond
to the widely extended spots, which several investigators as Schroeter,
Vogel, and others, have noticed, formations resembling the “seas” on
the Moon. Vogel believed that he had found traces of water vapour in
the atmosphere of Mercury as in that of Mars, a belief in both cases
undoubtedly founded on erroneous observations.
[Illustration:
Fig. 25. Drawing by Lowell, representing the planet Mercury
with “canals.”
]
[Illustration:
Fig. 26. A part of the moon near its south pole. The big crater
above, in the interior and on the walls of which a large
number of smaller craters appear, is Clavius. A little
below and to the right is Longomontanus just at the edge
of the shadow; almost in the middle of the picture appears
Tycho with its central cone. The moon diameter corresponds
to 43.4 cm. Photo by Yerkes Observatory.
]
[Illustration:
Fig. 27. Mare Serenitatis (below), Mare Tranquillitatis (upper
left) and vicinity. To the left of Mare Serenitatis the
great crater Posidonius; 2.8 cm. from the right edge a
small white spot may be seen. This is the remarkable
crater Linné, said to have undergone changes. The
moon diameter corresponds to 35.7 cm. Photo by Yerkes
Observatory.
]
The part of Mercury which is turned from the Sun must be characterized
by a tremendous cold due to radiation into space. The temperature
stays probably about 200° C. (360° F.) below the freezing point of
water (328° below zero F.). Even the most concentrated solutions we
know of freeze to ice precipitating the salt considerably above this
temperature. Moisture in fluid state can, therefore, not very well
exist on this side. On the sunny hemisphere it must be lacking as well,
due to evaporation over to the cold side. As a result, the desolation
on Mercury must be far greater than that on Mars and surface changes
caused by variations in temperature are almost precluded. On account
of the so-called libration, certain dark portions near the boundary of
the illuminated hemisphere occasionally enter the sunlight. But, during
this interval, all traces of moisture are undoubtedly driven away from
these parts, also never to return.
The Earth’s moon is not entirely as stagnant as Mercury, although on
the whole it closely resembles this planet. The Moon always turns the
same side to the Earth--a small libration exists here also--so that
each part of its surface is illumined by the Sun during one half of the
synodical month (29.53 days). This time, however, is so long that the
moon’s surface in the meantime almost assumes the temperatures due to
continuous sunlight and continuous night.
Some investigators, as W. H. Pickering, are persuaded that portions
of the moon just emerged from the shadow show a lighter colour than
after a short time of illumination. These observations, however, have
not been accepted as correct. According to Pickering, the light colour
should result from a slight formation of snow or hoar-frost during the
long night of 355 hours. If an appreciable trace of vapour existed on
the Moon, it ought to evaporate and form white caps over the poles
where the Sun’s heat is not sufficiently strong to melt them. As no
such signs have ever been observed, the faith in snow on the Moon is
not likely to find many defenders.
The lunar mountains are not attacked by water or sandstorms, nor do
they peel off due to rapid heating by the Sun. They rise, therefore, to
full stature over their surroundings. Their height can be measured by
the length of their shadows. Mädler, in this manner, computed one of
the peaks of the Mountain Newton to rise 7300 m. (24,000 ft.) above the
territory on which its shadow falls. Six peaks reach between 6000 and
7000 m. (19,500 and 24,000 ft.), 21 between 5000 and 6000 m. (16,500
and 19,500 ft.), 82 between 4000 and 5000 m. (13,000 and 16,500 ft.),
and 582 reach 2000 m. (6500 ft.) and more. These figures show the
extraordinary mountainous character of the Moon’s surface compared to
that of the Earth which is thirteen times larger.
In Fig. 26, we see a picture of the portion of the Moon most rich in
volcanoes, with the crater Tycho in the centre and Clavius above.
The numerous volcanoes are particularly characteristic of the Moon.
They vary in magnitude from a diameter of over 200 km. (125 miles),
for example the colossal Clavius with its companion craters, down to
dimensions just visible with the aid of a telescope. The largest exceed
our biggest many times in width and differ essentially from them,
inasmuch as their bottoms are flat, occasionally provided with smaller
volcanic cones--see the crater Longomontanus to the right of Tycho on
Fig. 26--and surrounded by a high (inwardly often very steep, outwardly
more sloping) wall as on Clavius, Longomontanus, and Tycho. The
largest, as for example Clavius, may be compared to a province such as
Bohemia, surrounded as it is on all sides by mountains. The elevated
ring, as well as the interior of Clavius, is adorned with numerous
large and small craters. The smallest of these resemble hemispherical
excavations in the crust of the Moon, or they may be small volcanic
cones which break through the walls. Sometimes they are strung out like
pearls along rents in the ground.
All these volcanoes have undoubtedly given passage from the interior
to the surface of the Moon for enormous volumes of gases previously
enclosed in the lunar magma. Nor is it less certain that these gases
have consisted largely of water vapour. If this had been condensed to
water, oceans and rivers would have been formed, and on the bottom
of the seas would have been deposited sediments carried down from
the mountains. Such, however, is not the case. The so-called “seas”
on the Moon are indeed on a lower level than their surroundings, but
their surface is even (see Fig. 27 with Mare Serenitatis below and
Mare Tranquillitatis above to the left; see also Fig. 29 with Mare
Imbrium below; it is bounded on the right by the “Carpathians”). The
“seas” consist of volcanic rocks, and are not at all covered with loose
sediments which if present ought to reflect light better than the
volcanic vitreous rocks. But the lunar “seas” are much darker than the
environments. This shows that seas proper, or bodies of water, have
probably never existed on the Moon. Even before the surface had changed
from its molten condition the water vapour had departed from the
atmosphere, and the new quantities which the volcanoes emitted from the
depths below disappeared so rapidly that lakes were never formed. The
history of other atmospheric gases on the Moon was no doubt similar.
All evidence, therefore, points to the conclusion that life never
inhabited its rough surface. Fig. 27 shows that the “sea-bottoms” are
not free from volcanoes. They also abound in folds, corresponding to
mountain-chains on the Earth. These folds indicate old breaks in the
crust while it was yet very thin. To the right, in Mare Serenitatis,
appear a few white spots which W. H. Pickering ascribed to snow. The
largest is the much discussed “crater” (?) Linné. Mare Serenitatis is
surrounded by a ring of volcanoes.
A noted astronomer, Cerulli, observed, when he directed a glass of
moderate power, such as opera glasses, toward the Moon that the spots
seemingly arranged themselves in rows forming intersecting lines
similar to the canal-system on Mars. As the regularity disappeared
with greater enlargement, Cerulli believed that the canal-system on
Mars also would dissolve into small spots if a sufficiently powerful
telescope were used. His idea, which partly has been verified, was more
recently adopted by the Englishman, Maunder, who denies the existence
of canals on Mars. Photography, however, has proved their reality (Fig.
18).
If we disregard the illusory reticulation, there are nevertheless
on the surface of the Moon numerous designs of a nearly rectilinear
outline. There are to begin with the sinuses, extended trenches,
often dotted along their sides with minor volcanoes. Fig. 27 shows,
in the upper right corner, two such sinuses, the right one with a
small volcano, Hyginus, in the middle. There are, further, five
such volcanoes in its left arm, not visible on the photograph, and
two in the right arm. The second, “Sinus Ariadaeus,” commences to
the left with the Volcano Ariadaeus, not visible on the figure. The
explanation of the origin of these sinuses is probably to be found in
the different contraction of the Moon’s surface layer and of the hotter
substrata immediately after the solid crust was formed. In a way, they
correspond therefore to cracks in the glazing on porcelain. Like the
two sinuses just mentioned they frequently commence and end with small
craters which formed weak spots in the crust that facilitated the
original break. Later on, volcanoes broke through along the sinuses
themselves. In several regions of the Moon, and particularly in the
equatorial belt, observers have claimed discoveries of new sinuses
and occasionally of minor craters, “which could not possibly have
escaped notice if they had existed before.” At present, the almost
unanimous verdict is that such changes are very improbable, and that
the visibility of the “new” objects largely depends on favourable
sidelight, so that they might well have been overlooked if the
region in question previously was examined under less advantageous
illumination.
The most peculiar formations on the Moon are the so-called “bright
streaks” which as a rule issue in almost straight lines from some of
the larger craters, particularly Tycho and Copernicus. Those around
Tycho (see Fig. 28) do not seem to be either raised above nor depressed
below the surroundings to any degree worth mentioning. For this reason
they are not visible under oblique illumination as in Fig. 25. They
proceed in straight lines independent of elevations. This quality
is in striking conformity with the characteristics of fissures on
earth as for instance those that traverse the Tyrrhenian Sea and the
Calabrian mountains. They also resemble the canals on Mars in this
respect. Nasmyth and Carpenter caused a glass ball, containing water
under pressure, to break at one point and obtained a system of beams
radiating from this point and vividly reminding of the streaks around
the lunar craters. The same effect appears if a homogeneous plate, of
glass for instance, is broken by a blow in one point. No doubt these
streak centres were once centres of collapse although they sometimes
now are found at a considerable elevation, like Tycho. This may be
the result of a later secular lifting of the rocky substrata like the
slow rise of the Scandinavian peninsula. The streaks around Copernicus
(see Fig. 29) are very different from those around Tycho. They are not
rectilinear and consist next to the crater of distinct mountain chains
plainly visible under oblique illumination. They penetrate into Mare
Imbrium (Fig. 29 below) crossing the mighty “Carpathian” mountains.
Frequently, they are provided with minor volcanoes, as in the streak
directed almost straight downward on the figure, _i. e._, to the north.
They are obviously volcanic fissures like those on the Earth.
[Illustration:
Fig. 28. Tycho in full illumination with surrounding magnificent
system of streaks. In the lower right corner Copernicus
with a less regular system appears. Between them Mare
Nubium, in the upper right Mare Humonum, with the
great crater Gassendi below. The moon diameter
corresponds to 16.7 cm. Photo by Yerkes Observatory.
Compare Figs. 25 and 28, showing parts of the same
territory under side light.
]
The streaks, in many cases, would not be visible at all were it not
for their different colour, which is considerably lighter than that
of the surroundings. The only explanation offered for this fact is
the assumption that the original cracks were filled by some light
matter forced out from the interior of the Moon, that is by the
lunar magma. This magma was not very viscous, as it has spread out
considerably beyond the edges of the cracks proper. These presumably,
like those on Earth, were of a rather moderate width, not enough to
be distinguishable at the Moon’s distance. Similar light-flowing
emanations from long fissures are known also on our planet, for
instance, from the Laki eruption on Iceland in 1783. The colour
may be light simply by comparison with the previously solidified
crust, which, optically, as regards reflexion of light, has proved
very similar to obsidian or, even more like another volcanic mineral
product, vitrophyre. It is also possible, however, that gas bubbles
were liberated as the lava solidified and gave the surface a milkwhite
appearance--gravity on the Moon is only one sixth of that on the Earth
so that the bubbles would rise and evaporate extremely slowly from
the magma. Due to the very low atmospheric pressure on the Moon, the
bubbles would also occupy a larger volume than in a corresponding case
on Earth and become more conspicuous in proportion. They probably
partly remained on the surface of the outpoured lava as a thin scum,
which hardened in that state. Since then, it has suffered no more
change than all other formations on the Moon, while on the Earth it
would soon have been scoured away by sand and water.
[Illustration:
Fig. 29. The great lunar crater Copernicus surrounded with streaks.
Below the Carpathian mountain range and at bottom part of
Mare Imbrium. The moon diameter corresponds to 55 cm.
Photo by Yerkes Observatory.
]
Before we leave the Moon it may be well to say a few words about its
colour. Mädler states in agreement with several other observers that
Mare Serenitatis, a “sea” on the Moon’s north side (25° latitude) just
to the right of the centre meridian (see Fig. 27) is remarkable for
its beautiful pure green colour, while Mare Crisium about 16° Lat. N.
near the right edge of the Moon is of a dark grey-green hue. In Mare
Humorum (about 22° Lat. S., not far from the edge of the Moon, see Fig.
28) grey and dark green shades alternate and in Mare Frigoris, just
inside the lunar north pole, the colour is a dingy yellowish-green.
In other words, the characteristic colour of the great lava seas is
apparently green. This agrees closely with conditions on the Earth
where similar formations are coloured green by silicates of ferrous
protoxides, certain species of which are called green-stones. Franz,
however, questions the observations of Mädler and professes the belief
that very light craters appear bluish and assumes this to be a contrast
effect to the general yellow hue of the Moon. Langley investigated the
lunar radiation with the spectroscope and found that the ratio of
blue to yellow was smaller in the moonlight than in the sunlight, for
which reason the general colour of the moon resembles that of yellow
sandstone.
A very interesting observation was made at the Lowell observatory when
investigating the spectrum of the sparse light reflected from the Earth
to the portions of the Moon not exposed to the sunlight. It proved to
be of a far more blue tinge than sunlight reflected from the Moon.
Our conclusion must be that the Earth shines with a blue lustre. This
is perfectly natural, as the diffused light which reaches us after
having been scattered by particles suspended in the air (and by gas
molecules as well) is a deep blue and there exists no reason why that
part of the light which is thrown outward into space should be of a
different colour. The Earth, therefore, is blue in contradistinction
to Mars which is red, on account of its desert surface, and Venus
which is bright white. The cloudy portions around the equator and the
poles should appear light blue from without and should be separated
by dark blue bands over the so-called horse latitudes, under which the
cloudless desert regions are located on either side of the equator.
(Compare the title page illustration.)
Compared to Mars the Moon offers a scene of far greater desolation.
On Mars, we observe at least some considerable changes such as the
disappearance of the white pole-caps at midsummer when at the same time
a dark ring appears to surround them; then the “lakes” and the “canals”
come into view, beginning close to the ring mentioned, later on
nearer the equator, and finally on its other side, while the opposite
pole-cap puts on its winter hue. Again, we have the sudden appearance,
and equally hasty disappearance, of white spots, particularly in the
neighbourhood of the lakes, and the sand storms which hide the surface
of Mars and often fill its canals. The abruptness of the changes
indicate that they are confined to a very thin surface layer. The
formation, on the other hand, of canals, for many years unobserved,
must be ascribed to a volcanic activity which, while feeble, yet must
be seated in the deeper portions of the planet. In addition, a stunted
vegetation of low forms is not unthinkable in the polar regions.
As against this, the Moon is undoubtedly a stellar body entirely
insusceptible of surface change. Near its centre, it is probably not
completely solidified and an extremely slow growth of the firm crust
is therefore likely. Gases are no doubt set free during this process,
but they are unable to penetrate the enclosing thick armour and remain
therefore as bubbles in the hardening magma.
As a matter of fact, no changes have, with certainty, been detected on
the Moon’s surface. It is true that the great Wm. Herschel, known as
an excellent observer, believed that he discovered, in 1873, mountains
which had not existed before that time, and Schröter, who diligently
studied the lunar surface, was of the opinion that he too had discerned
numerous changes. These discoveries, however, were doubted by careful
critics, and after the publication of Mädler’s great work about the
Moon (1837) the complete stagnation on that body was taken for granted.
Nevertheless, there are several astronomers, such as Schmidt in Athens
(1866) and lately W. H. Pickering in Cambridge, Mass., who think that
they have discerned considerable modifications. The former held that
the crater Linné (Fig. 27) had vanished since the publication of
Mädler’s work. In 1867, Mädler, himself, proclaimed that it had the
same appearance as before. Pickering, again, reports periodic changes
of “snow” and “vegetation.” (Compare Fig. 27 taken from Pickering’s
Moon-atlas.) Closer analysis, however, indicates that the phenomena
are probably only apparent and depend on the angle of illumination at
each particular time of observation. For some time, rather more than
a quarter of a century, photography has been pressed into the service
of lunar investigation with far more objective results than would be
possible through direct ocular inspection alone. During this period,
which, it must be admitted, is not very long, no distinct signs of
changes have been recorded by the photographic plates.
The great difference between Mars and the Moon depends upon the
existence of a real atmosphere on the former. The oxygen will probably
vanish from Mars also, being used up in the course of disintegration.
But nitrogen, argon, and the other permanent gases will always remain,
as will the water vapour from the bodies of water ever present,
particularly around the south pole. It is true that this water vapour
also will diminish with sinking temperature and when the latter finally
has reached the freezing point of the salt solutions on Mars, the
canals and the lakes will cease to thaw out or liquify under the vapour
distilled over from the warm to the cold pole. But sand storms and thin
mist formations will always appear and cause colour changes on the
desolate planet.
If we wish to picture to us the future fate of our Earth when it
gradually enters the reign of darkness and cold in consequence of the
enfeebling of the Sun, we must seek our illustration on Mars and not
on the Moon. Slowly are the oceans going to freeze, finally down to
their bottom, the abundance of the rainfalls will diminish, only light
snow will now and then bring change to a surface evermore transformed
into a sand desert as far as the continents reach. Rents in the rocky
substrata of the latter will appear as dark lines, caused by the gases
rising from the interior. When the temperature at the equator has
fallen below the freezing point, the polar regions will remain the only
parts where a light covering of frost will melt in the height of the
summer season and where the last feeble organisms will eke out their
hard existence, resorting to a prolonged winter’s sleep of their seeds
and spores. Finally, the last remnant of life will also disappear and
sandstorms alone, save for the gasps of gas emanation from fissures
in the rocky ground, will bring relief to the monotonous desolation.
Falling meteoric dust, which now exists in original state only on
the bottom of the oceans, will gradually cover the entire surface of
the Earth with a mantle coloured brick-red through the influence of
atmospheric oxygen. When the oxygen itself is used up, the meteoric
dust will retain its original greyish-green hue and lend it to the
funeral pall of the Earth.
Very different conditions obtain on our neighbour planet, which is
closer both to the Sun and to ourselves, the radiant Venus, an object
of interested human attention already in ancient times. The average
temperature there is calculated to about 47° C. (116.6° F.) assuming
the sun constant to two calories per cubic centimeter (.061 cu. in.)
per minute. The humidity is probably about six times the average of
that on the Earth, or three times that in Congo where the average
temperature is 26° C. (78.8° F). The atmosphere of Venus holds about
as much water vapour 5 km. (3.1 miles) _above_ the surface as does the
atmosphere of the Earth _at_ the surface. We must therefore conclude
that everything on Venus is dripping wet. The rainstorms on the other
hand do not necessarily bring greater precipitation than with us. The
cloud-formation is enormous and dense rainclouds travel as high up as
10 km. (6.2 miles). The heat from the Sun does not attack the ground
but the dense clouds, causing a powerful external circulation of air
which carries the vapour to higher strata where it condenses into
new clouds. Thus, an effective barrier is formed against horizontal
air currents in the great expanses below. At the surface of Venus,
therefore, there exists a complete absence of wind both vertically, as
the Sun’s radiation is absorbed by the ever present clouds above, and
horizontally due to friction. Disintegration takes place with enormous
rapidity, probably about eight times as fast as on the Earth, and the
violent rains carry the products speedily downhill where they fill the
valleys and the oceans in front of all river mouths.
A very great part of the surface of Venus is no doubt covered with
swamps, corresponding to those on the Earth in which the coal deposits
were formed, except that they are about 30° C. (54° F.) warmer. No
dust is lifted high into the air to lend it a distinct colour; Only
the dazzling white reflex from the clouds reaches the outside space
and gives the planet its remarkable, brilliantly white, lustre. The
powerful air currents in the highest strata of the atmosphere equalize
the temperature difference between poles and equator almost completely
so that a uniform climate exists all over the planet analogous to
conditions on the Earth during its hottest periods.
The temperature on Venus is not so high as to prevent a luxuriant
vegetation. The constantly uniform climatic conditions which exist
everywhere result in an entire absence of adaptation to changing
exterior conditions. Only low forms of life are therefore represented,
mostly no doubt belonging to the vegetable kingdom; and the organisms
are nearly of the same kind all over the planet. The vegetative
processes are greatly accelerated by the high temperature. Therefore,
the lifetime of the organisms is probably short. Their dead bodies,
decaying rapidly, if lying in the open air, fill it with stifling
gases; if embedded in the slime carried down by the rivers, they
speedily turn into small lumps of coal, which, later, under the
pressure of new layers combined with high temperature, become particles
of graphite. Fossils proper are not formed as was also the case in the
early periods of the Earth.
The temperature at the poles of Venus is probably somewhat lower,
perhaps about 10° C. (18° F.) than the average temperature on the
planet. The organisms there should have developed into higher forms
than elsewhere, and progress and culture, if we may so express it,
will gradually spread from the poles toward the equator. Later, the
temperature will sink, the dense clouds and the gloom disperse, and
some time, perhaps not before life on the Earth has reverted to its
simpler forms or has even become extinct, a flora and a fauna will
appear, similar in kind to those that now delight our human eye, and
Venus will then indeed be the “Heavenly Queen” of Babylonian fame, not
because of her radiant lustre alone, but as the dwelling place of the
highest beings in our solar system.
The ancients believed that the fates of men could be read in the
stars and this faith persisted with the power of a religion until
a few centuries ago. It was shared by the foremost astronomers,
pre-eminently by Tycho Brahe, who endeavoured to support it through
his investigations. Traces are yet to be found in popular conceptions.
These ideas have been verified today in a certain sense although with a
wholly different meaning than held by our forefathers. The planets do
tell us the conditions that existed on the Earth at the first dawn of
life and we can also draw from them a prediction of the fate that once,
after milliards of years perhaps, will befall the latter descendants of
present generations.
In one respect the dreams of our ancestors have not proved true,
namely, with reference to the habitability of the other globes in our
solar system. According to the great Kant, conditions on the wandering
stars outside of the Earth’s orbit were so favourable to life that
their inhabitants ought to have reached a far higher development than
beings on the Earth. The last remnant of this conception lives in the
speculations about the marvellously proficient engineers who built the
magnificent system of giant canals on Mars. A thorough critique has
demonstrated that any other planet in our solar system hardly can offer
an abode for higher beings, except this very Earth, which therefore
justly may be called “the best of worlds” among those that we know. And
yet, it was undoubtedly a great truth that Giordano Bruno gave his life
for, because it is highly probable, nay almost certain, that around
the countless suns which dot the firmament spin dark bodies, although
unfortunately our most powerful lenses do not reveal them. A number
of these unseen stellar bodies shelter living beings, which even might
have climbed to a higher point on the ladder of evolution than have the
inhabitants of the Earth.
[Illustration:
Fig. 17. Map of the planet Mars in Mercator’s projection
according to drawing by Schiaparelli. A comparison
with the drawing by Antoniadi (Fig. 17a) suggests that
Schiaparelli has made a somewhat diagrammatic picture,
which sets forth a very great number of strictly straight
“canals.”
]
[Illustration: Fig. 17a. Map of the planet Mars in Mercator’s
projection, drawn in 1909 by E. M. Antoniadi.
Explanations: Meredies = south; Oriens = east; Occidens = west;
Septentrio = north; Nix = snow.
Abbreviations: M = Mare, sea; S = Sinus, bay; Fr = Fretum, channel;
L = Lacus, lake; Fl = Flumen, river;
R = Regio, region; I = Insula, island;
Pr = Promontorium, cape.
]
_A Selection from the
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Things Every One Should Know About the Sun, Moon and Stars
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A Beginner’s Star-Book
An Easy Guide to the Stars and to the Astronomical Uses of the
Opera-Glass, the Field-Glass, and the Telescope
By Kelvin McKready
_Square 8vo. Including 70 Illustrations._
_$2.75 net. Postage Additional_
This volume, peculiarly definite and helpful in method, is especially
adapted to the practical needs of those who wish a well illustrated
and clearly written handbook,--accurate in its scientific information
and yet popular enough to meet the wishes of the average man or woman.
The book is distinguished from other volumes on popular astronomy by
a novel system of mapping, and by an unusually full discussion of the
uses of the simpler astronomical instruments. Special care has been
given to reproductions of recent astronomical photographs.
“_Mr. McKready’s book is the finest thing for the beginner that I have
ever seen. It is a pleasure to read a book so excellent in so many
different ways. I have never seen photographs reproduced better. I have
never seen maps of the heavens so intelligible to the beginner, and
I have never read explanations so concise and yet so complete as in
this book._”--Prof. S. A. Mitchell, Department of Astronomy, Columbia
University, New York City.
New York G. P. Putnam’s Sons London
A Revised Edition of a Standard Work
A Field Book of the Stars
By William Tyler Olcott
Author of “Star Lore of All Ages,” etc.
_Second Edition, Revised. With Additional Material. 16^o._
_With Fifty Diagrams. $1.00 net. By mail, $1.10_
In the new edition of this standard work the author has given full
information, together with diagrams representing the result of the
latest investigations. All matters of a technical or theoretical nature
have been omitted. Only what the reader can observe with the naked eye
or with an opera-glass have been included in it.
Excellently arranged and copiously illustrated, this manual is a real
field-book and will prove valuable for all who wish to become familiar
with the stars.
New York G. P. Putnam’s Sons London
Star Lore of All Ages
A Collection of Myths, Legends, and Facts, Concerning the
Constellations of the Northern Hemisphere
By William Tyler Olcott
Author of “A Field Book of the Stars,” etc.
_8^o. With 164 Illustrations and Diagrams_
_$3.50 net. By mail, $3.75_
“A sumptuous treasure-house in which the lover of ancient myth and
modern miracle may wander for enchanted hours. Its red and gold
doors open upon a gallery of masterpieces in art, all being inspired
conceptions connected in some way with star lore. The pictures and
the legends of all ages have been ransacked to make this gallery
irresistible to art and nature lovers, and not in vain. Withal the most
intense facts of astronomical knowledge and discovery are given beside
the tapestried romance which earlier peoples wove with star-stuff as
the medium of their art. It is a book delightful to the eye, scholarly
in conception and treatment, and charming to the inner sense.”--From
_Scientific American._
“Here all the myths, legends, and facts relating to all our northern
constellations are set forth fully as well as with scientific
exactness, are illustrated with clear maps and diagrams, and are
brought into close association with their classic origins by
beautifully reproduced photographs of works of art and architecture.”
_The Outlook._
New York G. P. Putnam’s Sons London
Transcriber’s Notes
Punctuation and spelling were made consistent when a predominant
preference was found in this book; otherwise they were not changed.
Simple typographical errors were corrected; occasional unbalanced
quotation marks retained.
The spelling and accent marks of non-English words have not been
changed.
Ambiguous hyphens at the ends of lines were retained; occurrences of
inconsistent hyphenation have not been changed.
Illustrations have been moved, when necessary, to fall between
paragraphs and outside of quoted text. In some cases, this places them
on different pages than the ones given in the Table of Illustrations.
In versions of this eBook that support “links”, the page numbers in
that table link to the correct illustrations.
Wide tables on pages 113 and 146 have been split to fit within
recommended width limits. The left-hand identifier columns have been
duplicated in both halves of the split tables.
End of Project Gutenberg's The Destinies of the Stars, by Svante Arrhenius