In bulk, doth make man better be,
Or standing long, an oak, three hundred year,
To fall a log at last, dry, bald, and sear:
A lily of a day
Is fairer far in May,
Although it fall and die that night,--
It was the plant and flower of light."
The white garden-lily is a native of the Levant, but has become
thoroughly naturalised in England, and is one of the commonest but
most admired ornaments of our cottage-gardens. The old herbalists
thought highly of its medicinal properties, and pronounced it a
certain remedy for the bite of a serpent. It is true, at all events,
that its bruised petals are an excellent cure for any ordinary wound
or bruise.
Our ancestors, among their other superstitious fancies, entertained
the extraordinary belief that the price of a bushel of wheat in the
ensuing season was foretold by the number of white cups which crowned
the white lily's stem, each cup being estimated at one shilling. I
opine that our modern farmers would feel dissatisfied if the Mark
Lane averages were regulated by this simple standard.
The common Turk's-cap lily (_Lilium martagon_) is identified with
the ancient hyacinth, the "sanguine flower inscribed with woe." The
orange lily (_Lilium bulbiferum_) is a native of Southern Europe.
When the Dutch were at feud with the House of Orange, they were
accustomed to root up this flower from their gardens, as some solace
to their indignant feelings.
[Illustration: FIG. 55.--Lily of the Valley.]
* * * * *
The garden lilies belong to the natural family of the _Liliaceæ_,
which includes the following sub-orders:--
1. _Tulipeæ_, tulip tribe; bulbous plants, with the segments of the
perianth scarcely adherent in a tube.
2. _Hemerocallideæ_, day-lily tribe; bulbous plants, with a tubular
perianth.
3. _Scilleæ_, or _Alliæ_, squill or onion tribe; bulbous, with black
and brittle testa.
4. _Anthericeæ_ or _Asphodeleæ_, asphodel tribe; roots fascicled or
fibrous, leaves neither coriaceous nor permanent.
5. _Convollarieæ_, lily of the valley tribe; stem developed as a
rhizome or tuber.
6. _Asparageæ_, asparagus tribe; stem usually fully developed,
arborescent, branched in some cases, and leaves frequently permanent
and coriaceous.
7. _Alonieæ_, aloes tribe; stem usually developed, arborescent, with
succulent leaves.
8. _Aphyllantheæ_, grass-tree tribe; characterised by a rush-like
habit and membranous imbricated bracts.
THE GENTIANS.
Let me now direct your attention, reader, to a pretty plant, of very
elegant appearance: crowned, as it is, by a cluster of rosy flowers,
it would not disgrace our well-kept parterres. It is called the
common Centaury (_Erythræa centaurium_). You will never see it in the
fields side by side with the _Delphinium_; but in July and August
will meet with it frequently on the borders of woodland paths and
open glades.
Would you create for yourself by the study of nature a source
of enjoyment equally pure and inexhaustible, adopt a method of
classification for your own use, and, to facilitate you in the task,
take for your types those plants which are at once the commonest
and most characteristic of each season. Quite at your ease, you may
begin your analysis by examining the parts which, like the calyx
and the corolla, most attract your attention. The most rational
plan, however, would be, to commence with the seed, and to follow it
through all the wonderful phases of its life, from the development of
the embryo to the maturity of the fruit. Unfortunately, we are all
compelled to take time into account; time is so much more precious
than money,--it is the measurement of our existence. Undoubtedly, the
mind, with its gigantic strides, like those of an Homeric god, tends
to overleap the confines both of time and space. But the senses,
without whose co-operation the intellect could not create science,
never fail to remind us that we are, alas! but mortals. By this
incessant appeal to order, we are under the necessity of doing, not
what we _would_, but what we _can_. And the part we really play is,
consequently, much more modest than that which we love to imagine
ourselves as playing.
But to return to our flowers.
* * * * *
What see you in the little centaury which you hold in your hand?
(Fig. 56.)
In the first place, a corolla with five petals of a delicate
rose-hue, very pleasant to the sight.
Take care! those foliola are not _petals_, if you give that name
to the free parts of the corolla. Look at them thoroughly. Your
foliola are prolonged at their base in a narrow tube, which is easily
removed. If you had begun here,--if, instead of proceeding from the
top to the bottom, you had, in your analysis, proceeded from the
bottom to the top, you would have acquired a wholly different view
of things. You would have said that the corolla is tubular, greenish,
with a rosy limb, deeply divided into five lobes. And in so doing,
you would have run no risk of deceiving yourself. The indications
given by Nature herself are the most precious; they are the lessons
of a teacher who cannot err: never pass them by with indifference or
neglect. In your study of the different parts of a vegetable, follow,
as far as possible, the actual movement of the sap.
[Illustration: FIG. 56.--The Common Centaury.]
The calyx of our gentian has, like its corolla, the form of a
five-divided tube; which, indeed, is one of the usual characters of
the Gentian family.
But it is important here to take notice of this fact, because it
is not, as at first sight you would suppose, the corolla, but the
calyx, which encircles the base of the ovary. The tube of the corolla
stops towards the middle of the latter organ, and nearly on a level
with the linear divisions of the calyx. You must be careful not to
confound with these calycine divisions the green foliola which lie
around the base of the flower, and which are neither more nor less
than abortive leaves.
Now call to mind that the flower is an union of concentric whorls,
or of rings set one within another. The _staminal_ whorl and the
_carpellary_ whorl, surrounded by a double perianth (corolla and
calyx), are here composed--the first, of five stamens, and the second
of a bilobed ovary, surmounted by a twisted style. We may now
examine more closely the reproductive organs.
The stamens are inserted upon the top of the tube of the corolla,
and if you look at the base of their filaments you would be inclined
to pronounce it a foliaceous expansion, or, rather, a metamorphic
doubling of the corolla. Suppose the stamens to be the result of the
transformation of the petals, the filament would be the "claw," and
the anther the "limb" of a foliole. At least, theory would tell you
so. But observation will show that these are not petals changing into
stamens, but, on the contrary, stamens changing into petals; as is
seen in the sterile (or "double") flowers of many of our ornamental
plants, and even of some of our fruit trees. How, then, shall we
conciliate theory with observation? Look, and you shall find.
* * * * *
Observe the anthers which surmount the filaments. There is something
peculiarly characteristic in them. As they open and spread abroad
the pollen, they visibly coil themselves up in the form of a spiral.
(Fig. 58.) Owing to this twisting, they are found more or less
inclined upon their filaments, and are gifted with a considerable
mobility. Thoroughly to understand the relation between the
continuous anther and the filament, we must examine the stamens
before their expansion, while they are still folded up within the
floral bud, their matrix. The anthers are then quite straight, and,
with a magnifying-glass, you can easily see how they are inserted,
by the lower part of their back, upon the top of the filament, whose
(so-called) _connective_ prolongation separates the two lobes of
the pollen receptacle. The anthers are then _introrse_ (_introrsum_,
inwardly)--that is to say, their face being inclined inwards, they
look towards the centre of the flower, occupied by the style, a
filiform prolongation of the ovary; the apex of the style (stigma) is
thick, globulose, and of a glandular structure. The fruit, resulting
from the metamorphosis of the ovary, is an elongated fusiform
capsule, composed of two lobes, each containing a very large number
of extremely small seeds.
[Illustration: FIG. 58.--Anthers of the Centaury.]
* * * * *
The characters we have just enumerated apply, or the majority of
them, to the interesting family of the Gentianaceæ--a natural group
of plants, nearly all remarkable for their bitter, febrifugal,
and anti-scrofulous properties. The flowering cymes of the common
centaury are very frequently employed as a substitute for the
medicinal gentian, so well known as a valuable tonic.
The medicinal gentian is the _Gentiana lutea_,--a plant growing about
three feet high,--which thrives abundantly on the Pyrenees, and the
Alps of Switzerland and Austria, at an elevation of 3000 to 5000
feet. It is not, however, so common now as formerly on the Alpine
heights, owing probably to its great consumption, but it is spreading
into many districts of Central Europe.
Frequent enough in the vicinity of Paris is the _Chlora perforata_,
a gentian remarkable for its glaucous leaves and yellow terminal
flowers.
The _Gentiana kurroo_ of the Himalayas, and the British species,
_Gentiana campestris_ and _Gentiana amarella_, possess the tonic
properties of the family. The _Cheritta_ of the pharmacopœia is
the herb and root of _Agathotes chirayta_ (_Ophelia chirata_), a
herbaceous plant which flourishes in the Himalayas.
* * * * *
We must not omit a reference to a Lilliputian gentian, the _filiform
gentian_ of Linnæus, and the _Exacum filiforme_ or _Cicendia
filiformis_ of other botanical authorities.
Its stem, from two and a half to four inches in length, is
embellished with radical oblong leaves, disposed in fours, and short
caulinary leaves, opposite and linear; the corolla is yellow, the
calyx has four triangular lobes; the stamens also are four. It is
this predominant number which has induced some botanists to elevate
our little gentian into a species of _Exacum_ or _Cicendia_,--two
genera, of which the first was named by Adamson, the second by De
Candolle. As for the tiny _Gentiana pusilla_, or _Exacum pusillum_,
we may look upon it as a simple variety of the _Exacum filiforme_,
differing from the latter only in its shorter and feebler stem, in
the somewhat narrower divisions of its calyx, and the tint of its
corolla, which is of a paler yellow, sometimes inclining to rose.
Botanists, or lovers of flowers, may grow as passionately fond of
gentians as some persons do of tulips or hyacinths. But it is not
in England or Scotland, it is in the Alpine pastures of Switzerland
only, that you can hope to satisfy your _Gentianomania_.
AN ALPINE EXCURSION.
Permit me, dear reader, to set down a few hints, in case you should
at any time be disposed to make a pilgrimage into the Golden Land, or
El Dorado, of botanists and geologists.
[Illustration: FIG. 59.--An Alpine Landscape.]
Before you plunge into the Alps, you will meet, in the sub-alpine
regions, among the valleys which intersect and the meadows which
clothe the lower spurs of the Jura, the _Gentiana campestris_. It is
a plant of from five to six inches in height, whose blue, five-lobed
corolla, with its velvety gorge, changes into yellow when dried; the
two outer teeth of the calyx are elliptical, and much larger than
the others. Your attention will hardly be drawn to this tiny gentian
among the crowd of more beautiful and attractive plants blooming
around it.
One excursion which you should not fail to make is the ascent
of the Dent de Jaman,--the hieroglyphic summit of one of those
charming mountains which mirror themselves in the Lake of Geneva.
This classical, and, moreover, very easy ascent, has the advantage
of carrying you up a series of terraces, so that the character of
the vegetation changes rapidly. The acclivity begins at the little
town of Montreux, situated near the point where the blue arrowy
Rhone pours its waters into the enchanted lake. From Montreux to
the village of Glion, you will be delighted to greet your old
acquaintances: the familiar faces of your native fields, meadows, and
woodlands. But soon a difference in the character of the flora forces
itself upon you. Species which are rarer at home become tolerably
common, as, for instance, the yellow digitalis (_Digitalis lutea_),
so easily recognised by its cymes of tiny flowers. The vulneraria
(_Anthyllis vulneraria_) is as widely diffused as the trefoil in our
English pastures.
* * * * *
A little above Glion,--a picturesque village apparently hung over the
lake--the _sub-alpine region_ commences. Around villas and mansions,
nearly all inhabited by English families, you will find in abundance
the English mercury (_Chenopodium Bonus Henricus_), and in the shady
hedges the narcotic Herb-Paris (_Paris quadrifolia_).
The apparition of the _Astrantia major_, which resembles an
artificial or fancy-created flower, warns us that we are passing
beyond the limits of the ordinary flora. I believe that we have no
representative in England of that singular umbellifer. The Alpine
pastures of the narrow-ridged Mount Caü, which resembles the back
of a dromedary, exhale a fragrance like that of the famous Swiss
tea, so much extolled as a remedy against cholera. The odour of the
hay-lofts attached to the châlets--true shepherd's huts--which rise
at intervals along the back of Mont Dromedary, is so penetrating
as to produce headache. The hay owes its aromatic fragrance to the
musk-chervil (_Myrrhis odorata_), whose strong stems form such thick
luxuriant pasturages; to various orchideæ, particularly to the
_Nigritella suaveolens_, remarkable for the intense colour--nearly
black--of its flowers; and finally, to the gentians, whose scent is
strongly brought out by drying.
* * * * *
The rich close sward which borders on the Dent de Jaman provides
the herboriser with more than one agreeable surprise. You will be
struck by the beauty of the flowery tufts of the _Linaria Alpina_,
rejoicing in a deep sapphire blue. You will also have an opportunity
of making acquaintance with a campanula which is abundant on Mont
Cenis (_Campanula Cœnisia_); its beautiful terminal flower, of a
pale blue, is characterised by the long hairs which line the opening
of the corolla.
* * * * *
Among the gentians, those great ornaments of the Alpine pasturages,
we shall direct the attention of our readers to--
The purple gentian (_Gentiana purpurea_), and the spotted gentian
(_Gentiana punctata_). These are distinguished by their plentiful
appearance: their large oval leaves, and the height of their vigorous
stems, recall those of the yellow gentian. The features which
separate these two species are not very distinct: the corolla of the
former is purple without and yellow within; that of the latter is of
a bright yellow, marked by spots of deep purple, which, however, are
not permanent; the calyx is campanulated, with upright and lanceolate
foliola.
* * * * *
The _Gentiana acaulis_ contrasts singularly with the preceding
species, its stem being so short that one is almost tempted to deny
the existence of any; its large corollas, of a bright celestial blue,
lie on the ground as if they had fallen fresh from a bouquet. We must
not confound this species with the _Gentiana pumila_, a much smaller
plant, with a very elongated calyx, which grows abundantly on the
turf of Mont St Bernard.
The _Gentiana verna_ and the _Gentiana nivalis_, with a corolla of
the finest azure, inhabit the loftiest points of the Alps, where all
vegetation begins to disappear. The former, or the gentian of spring,
flowers, in these frozen regions, in June and July; it is one of
twenty-four phanerogamous plants of the last vegetable station of
Mont Blanc. This station is formed by a series of vertical layers of
protogene, which separates the upper part of the Glacier des Bossons
from that of Taconay. The débris of the rock, decomposed under the
influence of atmospheric agencies, form, in the midst of the _nevé_,
tiny flowering parterres--oases in the desert, islands in the vast
ocean of ice and snow. There, sheltered by the rocks, and warmed by
the sun, and refreshed by the snow, which rapidly melts in summer,
these pretty plants thrive and grow beautiful, though their brief
existence is summed up in a few short weeks.
According to Charles Martins, the phanerogamous plants which flourish
at an elevation of 10,000 feet are the following:--
_Mean temperature, 47° to 36°._
1. Gentiana verna.
2. Silena acaulis.
3. Draba frigida.[66]
4. Draba fladnizensis.
5. Cardamine bellidifolia.
6. Cardamine resedifolia.
7. Potentilla frigida.
8. Phyteuma hemisphericum.
9. Pyrethrum Alpinum.
10. Erigeron uniflorum.
11. Saxifraga bryoides.
12. Saxifraga Groenlandica.
13. Saxifraga muscoides.
14. Saxifraga oppositifolia.
15. Androsace Helvetica.
16. Androsace pubescens.
17. Lazula spicata.
18. Festuca Halleri.
19. Poa laxa.[67]
20. Poa cæsia.
21. Poa Alpina.
22. Trisetum subspicatum.
23. Agrostis rupestris.
24. Carex nigra (Cariceæ).
THE PIMPERNEL.
Accompany me to the corn-field; not for any discourse upon the state
and prospect of the crops, or on the comparative value to man of
wheat or barley, but for the sake of the little red flower which
shines like a star among the growing harvest.
You cannot mistake it, for, with the exception of the tiny
chaff-weed, the smallest wild plant which bears a distinct flower,
it is the only scarlet blossom in the wheat-field, except, indeed,
the red poppy, which every good farmer seeks to banish from his land.
Mark me,--I say the only _scarlet_ flower; for there are several--as,
for instance, the pheasant's eye, or Adonis--of a deep crimson.
The pimpernel belongs to the Primrose family, or Primulaceæ. It has
a five-cleft calyx, and a monopetalous corolla. Its stamens, of an
equal number, are inserted on the corolla, opposite its segments.
It is a _meteoric_ flower; so-called, because it keeps itself shut
during wet or cloudy weather. Hence, it is known among country people
as "the shepherd's warning" or "poor man's weather-glass." And
Darwin, enumerating the various signs of rain, says of it--
"Closed is the pink-eyed pimpernel;
In fiery red the sun doth rise,
Then wades through clouds to mount the skies:
'Twill surely rain, we see 't with sorrow;
No working in the fields to-morrow."
It should be added, however, that if the rain continue for several
days, the pimpernel will lose its sensibility, and cease to act as a
natural weather-glass.
And here we may observe, that singular as is the habit of the flowers
anticipating rain by folding their petals within their calices,
the way which the Siberian sow-thistle has with it is still more
curious. This plant, during that clear weather which most flowers
affect, keeps entirely shut; but as soon as a thick mist overspreads
the earth, or a cloud obscures the bright face of heaven, it begins
to open its light blue corolla.
Everybody knows, or should know, that when the robin looks sad and
drooping, and ceases to greet you with his wonted blithesome strain,
"foul weather" is at hand. Many animals, by their peculiar habits,
afford equally certain indications of approaching atmospheric changes.
This does not seem strange to us; we account for it by the instinct
which every animal possesses, in a larger or smaller degree. But the
same anticipatory faculty is possessed by several plants; they feel
the increasing moisture of the air long before it can be detected by
ourselves. Thus, when a storm is at hand, some species of anemones
fold up their blossoms; the fragrant flowers of the wild pink
convolvulus wind themselves together; the awns of the wild oat, and
the sweet-scented meadow-grass, stand in an erect position, and the
clover leaves are drawn closely up.
Naturalists, says Pratt, are unable to discover why some plants
should be affected by moisture and others not; but the regular
changes of these natural barometers seem a providential arrangement
to supply certain wants of the flowers in which they occur. We may
draw this inference from the different positions of several flowers
according to their circumstances. Thus the poppy, when in bud, hangs
down on its stem, and preserves its petals from rain and wind; but
as soon as it is fully developed, and has acquired strength, and
the sun's rays are necessary to perfect its colours, it expands to
the full light of day. The violet, again, while its seed is forming,
shades the capsule by its purple corolla; but as soon as the seeds
are ripe, and they are required to spring to some distance from
their capsules, the flower immediately rises up with the cup for
its support, and flings abroad its offering on the earth's maternal
bosom. Adaptations of this kind are frequent and striking in the
vegetable kingdom, and surely one is justified in regarding them as
the work of an all-powerful and all-wise Creative Mind. Look, for
instance, at the orchis: it grows on the ground in Europe, and is
consequently provided with roots formed of large lobes; but when it
festoons the pillar of the virgin forests of the New World, its roots
are formed of a number of fibres, so that they may penetrate the bark
of the tree.
But to return to our pimpernel. It was at one time called
_Centunculus_, from _cento_, a covering, because it spread in
such abundance over the cultivated fields. Its botanical name was
afterwards changed to _Anagallis arvensis_. _Anagallis_ signifies
"to laugh," and there existed an old belief that a decoction of the
pimpernel acted as a remedy against melancholy, and a provocative of
mirth.
The seeds of this plant are very numerous. They are enclosed in small
capsules, and eaten by the birds.
There is only one other _British_ species of pimpernel, the
_Anagallis linetta_, or bog pimpernel, which it would be unpardonable
if the botanist omitted to notice, so delicately beautiful are
its pale-rose blossoms and tiny clusters of leaves. As its name
indicates, it is found only in marshy localities.
The blue pimpernel (_Anagallis cerulea_), though not a native of
England, is found occasionally. It is described as growing in
beautiful little tufts about the hills of Madeira, and enlivening
them by its cheerful colour, which may bear comparison with the azure
of the sky.
[Illustration: FIG. 60.--"The Wheat-field, with its mass of emerald
waves."]
And here we will take leave of the wheat-field, with its mass of
emerald waves, now beginning to wear a golden glory on their crests,
as they ripple in the genial sunshine.
ANIMALS.
_The Mole, the Staphylinus, and the Mole-Cricket._
Do you hear that noise? It seems to issue from beneath yonder heap of
pebbles at the foot of the garden-wall. Surely the stones are moving;
they seem to be walking alone, and of their own impulse, for I cannot
see anything to set them in motion.
Let us draw near and examine the mystery. "Ah, what a hideous black
creature!" It is retreating in a terrible state of alarm, as if it
felt itself pursued by some formidable enemy.
This "hideous creature" is known to French gardeners by the name of
_courtilière_; to naturalists, as a species of _Staphylinus_. (Fig.
61.) Its great and persistent adversary is the mole: a mammal at war
with an insect!
[Illustration: FIG. 61.--The _Staphylinus olens_.]
Watch well, I pray you, the mole's movements, which you can do
the more easily that here, contrary to his ordinary custom, he is
wandering in the open day; the light blinds him,--accustomed as he
is to pass his life in the subterranean galleries which he excavates
by his own labour. But if he does not see us, he hears us; the sound
of our footsteps was sufficient to make him prick up his ears (if
we may so speak of a mole), and he remains motionless. Do not stir,
or he will betake himself to flight, and we shall lose an excellent
opportunity of being present at a very curious spectacle.
He is now reassured. He recommences his manœuvres, pushing before
him every little pebble which he meets with. For this purpose
he employs his elongated snout, exactly as a pig grubs among
the uncleanness of his sty. But his next movements are not of a
porcine character. With feet broad as battledores, the mole, while
manœuvring with his nose, quietly pushes aside every clod which
threatens to obstruct his progress. These sidelong, abrupt, and
jerking movements remind you of those of a dog, seeking with his
paws to enlarge the opening of the burrow wherein a rabbit has
taken refuge. The mole has thus the habit of a hunting-dog; and, to
complete the resemblance, he stops at intervals in his scratching,
and shakes the dust off his head. One is quite surprised to see
a little mammal executing the movements we are wont to regard as
peculiar to an animal much larger than he is.
* * * * *
The beetle quits in affright the heap of stones where it had hoped to
find an asylum; it now crosses our path, holding itself erect, with a
menacing air, and its tail armed with a forked barb. The mole follows
in close pursuit: who would have believed he could run so quickly?
Let us bar his passage, and study him at our leisure.
* * * * *
The first thing we remark is his glossy hair, which is softer to the
touch than the finest velvet. Where are his eyes? Blow aside the hair
which covers his face. There they are, and they resemble miniature
pearls of a shining black.
How could Aristotle say that the mole had no eyes? To believe it
you must read the assertion for yourself. And here are the very
words of the authority who, for so many centuries, was accepted as
infallible:--
"All viviparous animals have eyes, _except the mole_" (πλὴν
ἀσπάλακος).
Then, as if a sudden doubt had seized him, and he were frightened
at his own statement, the illustrious Stagyrite hastens to add: "We
might, perhaps, strictly admit that he has." But another change comes
over the spirit of the philosopher's dream; his hesitation vanishes,
and he immediately repeats and justifies his former assertion in
these terms:--
"But, carefully considered, the mole does _not see_, because he has
no apparent eyes externally" (ὅλως μὲν γὰρ οὔθ' ὁρᾷ,
οὔτ' ἔχει εἰς τὸ φανερὸν δήλους
ὀφθαλμούς).[68]
These last words denote--I beg pardon of the manes of a great
philosopher--an absolute want of observation. Evidently, Aristotle
had not taken the trouble to _look_ before he made his statement. And
do not think that this curious indifference was peculiar to the great
master of the Peripatetic School; it characterises more or less all
the philosophers of antiquity, as well as too many who have followed
in their footsteps.
Pliny has simply translated Aristotle when he says:--"Among
quadrupeds the moles are wanting in the sense of sight" (_quadrupedum
talpis visus non est_).[69]
But it is a curious thing that both Aristotle and Pliny maintain,
that if you lift up the skin where the eyes _ought_ to be, you will
perceive the organs of vision. How could they remove the skin without
distinguishing in it the eyes, like black and brilliant beads? Did
they practise anatomy, like their own imaginary mole, without eyes?
The whole matter would be inexplicable if we did not take into
account that force of inertia which binds man in chains of iron, in
the moral world as well as in the physical.
To see, to observe; to retrace one's steps, that one may see and
observe more distinctly; is a labour repugnant to the human mind.
To create systems, in order that he may proclaim himself a great
doctrinal teacher, is the work which flatters man, or the creative
power of his imagination. Centuries of effort are needed before he
can disentangle himself from his self-woven thrall in presence of the
phenomena of nature.
* * * * *
A striking peculiarity in the mole's structure is his hands, or
feet, with their five fingers, or toes, turned outward, and their
curious resemblance to the human hand. Few animals exhibit a similar
conformation. Everything in the structure of the fore-limbs indicates
the animal's burrowing instinct,--the length of the bone, which
corresponds to the human _radius_, or fore-arm,--the breadth of the
hands,--and the bend of the arms, which are so fashioned that the
elbows project outwardly.
Does the mole's burrowing instinct lead it in quest of insects or of
vegetable roots?
According to the old traditional belief, the mole feeds upon
roots. From time immemorial, it has been looked upon as an animal
so destructive, that, in every country, its destruction has been
encouraged by large rewards. Well, this belief, transmitted from
generation to generation, owes, like so many other traditions, its
authority to its antiquity, and is devoid of foundation.
The mole is an essentially carnivorous animal, and no more lives
upon roots than the dog or the cat. He is pre-eminently the hunter
of the white-worm and beetle; and therefore, instead of vowing its
extermination, we ought to take every possible means to preserve and
multiply his race. These absurd traditions and credulous notions,
wholly without any experimental confirmation, frequently lead us to
take steps in diametrical opposition to our own interests.
Moles are particularly partial to meadows which are somewhat damp,
as, for instance, those where the leafless colchicum displays, in
autumn, its pale-rose flowers. In summer, the fields are covered
with mole-hills. It will be said, perhaps, that these conical heaps
of earth are injurious to vegetation. But that will be an error,
contradicted by observation. Meadows besprinkled with mole-hills
grow excellent hay, if care be taken to level them; for the earth
thus distributed serves as manure. If they are visited by the moles,
it is because these animals find there a plentiful supply of the
_rhizophagous_ (root-eating) insects, on which they feed.
The forest is also a favourite haunt of the moles. Apparently they
find, under the layers of leaves and roots, so rich in larvæ of
every kind, the wherewithal to satisfy amply their insectivorous
tastes. It is the mole which generally produces that rustling of
the dry leaves the wanderer is so apt to attribute to a snake or an
adder. Stand still for a moment, and patiently watch. Do you see that
undulatory movement? Thrust your stick rapidly into the uplifted
heap. There is our persevering hunter; he struggles hard to escape
from his terrible enemy, but, with a little alacrity, you will not
find it difficult to capture him.
Moles are among the most prolific of mammals; and, in fact, were it
not so, their race would have been long ago exterminated. We may,
perhaps, venture to say, that by multiplying so prodigiously, they
wish to do us a service in spite of ourselves. How tender is the
solicitude of nature for the ungrateful human species!
To see the marvellous qualities ascribed to the mole by the ancients,
one would suppose that they had made him the object of their special
study. Yet, as we have shown, they could never have watched his
habits with any degree of patience. They saw everything through the
delusive prism of their imagination. As a proof, we will tell you
what they said of the mole.
"Since this animal has been doomed to a perpetual blindness, and
lives interred beneath the surface of the earth, like the dead, he
possesses, by way of compensation, some extraordinary qualities.
His subterranean existence renders him, of all animals, the most
capable of religion (_nullum religionis capacius animal_). To acquire
the gift of second-sight, you must eat the heart of a mole, while
still beating, and freshly plucked from the animal's body. To cure
toothache, suspend to your neck the tooth of a live mole. Lymphatic
people will gain in strength if sprinkled with a mole's blood. The
ashes of a mole are a sovereign remedy for scrofula; some recommend
for this disease the animal's liver, others the right foot, and
others the head. The earth of mole-hills, fashioned into pastilles,
and preserved in a tin box, is an excellent cure for all kinds of
tumours, and especially for abscesses on the neck."[70]
Such, according to Pliny's report, are the virtues of the mole, as
taught by the Magi. The Middle Ages adopted this teaching, and even
to-day, in obscure rural districts, you will meet with superstitious
notions which remind you of the ideas of the ancient wise men and
necromancers of antiquity.
We have thus summarised the natural history of our _hunter_, let us
now say a few words respecting the _game_ he pursues.
* * * * *
The insect before us is the _Staphylinus olens_. Its study has been
much neglected, probably on account of its repulsive appearance.
But, conquering our repugnance, let us take the creature between
our forefinger and thumb. See how vigorously it defends itself! Its
forked appendage is not formidable, it is too soft; but take care of
its mandibles! With these hard, horny, pointed pincers, it pricks the
skin and draws blood. Now, bring your nose close to the frightful
black insect at the very moment when it appears the most irritated.
Come! A little courage will conquer your new feeling of disgust.
What do you smell?
A pleasant odour of rennet apples! It reminds me of that diffused
by another insect, much less ugly than your _Staphylinus_, the
_Cicondela campestris_.
It is this peculiarity which explains the specific name of
"odorous" (_olens_) given to your captive. As for its generic name,
_Staphylinus_, I have no means of interpreting its etymology; for the
insect's shape has no resemblance to that of a bunch or cluster,--in
Greek, ςταφυλή. But this last word also signifies the _uvula_, and,
perhaps, by the effort of a little imagination, the naturalist may
trace a similitude between that organ of the throat and the body of
the _Staphylinus_.
The _Staphylini_ are characterised by a very narrow neck, which
separates, as by a kind of web, the head from the thorax. In
diffusing the peculiar odour of which we have just spoken, they
simultaneously eject a musky volatile liquid contained in two
retractile whitish bladders, situated near the anus. They run
quickly, elevating their abdomen like the earwig. The antennæ,
inserted in the rear of the strong mandibles, are each composed
of eleven articulations, of which the first is the longest; these
joints, rounded in form, are arranged like the beads of a necklace.
* * * * *
The Staphylini belong to that numerous section of insects whose
_tarsi_ are composed of five articulations, and which have thence
received the name of Pentaceii.
In this section they form, with some other genera, the family of
_Brachelytræ_, so called because their elytra, or wing-sheaths, are
much shorter than the abdomen.
Our _Staphylinus olens_ is finely punctuated, somewhat hairy, and
of a dull black colour. Though very common in our gardens, and
wherever any putrefying substances are to be found, its habits
are not very well known. For if it were generally understood that
it is an essentially carnivorous animal, that it carries on a
determined warfare against the caterpillar, larvæ, and especially the
white-worm, far from seeking to destroy it, men would surely attempt
to increase its numbers. It is a proof that the Staphylini are useful
insects, that they are rare in seasons when the white-worms abound,
as was the case, for example, in the years 1867 and 1868. The larva
of the Staphylinus is as carnivorous as the perfect insect, which it
likewise resembles in form.
To sum up: in every phase of their existence, the Staphylini render
immense services to the agriculturist. It is very desirable that
this fact should be generally recognised, and their rehabilitation
generally proclaimed.
THE MOLE-CRICKET.
The habits of the mole-cricket are nearly the same as those of the
mole. When winter approaches, it takes refuge underneath the surface
of the earth, and remains benumbed and lethargic in its nest so long
as the cold lasts. On the welcome return of spring, it makes its way
back to the light by a vertical gallery, on which a great number of
lateral galleries abut, the said lateral galleries being the roads
it travels in pursuit of its prey. This subterranean work it executes
with its strong fore-feet, which are broad, and unguiculated, or
indented, much like those of a mole. Hence its popular name of the
_mole-cricket_ (Fig. 62, _a_).
[Illustration: FIG. 62.]
These insects (of the _Orthoptera_ order) belong to the small family
of the crickets--a family closely akin to that of the grasshoppers.
This close kinship has been recognised by the poets, and we find
them brought together in a very charming sonnet, which cannot be
too frequently perused by any reader, and which may therefore be
introduced as a relief to our duller prose:--
"Green little vaulter in the sunny grass,
Catching your heart up at the feel of June,
Sole voice that's heard amidst the lazy noon,
When even the bees lag at the summoning brass;
And you, warm little housekeeper, who class
With those who think the candles come too soon,
Loving the fire, and with your tricksome tune
Nick the glad silent moments as they pass;
Oh, sweet and tiny cousins, that belong,
One to the fields, the other to the hearth,
Both have your sunshine; both, though small, are strong
At your clear hearts; and both were sent on earth
To sing in thoughtful ears this natural song--
Indoors and out, summer and winter, mirth."
So sings Leigh Hunt--a poet, by the way, whose heart was ever open
at "the feel of June," and whose genial writings, whether prose or
verse, whether delightful essays or melodious songs, should be read
in the "happy summer-time," when the idler, reclining on the sunny
grass, with the beauty of an English landscape around him, wants the
companionship of a gentle spirit and a refined and healthy intellect.
[Illustration: FIG. 63.--The idler, reclining on the sunny grass.]
The mole-cricket is, like the grasshopper, a child of summer. It
differs, moreover, from the "cricket on the hearth" in lacking those
organs of _stridulation_ (excuse the word, kind reader!) which
mark "the glad silent moments" with their tricksome (and sometimes
inconvenient) tune. Their posterior thighs have an apparent bulging
about them, but the legs are very short; so short, that our little
friend could not compete with its cousin, the grasshopper, in
vaulting exercises, even were it not otherwise prevented by its large
abdomen. Nor is it much assisted by its wings, for though they are
broad, they are not organised for rapid flight, and the mole-cricket
makes but little use of them. Nature, however, has compensated it
for all these disadvantages by the gift of those strong, powerful,
flexible fore-feet of which I have already spoken.
The species generally met with in gardens, corn-fields, and orchards
is the _Gryllotalpa vulgaris_ of Latreille, identical with the
_Gryllus gryllotalpa_ of Linnæus. It has a brown head, garnished with
rusty-coloured mandibles; the thorax is of a brownish-gray, velvety,
tinged with red in the fore parts; the elytra, or wing-sheaths, which
are much shorter than the abdomen, are gray, and marked by black and
conspicuously prominent nerves; the wings, folded back like a fan,
are about one-fourth longer than the abdomen.
* * * * *
The mole-cricket,--mark me!--is no more of a root-eater than the
mole; it is carnivorous, like the Staphylinus. As an experiment in
confirmation of this statement, we shut up one of these curious
Orthopteras in a large chest filled with mould. Concealed in the
galleries which it speedily constructed for its use, it fed upon
larvæ, and never touched the cereals which we had sown in the earth.
Here was a proof that we had to plead the cause of another of man's
victims.
The mole-cricket ejects, when pursued or tormented, a blackish
liquid, whose etherealised odour reminds one of the peculiar smell
of certain rotten apples. The female, larger than the male, lays
her eggs, which are, comparatively speaking, of a tolerable size
(Fig. 62, _b_), at some depth underground. The young, when hatched,
resemble their parents, except that they are white, and possess
merely the rudiments of wings.
If the mole-cricket, in its subterranean progress, encounters any
roots, it cuts them with its mandibles, not to feed upon them, but
to get rid of an obstacle; hence the mischief of which the farmer
accuses it, though this slight amount of injury is altogether
outweighed by its services in destroying a swarm of insects.
Perhaps, therefore, we must not blame the farmer for the hostility
with which he pursues it, especially if we are to accept as a true
picture of its doings the sketch recently drawn by a popular writer:--
"It is easy to understand that an insect which undermines land in
this way must cause great damage to cultivation (!). Whether the
crops serve it for food or not, they are not the less destroyed by
its underground burrowings. Lands infested by the mole-cricket are
recognisable by the colour of the vegetation, which is yellow and
withered; and the rubbish which these miners heap up at the side of
the openings leading to their galleries, resembling mole-hills in
miniature, betrays their presence to the farmer."
If, I say, this be a true picture, we cannot wonder at the means
employed by the farmer to clear his fields of such dangerous tenants.
The plan generally adopted is to dig, at intervals, a number of
little trenches, which are filled up with cow-dung, well trodden
down. The supposed root-eaters assemble in these warm nests; and
every fourth or fifth day, a labourer, armed with a pitchfork, scoops
up the manure at a single stroke, and scatters it over the ground,
while another crushes the unfortunate _Gryllotalpæ_ as fast as they
make their appearance.
THE EARWIG.
Next to the domestic fly, the earwig is, perhaps, one of our
commonest, and, let us add, one of our most troublesome, insects.
Whence comes its popular appellation? From a mere fable. To amuse
the silly--alas! how great their number!--marvelling, without doubt,
at the spectacle of an insect's tail armed with strong pincers, some
jester wished to transform it into a terrible animal; and therefore
he pretended that it introduced itself into the human ear, and from
thence penetrated to the brain, with the view of driving out its
proprietor,--_i.e._, the mind or spirit which animates it. Only,
the originator of this absurd bugbear forgot one little fact: there
is no opening by which the ear can communicate with the brain! As
for the pincers, they are not so formidable as they appear. This
character, however, has been considered a sufficient foundation
by the naturalists, even by Linnæus himself, for the insect's
scientific name, _Forficula auricularia_, which is almost literally
translated by the French _oreille-pince_,--our English _earwig_ or
_ear-piercer_. (Fig. 64.)
[Illustration: FIG. 64.--The Earwig (_Forficula auricularia_).]
What dress is to man, their wings are to insects; by these
we distinguish them, at the first glance, from one another.
The elytra,--those horny sheaths which protect the membranous
wings,--embrace, in the Coleoptera, the entire upper surface of the
long annulated abdomen, and resemble vari-coloured _chlamydes_. But
now, look for the elytra of our Forficula. You will hardly believe
that they are represented by this kind of abbreviated light-brown
jacket, which does not extend below the middle of the back. Do you
observe yonder whitish spots? They indicate the tips of the wings,
which are longer than their covers. Lift up one of the elytra with
your penknife, and you will find that the wing which it partly
screens is worth your attention. The fore part (we should call it
the _upper_, if the animal walked erect like a man) is straight, and
without a fold. Raise it with a pin to see the posterior or lower
part. Observe, it curves underneath so as to bind the intermediate
portion like a fan. But this flabelliform wing,--of tolerable
dimensions when unfolded,--seems intended by the Creative Thought
only to mark its unity of plan: the earwig does not fly,--it secures
its food by crawling.
The elytra and the wings, inconspicuous as they are, produced so
great an impression on the early naturalists, that they made them
the principal characteristics of an entire order of insects. De
Geer, a celebrated Swedish naturalist, named them the _Dermaptera_
(from δέρμα, skin, and πτερόν, wing), in allusion to the
transparent skin-like appearance of the elytra. This name, though
adopted by Kirby, has not been preserved. A French entomologist
suggested the designation which is now in use,--_Orthoptera_ (from
ὀρθός, straight, and πτερόν),--referring to the manner in
which the wings are folded underneath the elytra.
* * * * *
Here we must pause to recapitulate for the benefit of our younger
readers, and to avoid confusion, the various orders into which the
insect world is divided.
1. _Aptera_ (from α, without, and πτερόν, a wing),--wingless.
Examples--Flea, louse, chigo.
2. _Diptera_ (δίς, two, and πτερόν),--two-winged. Sub-divided
into Nemocera, having six-jointed antennæ; Brachycera, having
three-jointed antennæ. Examples--Gnat, tipula; May-fly, gad-fly.
3. _Hemiptera_ (ἕμι, half, and πτερόν),--half-winged.
Sub-divided into Heteroptera, with wings of different textures;
Homoptera, with wings of one substance. Examples--Land-bug, water-bug;
cicada, lantern-fly.
4. _Lepidoptera_ (λεπίς, a scale, and πτερόν),--scaly-winged.
Examples--Tiger-moth, butterfly, silkworm.
5. _Orthoptera_ (ὀρθός, straight, and
πτερόν),--straight-winged. Examples--Earwig, cockroach,
locust.
6. _Stymenoptera_ (ὑμήν, a membrane, and
πτερόν),--membranous-winged. Examples--Bee, wasp, ant.
7. _Neuroptera_ (νευρόν, nerve, and πτερόν),--nerve-marked
wings. Examples--Dragon-fly, caddis-fly, ant-lin.
8. _Strepsiptera_ (στρεψις, a twisting, and πτερόν),--curled
or twisted wings. Examples--Xenos, elenchus.
9. _Coleoptera_ (κολεός, a sheath, and πτερόν),--sheathed
wings. Examples--Beetle, cockchafer.
The order of _Orthoptera_, with which we are now concerned, is not
very well known. The reason is, perhaps, that the insects belonging
to it--earwigs, cockroaches, grasshoppers, crickets--are not less
disagreeable than useless, so far as man is concerned. Being nearly
all of them omnivorous, like man himself, they frequently aid him,
very much against his inclination, in the consumption of natural
products of every kind.
It has been remarked that the species of great animals are far fewer
in number than those of the little. This remark applies with peculiar
force to the Orthoptera, which do not include nearly so many small
species as the Coleoptera.
* * * * *
The earwig is the type of the tiny group of the Forficulidæ, of
which two species only are known to the common world--the _Forficula
auricularia_ and the _Forficula minor_.
The first species everybody is acquainted with. We have already
spoken of its elytra and its wings; but we now say a word upon the
two extremities of its body. The two antennæ, which crown the head,
are extremely mobile, owing, of course, to the numerous articulations
of which they are made up. These are fourteen in number (if we
include the base, which is itself composed of two movable parts). In
reality, however, there are but twelve; for we ought to eliminate
the base,--because, in form and size, it differs greatly from
articulations properly so called,--and, at the same time, to regard
as one the articulation or joint inserted in it. In fine, I am of
opinion, contrary to the general conclusion, that the antennæ of the
earwig consist but of twelve articulations, bristling with hairs,
and easily counted almost by the unassisted eye. With the help of a
microscope, the observer can easily distinguish the large nervure
traversing them from top to bottom, and communicating to the antennæ
their characteristic sensibility and mobility.
The brownish-coloured abdomen, composed of imbricated rings, forms,
in itself alone, upwards of half the body. The animal can move itself
in every direction; can bend and twist like a young eel. To the last
of its rings, which is larger than the others, are attached the two
curved branches of the forceps (_forficula_). These are weapons of
defence rather than of attack. At the same time, they are useful as
a sexual distinction. The forceps of the male are strongly arched,
and furnished with indentations perfectly visible to the naked eye
(see Fig. 64, _a_); those of the female are scarcely bent at all, and
their indentations can only be seen with the microscope. In numerous
individuals, the last ring of the abdomen is provided with four
tubercles, one in each side and two in the middle; but this is not a
uniform characteristic.
The earwig is a _trimeral_ insect; that is, its tarsi are each
composed of three joints. Its mandibles are comparatively weak. The
moment you touch it, the insect raises, with great quickness, the
extremity of its supple body, and endeavours to defend itself with
its pincers. The female lays her eggs chiefly in the chinks and
crannies of time-worn timber, and the larvæ issuing from them do not
differ, in any material respect, from the perfect insect. (See Fig.
64, _b_.)
The small species, known as _Forficula minor_, is not very common.
It is about half the size of its better-known congener, and is also
distinguished from it by its joints, ten in number,--by its legs,
of a very pale yellow,--and by its pincers, which are not only very
short, but almost straight, and scarcely marked, even in the male,
with any indentations. More, the wings are of the colour of the
elytra, and without any white spots. This species is chiefly met with
in the spring-time, and then in damp sandy localities, near ponds and
rivers.
* * * * *
Another, and still rarer species, to which we may permit ourselves
an allusion, has yellow pincers, rather black at the extremity,
and garnished inside, towards the middle, with a horny tubercular
projection. In the Pyrenees a species has been found which has no
wings at all, and has therefore been named _Forficula aptera_.
Our readers will now inquire, What is the use of this curiously
constructed animal? Is it not an abomination to the gardener? Well,
we admit that it eats up the leaves of his plants, and the petals of
his flowers, especially of the dahlia; but, on the other hand, it
destroys those far more injurious insects, _thrips_, _aphis_, and the
like.
But it has a peculiar interest for the scientific student from the
point of view of what we may call its _muscular dynamometry_,--its
power of traction, which is far superior to that of our strongest
quadrupeds.
Do you doubt the truth of this assertion? Try, then, the following
experiment.
Fasten to the insect's pincer, or forceps, with a thread, a
halfpenny, which will weigh about two grains, while the weight of
its body, on an average, will not exceed five centigrammes. Give
the insect free course over a sheet of paper, and you will see it
drag along the coin like a light chariot. Our animal is, therefore,
capable of drawing a burden fifty times heavier than its own body.
A man of eleven stone would, in the same ratio, be able to drag
7700 lbs. Neither man nor horse can enter, in this respect, into
competition with the earwig. If all the members of the animal kingdom
were classified according to their power of traction, it is probable
that the post of honour at the top of the list would be occupied by
our despised _Forficula auricularia_.
* * * * *
The idea of a _muscular dynamometry_ of insects is not so new as
one might be tempted to think it. From time immemorial men have
been struck, without being able to account for it, by the enormous
disproportion existing between the weight of a flea and the force or
energy displayed by its extraordinary bounds. Hence the popularity of
a recent exhibition in London of Performing Fleas. Pliny, eighteen
centuries ago, asserted that the muscular strength of the ants
exceeded that of all other animals, if we compared the burden they
were able to carry with the diminutiveness of their bodies. "_Si quis
comparet onera corporibus earum, fateatur nullis portione vires esse
majores._"[71]
In the seventeenth and eighteenth centuries, this interesting
question was taken up by Borelli, Lahire, Buffon, and Gueneau de
Montbeliard. Recently it has been revived, with much ability, by
Felix Plateau, whose experiments have proved that the insects, in
comparison with their weight, possess an uncommon muscular force, far
beyond that of vertebrate animals; that in the same group of insects
this force varies in different species; and that in the small species
it is often of astounding energy.
The muscles are enclosed in solid sheaths (so to speak), which
constitute the jointed limbs of insects, and the thickness of the
sides of these sheaths seems to decrease in ratio with the size. No
relation, therefore, exists between the stature of individuals and
the volume and strength of their muscles. A giant may be weaker than
a dwarf. Here is another mystery for science to reveal!
* * * * *
But we must take leave of our earwig. Its English name is derived by
some authorities from _ear_, and the old English _wiega_, a worm or
grub,--identical with the German _oberwurm_, and based, of course, on
the fiction which we have already exploded.
Newman, however, suggests a somewhat different name, and,
consequently, a different etymology:[72]--"The shape of the hind
wings," he says, "when fully opened, is nearly that of the human ear;
and from this circumstance it seems highly probable that the original
name of this insect was _earwing_." But we cannot agree with Mr
Newman.
It remains to be added, that the female earwig sits upon her eggs,
and hatches them like a hen; and like a hen, too, she gathers her
young around her with evident affection.
[Illustration: FIG. 65.--Landscape.]
FOOTNOTES:
[Footnote 58: "The term _perianth_ is usually confined to the flowers
of Endogens, whatever colours they present, whether green, as in
asparagus, or coloured, as in tulip. Some use the term as a general
one, and restrict the use of _perigone_ to cases where a pistil is
present, not applying it to unisexual flowers, in which stamens only
are produced."--_Professor Balfour, "Manual of Botany_," p. 169.]
[Footnote 59: Homer, "Odyssey," Book xix., line 520.]
[Footnote 60: Grew, "Anatomy of Plants," p. 147.]
[Footnote 61: Barry Cornwall.]
[Footnote 62: Tragus, "Historia Stirpium," p. 310 (ed. 1552).]
[Footnote 63: Fabius Columna (Fabio Colonna), an Italian man of
science, who died in 1650, at the age of eighty-three.]
[Footnote 64: Thomas Campbell.]
[Footnote 65: Anne Pratt, "Flowers and their Associations" (ed.
1846).]
[Footnote 66: _Draba aretoides_ has been found on Chimborazo at
16,000 feet.]
[Footnote 67: _Poa annua_ grows at an elevation of 7400 feet.]
[Footnote 68: Aristotle, "Hist. Animal.," i. 9.]
[Footnote 69: Pliny, "Hist. Nat.," xi. 52.]
[Footnote 70: Pliny, "Hist. Nat.," xxx. 7, 12, 24.]
[Footnote 71: Pliny, "Hist. Nat.," xi. 36.]
[Footnote 72: Newman, "Introduction to the History of British
Insects."]
BOOK IV.
AUTUMN.
"Where are the songs of spring? Ay, where are they?
Think not of them; _thou_ hast thy music too,
While barred clouds bloom the softly dying day,
And touch the stubble-plains with rosy hue;
Then in a wailful choir the small gnats mourn
Among the river shallows, borne aloft
Or sinking as the light wind lives or dies;
And full-grown lambs loud bleat from hilly bourn;
Hedge crickets sing; and now with treble soft
The redbreast whistles from a garden croft,
And gathering swallows twitter from the skies."
--KEATS.
* * * * *
"It was a fair and mild autumnal sky,
And earth's ripe pleasures met the admiring eye,
As a rich beauty, when her bloom is lost,
Appears with more magnificence and cost."
--CRABBE.
[Illustration]
CHAPTER I.
_WHAT MAY BE SEEN IN THE HEAVENS._
"The contemplation of the works of creation elevates the mind to
the admiration of whatever is great and noble, accomplishing the
object of all study, which is to inspire the love of truth, of
wisdom, of beauty, especially of goodness, the highest beauty,
and of that supreme and eternal Mind which contains all truth and
wisdom, all beauty and goodness."--MARY SOMERVILLE.
[Illustration]
To discern the luminous point which should guide us in the shadows of
the infinite, is the gift of genius. The first to discern this point
in astronomy, the illustrious Kepler thereby succeeded in formulating
those laws, or rather rules, by which the movements of the stars are
regulated. How did he succeed? How did he arrive at a goal so much
to be desired? By intelligence in full possession of itself. It was
by abstracting his thoughts from all systematic conceptions,--the
shackles of science; it was by defying the traditional authority
which had so long enslaved men's minds; it was by interrogating
nature, which leaves all liberty to her interrogator, that Kepler
was able to deserve and win the glorious title of "legislator of
the heavens,"--a title which we must not, however, understand too
literally; it bears witness only to the power of intellect.
Let us attempt, at a modest distance, to proceed like Kepler; let us
make astronomy without troubling ourselves concerning astronomers.
This is the sole means of seizing the luminous point which should
guide our steps.
* * * * *
The movement, in virtue of which every star performs the circuit
of heaven in four-and-twenty hours, is incessantly reproduced in a
uniform and a constant manner. The acquisition of this first fact,
simple as it seems, was a somewhat laborious task, and undoubtedly
dates back to a distant antiquity. But now comes another fact, where
observation demands the closest mental attention, and which is of a
more recent discovery.
To comprehend it clearly, let us first call to mind that the moment
when the sun crosses the Equator,--whether to return into the
northern hemisphere (at the _spring equinox_), or into the southern
(at the _autumn equinox_),--is instantaneous. More than one way
exists of determining this moment exactly; but here we need not enter
upon the subject.
Is the interval of time occupied by the sun in travelling from the
spring to the autumn equinox equal to the interval which our luminary
requires to pass from the autumn equinox to the vernal?
A singular question, you reply. Who, indeed, would venture to
maintain that the number of days, hours, minutes, seconds, was not
exactly the same in the one case as in the other?
Well, the period is _not_ the same; and, therefore, merely to
propound _this_ question was a masterpiece of genius. For no ordinary
intellectual audacity was needed to doubt the reality of the supposed
perfect circle which the sun apparently describes--according to the
recognised authorities--in its uniform progress around the globe;
that globe believed by all the early astronomers to be imperturbably
and everlastingly situated in the centre of their thrice-sacred
geometrical figure. This dogma being accepted as infallible, there
was every evidence that the two intervals of time, which divided the
astronomical year into two moieties, would be of equal duration. It
did not occur to the mind of any one of the faithful that the sojourn
of the sun, in his circular and uniform movement, might be longer or
shorter in the northern than in the southern hemisphere.
What, then, was the name of the audacious innovator who ventured upon
putting forth so revolutionary a suggestion?
It was Hipparchus. At least it was he who, confidently relying upon
his observations, was the first to affirm that the sun remains longer
in the northern than in the southern hemispheres; or, more accurately
speaking, that its passage from the spring to the autumn equinox
occupies 187 days, while from the autumn to the spring equinox the
duration of its course is only 178 days 6 hours (nearly). The year
of 365-1/4 days--that is, the Egyptian year, which was universally
adopted by the ancient astronomers--was thus discovered to be really
divided into two unequal portions, although, _theoretically_, the sun
ought to occupy exactly the same space of time in passing from the
spring to the autumn, as from the autumn to the spring equinox.
* * * * *
The fact pointed out and attested by Hipparchus had an influence
which he never anticipated on the progress of science. In opposition
to all the systems previously designed by man, it followed, in the
first place, that the movement of the sun, in relation to a mean
movement, must sometimes be accelerated, sometimes be retarded; that
the solar arc described in a given time would be greater in winter
than in summer.
Astronomers who, trammelled by particular theories, were unable
and unwilling to accept of any new light, immediately hastened
to raise, as is invariably the case with those who defend a bad
cause, a subsidiary and damaging question. They asked whether those
inequalities of the sun's movement were real, or only apparent;
whether they were more than a mere optical phenomenon, arising
from the sun's position _vis-à-vis_ to an observer placed on the
earth's surface. And they unhesitatingly pronounced in favour of the
appearance, and against the reality.
But man, says an old adage, is always punished after the manner
of his sin. Dogmatic and obstinate authority involved our
anti-revolutionary astronomers in fresh complications. Such is the
case, too, very frequently, in the domain of theology!
Does the sun--the sun as each of us beholds him--ever change his
size? Does he ever shrink in his majestic proportions? Is the
magnitude of his broad golden disc ever lessened?
* * * * *
Assuredly this new question, which was not less audacious than its
predecessor, did not come--there is sacrilege in the thought--from
the conservative areopagus of all ancient doctrines; the learned
areopagus, or supreme tribunal, which had erected into a dogma the
circular orbit and uniform movement of the sun around the earth, the
centre of the universe! It could only have been suggested by some
unworthy heterodoxical disturber of men's minds,--his name, alas! has
not been handed down to us,--who had dared to look upon the heavens,
and learn from their bright and beautiful face, without a master, the
A B C of science. This "pestilent heretic" had, probably, remarked
one of the commonest phenomena connected with the celestial bodies,
which astronomers hitherto had not deigned to notice.
Undoubtedly, dear reader, you will have been more than once impressed
by the appearance of the solar orb, when obscured in one of those
mists so frequent towards the end of autumn:--
"Cold grew the foggy morn, the day was brief;
Loose on the cherry hung the crimson leaf;
The dew dwelt ever on the herb; the woods
Roared with strong blasts, with mighty showers the floods."
[Illustration: FIG. 66.--"When the glory of the woods is rapidly
departing."]
Such a day, in this sad season of the year, when the glory of
the woods is rapidly departing, and from the swollen streams and
dewy pastures the vapours ascend in a dense whirl of clouds, is
of frequent occurrence; and on such a day, the solar sphere, as
it struggles through the screening mists, seems like the face of
the moon at its full, when slightly veiled. Your eye rests upon
it without pain. And as observation sharpens your mind, you put
to yourself the natural question, Is not the sun farther from the
earth at this epoch when it affords us the least heat, than at that
period of the year when its vivifying power is greatest? I think it
is obvious that, to the unexperienced, such a method of explaining
the cold of winter and the heat of summer by the variation in the
distance of our great solar luminary would naturally occur.
But the demon of certainty--an excellent demon, whatever the orthodox
may say--is present, to stimulate us all. You may have just formed
your theories, you may cite your traditional authorities, but these
will not satisfy our awakened curiosity. We ask for demonstrations,
for irrefragable proofs drawn from the Bible of Nature. We will
listen to no oracles but those which are confirmed by the voices of
God's second revelation.
Therefore, men required to be assured that the sun was really nearer
to us in summer than in winter. For this purpose, it was requisite
to make, at the beginning of summer, an observation analogous to
that which had been made at the beginning of winter, and afterwards
to compare the apparent magnitudes of the solar disc at these two
opposite periods of the year.
Behold us, then, at work. You are perfectly tranquil as to the
result; for you are persuaded beforehand that the sun _must_ be
farther from us in the cold season than in the hot. You regard this
as a self-evident truth, like an axiom of Euclid's.
But Nature is a great magician; she contrives the most dramatic
surprises for the mind which takes the trouble to interrogate her in
all simplicity and without dogmatic pretensions.
What a _coup-de-théâtre_ it was for the observer who first
established experimentally that the apparent diameter of the sun is
greater in winter than in summer--that we are _nearer_ the sun in the
cold season, than in the hot!
* * * * *
On more closely examining a result apparently so paradoxical, man
discovered that the angle which subtracts the sun, as seen from
the earth,--the _visual angle_ which gives the sun's apparent
diameter,--varies necessarily throughout the year. Thus, the
semi-diameter, or radius, which on the 24th of June equals 15' 45",
will, a month later, have increased one second (15' 46"); on the 2d
of August will equal 15' 47"; on the 2d September, 15' 53", and so
on. We put the exact measurements before the reader in a tabulated
form:--
LENGTH OF THE SUN'S RADIUS.
On January 21, 16' 16"
" February 25, 16' 10"
" March 31, 16' 1"
" April 30, 15' 53"
" May 30, 15' 47"
" June 24, minimum, 15' 45"
" July 24, 15' 46"
" August 3, 15' 47"
" September 2, 15' 53"
" October 2, 16' 1"
" November 6, 16' 10"
" December 21, maximum, 16' 17"
We do not trouble the reader with the fractions of a second, which
indicate the quantity of the apparent increase of the radius from the
end of June to the end of December, and its apparent decrease from
the beginning of January to the end of June.
* * * * *
A glance at the above figures shows that the mean of the apparent
diameters, all measured at the moment of the sun's passing the
meridian, is about half a degree, or 30'; and that--which is
sufficiently curious--720 of these mean suns, set one against
another, would be required to fill up the contour of a great circle
of the celestial sphere. Is it this fact which suggested the idea of
dividing the circle into 720/2 = 360°?
* * * * *
Simultaneously with the discovery of the variations of the solar
charioteer, it was ascertained that the moments of the sun's passage
of the meridian--moments which measure the 365 different positions
occupied by the sun in the 365 days of the year--are not separated by
equal intervals, or that equal intervals of time do not correspond
to the equal angular displacements,--in fine, that the maximum and
minimum of the sun's angular velocity coincide with the maximum and
minimum of its apparent diameter. Now, remember that the extreme
points where the sun experiences its maximum and minimum angular
displacement are named, according to Ptolemæus, the former the
_perigee_, the latter the _apogee_; or, if we follow Copernicus, the
former the _perihelion_, and the latter the _aphelion_.
The aggregate of these facts was known to the ancients; but the
manner in which it was sought to explain them merits notice as a
specimen of blind attachment to a preconceived system.
Ptolemæus, the organ of the dictatorial astronomy of antiquity,
declares, _ex cathedrâ_, that "the inequalities of the sun's
movements are only apparent; that they are simply the effects of
the position and of the arrangements of the circles in which these
movements are accomplished; and that, in this _apparent disorder of
the phenomena_ (περί τὴν ὑπονουμένην τῶν
φαινομένων ἀταξίαν), nothing really occurs contrary
to their actual immobility (τῷ ὄντι πέφυκε
συμβαίνειν οὐδὲν ἀλλότριον αὐτῶν
τῆς ἀΐδιοτητος)."
Now, according to this dogmatic immutability, the straight lines, or
radii, which proceed from the revolving star to the centre of the
circle, would describe "equal angles in equal times." This is exactly
the contrary of the result obtained, as we have seen, by careful
observation.
But this difficulty no more embarrassed the great pontiff of
astronomy than a conscientious scruple would perplex the author of a
theological dogma. Listen to him:--
"The true cause of these apparent irregularities is explained by two
very simple hypotheses. Either the one or the other would account
for the phenomena. In fact, if we suppose the movement to occur in
a circle described around the centre of the world, and in the plane
of the ecliptic, so that the point whence we are looking corresponds
with this centre, we must admit either that the planets make their
movements equal in non-concentric circles, or that, if these circles
are concentric, it is not simply in these circles that they move, but
in others, called _epicycles_, carried through the concentric."[73]
Examine Fig. 67. Here A B G D represent the ecliptic, E its centre,
and A E G its diameter; Z H T K is the epicycle, in which the planet
moves uniformly around the centre A, while the epicycle uniformly
traverses the circle A B G D. Now, suppose that the star has arrived
at H; it would appear to an observer at E to be more advanced by the
uniform movement of all the arc A H; if it be at K, it would appear,
on the contrary, to be less advanced by all the arc A K. At Z the
star would appear more distant, and at T, nearer than if it were at A.
[Illustration: FIG. 67.--The Circle and the Epicycle.]
* * * * *
To explain the other phenomena, such as the stations and
retrocessions of the planets, recourse was again had to the epicycles
or deferred eccentric circles. By multiplying these it was possible
to account for all the angular inequalities in the movements of a
planet. It is of importance to note this point, in order to show
how very dangerous it is to trust absolutely to mathematics in our
search after the truth; that science which, by the certainty of its
demonstrations, nourishes our intellectual pride, and may, therefore,
occasionally lull the mind into a false security. The theory of
epicycles, from a mathematical point of view, was irreproachable, and
it sufficiently accounted for the facts which threatened to overthrow
the dogma of circular orbits and uniform planetary movement.
* * * * *
But by degrees, as observations grew more accurate and
comprehensive, these and other theories, however fine in
appearance,--_teres atque rotundus_,--gradually disappeared, if
fundamentally erroneous. By the invention of micrometers, we were
enabled to measure more exactly than had formerly been possible
the variations of diameter or the modifications of distance, and
afterwards to compare them with the changes of velocity. From
this comparison it results that the latter are not greater than
is compatible with the alterations of distance indicated by the
variations of diameter; in a word, that the hypothesis of epicycles
is decidedly insufficient to account for all the inequalities
detected by careful investigation.
* * * * *
Kepler was the first to break the charm which had held captive the
mind of astronomers, including even Copernicus and Tycho Brahé.
Ptolemæus had considered the mean positions of the stars to be
real. Kepler, strong in his researches, declared that they were
but a factitious mode of calculation by which the _true_ positions
might be ascertained; that the mean movement is simply an artifice
representing the star's place, _if_ no inequality existed; in fine,
that we must take the movements as they are in nature,--the true
movements, given by observation,--and not the mean movements, deduced
from an erroneous hypothesis.
This declaration of principles met, at the time, with the hostility
of all astronomers of any reputation, but it has become the
starting-point of the discovery of the laws on which the whole
edifice of astronomy reposes. Had Kepler, however, been left to
depend entirely on his own resources, he might, perhaps, have
never completed his task. A fortunate circumstance brought him an
unexpected ally. Tycho, having taken refuge in Bohemia, sent for the
young astronomer (Kepler then was but twenty-nine years old), to
assist him in the composition of the "Rudolphine Tables."[74]
"This," says Kepler, "was a providential interposition. I repaired
to Bohemia early in the year 1600, in the hope of learning the
correction of the eccentricities of the planets. Perceiving that
Tycho made use of a mixed system (which made Mercury and Venus
revolve around the sun, and all these planets, with their companions,
around the earth), I asked his permission to follow out my own
ideas. It was the will of Providence again, that we should occupy
ourselves with Mars. My whole attention, therefore, was directed to
this planet: and it is through the movements of Mars we must obtain
our insight into the secrets of astronomy, or remain ignorant of them
for ever (_ex Martis motibus omnino necesse est nos in cognitionem
astronomiæ arcanorum venire aut ea perpetuo nescire_)."[75]
Why this preference given to Mars? In the first place, because, among
all the planets then known, it was Mars which, in its movement round
the sun, departed most from the circle; next, its orbit approaches
nearest to the earth's; the earth is very near to Mars when she
passes between that planet and the sun,--that is to say, when she is
in _opposition_, while she retires from it triple the distance when
in _conjunction_,--that is, when the sun is between her and Mars.
Hence arise certain variations of aspect, particularly adapted to
make manifest the form of the orbit, and the law of the real movement
of the "red planet, Mars." As for the other planets, as far as they
were then known, their orbits differ so little from the circle, that
the nature of the curve which they describe in reality would never
have been exactly recognised by any inexperienced star-gazer.
For these reasons Kepler regarded as providential the choice he had
been led to make of Mars at the outset of his astronomical career.
Before the close of 1601, Tycho died, bequeathing to his young
fellow-worker a treasury of observation. Thenceforth Kepler undertook
to finish without assistance the famous Rudolphine Tables. They cost
him five-and-twenty years of assiduous labour. Looking upon Tycho's
observations, because of their exactness, as "a gift from the Divine
Goodness," he employed them, in the first place, as a test of the old
hypotheses of planetary orbits and movements. Let us do our best to
grasp the range and bearing of this part of his work.
* * * * *
In the system of Copernicus, which Kepler ardently adopted, the
earth revolves around the sun. Now, observation having shown that
the sun remains seven or eight days longer in the northern than in
the southern signs of the Zodiac, we must of necessity admit that
the sun, instead of being situated in the centre of the terrestrial
orbit, occupies a point _outside_ that centre, in such a manner that
the earth must sometimes be nearer to, and sometimes farther from,
the sun. The distance by which it departs from the centre of its
orbit, which Copernicus, like the ancients, supposed to be circular,
is called its _eccentricity_.
Astronomers were long preoccupied with the idea of seeking in this
_eccentricity_ a point where the movements should appear equal. This
point was the centre of the _equant_,--a name given to the eccentric
circle described from the point of equality or from the centre of the
mean movements.
Now, let us recall the principal condition of the problem which
Kepler had undertaken to solve. This condition required that the
straight line drawn from the centre of our globe to the centre of the
sun,--in a word, that the _vector radius_, as it is called, should
describe around the sun certain angles, whose variability should
agree with the results of observation.
Starting from this point, Kepler found that, for certain positions
of Mars (in the _aphelion_ and _perihelion_, corresponding to the
_minimum_ and _maximum_ of velocity), the centre of the orbit,
always supposing it to be circular, divided into two equal parts
(or _bisected_) the total eccentricity: in other words, that it
exactly occupied the middle between the centre of the eccentric and
the _equant_ of Ptolemæus; but it did not appear to him necessary
to bisect it in other positions, intermediate between those of the
aphelion and the perihelion. He established that the differences
in longitude amounted to eight or nine minutes. Now, observations
so exact as those of Tycho were altogether incompatible with such
great error.[76] Therefore, the geometrical hypothesis which gave
these errors was false; the orbit of Mars could not be a circle, and
to save these eight or nine minutes, furnished by observation but
in disaccord with theory, it would be needful to recommence all the
calculations of astronomy. This conclusion, not less legitimate than
daring, supplied Kepler with the first decisive step in the task he
had undertaken.
This is not the place to relate all the essays and miscarriages
through which this man of genius passed before finally completing his
discovery of the rules that bear his name. But we may put before the
reader the construction which led to them.
On a sheet of paper let us mark down by a point (Fig. 68) the place
occupied by the earth in relation to the sun.[77] From this point
_o_, we draw a right line terminating at _a_, the sun's noon-day
position (for example, on the 1st of January); the succeeding lines
shall touch upon _a´ a´´_, which the sun occupies successively after
the same interval of time (twenty-four hours, or the exact duration
of the earth's rotation on its axis);--and let us continue after
this mode until the sun has accomplished, by its own proper movement
from west to east, the whole circuit of the heavens, traversing
360 degrees in the space of a year. If we ascribe to the radius
_o a_ a certain length, corresponding to a definite solar diameter,
the lengths of all the others, corresponding to the variations of
the same diameter, will depend upon that of the first, which, for
facility of calculation, we suppose to be divided into one thousand
parts.
[Illustration: FIG. 68.--Diagram for Kepler's Laws.]
After having thus allotted to each straight line its approximate
length, let us join their extremities by a curve. What do we see
before us? A geometrical figure widely different from a circle, for
the diameters (_i.e._, the straight lines passing through the centre)
are far from being equal. The figure is an ellipse.
If now we pass from the appearance to the reality, _o_ will be the
sun, and _a a´ a´´_, _m m´_ will indicate the terrestrial orbit,
or the points of the curve successively occupied by the earth in
movement. The moveable straight lines, free at one extremity, and at
the other attached to the centre of the sun, are called the _Vector
heliocentric radii_. By the help of this construction, you see that
the point occupied by the sun is beyond or without the centre; this
eccentric point is the _focus_ of the ellipse, and the distance
from this focus to the centre, its _eccentricity_. The extremity
of the major axis, the nearest to the focus, is the _perihelion_,
and its farthest extremity the _aphelion_. The difference of the
angles formed by the vector radii indicate the inequality of the
movements: to the greatest angle, the perihelion, corresponds the
_maximum_ of velocity (_a a´ a´´_), just as to the smallest, or
aphelion, corresponds the _minimum_ (_m m´_); the other angles mark
the velocities intermediary between these two extremes. We have thus
before us a series of triangles with their apices at the focus of the
ellipse, and their bases on the contour of the curve.
But these latter are not sufficient for the mind, whose principal
function lies in seeking unity among the variety of phenomena.
In what way are the variations of distance connected with the
variations of velocity? What is the simplest expression of their
relationship? These are questions which naturally presented
themselves to Kepler's inquiring intellect. By dint of immeasurable
patience, and recommencing more than once the same toil, this great
astronomer discovered that the variable arc traversed by the earth
(or, in appearance, the sun), in four-and-twenty hours, multiplied by
one half the corresponding vector radius, is a constant quantity: is
the product which, as elementary geometry teaches, gives the surface
of a triangle. And, in fact, look at the matter carefully: the
_vector radii_ form triangles whose base is the arc traversed in the
same interval of time, and whose apices rest upon the centre of the
sun (or, in appearance, the observer, or the centre of the earth).
To fix these ideas thoroughly in our minds,--and a superficial
knowledge is worse than useless,--let us imagine to ourselves a man
holding horizontally extended a tube of a certain length, capable,
like a telescope, of being lengthened or shortened at pleasure;
and let us fancy him pivoting upon himself, in such a manner that
he sweeps, every minute, exactly the same area or same quantity
of surface, while varying perpetually the swiftness of movement
and the length of the tube; this "ideal man" will have solved the
problem whose solution is inscribed, in ineffaceable letters, on the
machinery of our globe; he will describe around him an ellipse, of
which he himself occupies one of the foci.
* * * * *
By this method of investigation and deduction, Kepler succeeded in
breaking up the traditionary authority of the circle and of uniform
movement. He broke it up for ever by two of his celebrated laws,
which may be rendered in the following terms:--
1st, _The orbit of the earth, as well as the curves described by
the other planets, are ellipses, one of whose foci is represented
by the sun_;
2d, _The heliocentric vector radius of a planet describes around
the sun areas equal with the times; or, in other words, the
surfaces described by the vector radii, in equal times, are also
equal._
The ancients had looked for equality in the movements of planets
traversing the circumferences of circles: they were mistaken. It is
true this equality exists; only, not where they supposed. If they had
sought it in the surfaces described by the vector radii, they would
have anticipated Kepler's discovery of the laws which govern our
world.
But their astronomical dogmas prevented them from seeing the path
which led to this great discovery.
Hence we may conclude that Dogma is an evil thing.
[Illustration]
FOOTNOTES:
[Footnote 73: Ptolemæus, "Syntaxis Mathematicalis," iii. 3.]
[Footnote 74: Certain astronomical calculations, so called because
begun under the patronage of Rudolf II., Emperor of Germany
(1576-1612).]
[Footnote 75: Kepler, "Astronomia Nova, seu de Motibus Stellæ
Martis," p. 53 (ed. 1609).]
[Footnote 76: The reader should turn to Kepler's immortal work, "De
Motibus Stellæ Martis," for the manifold attempts of the astronomer
to bring calculation into agreement with observation. In every page
is revealed what has been finely called "the passionate patience of
genius."]
[Footnote 77: There is certainly no exaggeration in comparing the
earth to a point, since the diameter of the sun is 112 times that
of the earth, and its mean distance a little more than 12,000
terrestrial diameters: the earth is but a microscopical point
in space, if we compare it to the place occupied by the central
luminary.]
[Illustration]
CHAPTER II.
_WHAT MAY BE SEEN UPON THE EARTH._
"I care not, Fortune, what you me deny;
You cannot rob me of free Nature's grace;
You cannot shut the windows of the sky
Through which Aurora shows her bright'ning face;
You cannot bar my constant feet to trace
The woods and lawns by living streams at eve."
[Illustration]
Of all the strata composing our planetary mass, the most important,
so far as man is concerned, is, at the same time, the most
superficial; for it is here that all the phenomena of life transpire.
Our vegetable earth is the great laboratory in which are prepared all
the solid, liquid, and gaseous aliments necessary for the nourishment
of animal life. It is on the surface of the globe that men play
their various parts. And why? Can it be for no other purpose than to
modify, in some degree, its aspect, that they occupy the terrestrial
surface? One would be tempted to think so on consulting what these
majestic _bimanes_ pompously designate their "Universal History."
Regions formerly blooming with fertility,--gay with gardens, and
orchards, and meadows,--musical with brooks, and glorious with
harvest,--are now uncultivated and barren. Monuments which seemed
adapted to defy the winds and the rains, and the corroding touch of
the years, lie shattered in ruins; and with them the once populous
cities and the once mighty empires of which they were the pride. The
jackal howls among the broken columns of Tadmor; the sand-drifts have
accumulated above the splendour of Memphis and Thebes. With their
stones other monuments are raised, other cities are embellished, and
other empires, which, in their turn, undergo the same unalterable
fate: a perpetual relation of human forms, in every respect
comparable with that which transpires in the bosom of the prolific
earth, our common mother and nurse.
But why do men wander so far from the straight way? Why do they their
best to ensure each other's unhappiness? They seem, alas! ignorant of
the tendency of their actions, while attaching themselves to things
transitory, and despising things imperishable. These, indeed, they
would utterly ignore; they would live, like the brutes, unconscious
of their destiny, if, at the bottom of their indestructible
conscience, there did not prevail a glimmer of light, though more
or less eclipsed, if they did not all feel themselves attracted, if
they did not all irresistibly gravitate, some more quickly, others
more slowly, towards the sun of eternal truth and justice. Instead
of moving with sidelong sinuous pace, instead of taking ninety-nine
steps backward for every one hundred taken in advance, they would
all march onward in the way of progress; were it not that they pass
their time in clipping their own wings; were it not that, to bend
their heads the better--_Veluti pecora ventri obedientia_--they
check the aspiring flight of that thought which would soar beyond
the present; in a word, were it not that they lay a sacrilegious
hand--unfortunate wretches!--on that which God Himself has respected
in His creature--Liberty! The doubt which perplexes us as to the
great problem of our destiny,--the doubt which allows so much
latitude to the workings of our conscience,--does it not indicate the
path we ought to follow? Should not men regard their freedom with
peculiar reverence, when the Divinity they invoke has mercifully
refrained from fettering it? Creatures of a day, who live as if you
would never die! the contradictions and the miseries of which you so
incessantly complain, are your own work. Help, help yourselves, by
the development of your faculties, by the cultivation of your heart
and mind, for herein you shall see the law and the prophets. Barren
lip-service is nothing better than blasphemy!
* * * * *
But let us return to the ground which we tread, and where our
life-companions are the animals and the plants.
* * * * *
The uppermost stratum of our globe undergoes the direct action of
the light and heat of the all-vivifying "orb of day." This action,
very unequal in its effects, and most important to understand, has
scarcely been touched as yet by scientific research. Our geologists,
having been more busily engaged with the inside than the outside
of the earth, have broached certain plausible theories--for the
most part of a very dubious character--respecting the central fire,
Plutonism and Neptunism, the stratification of the planets, the
formation of mountains, valleys, and basins. Our mineralogists,
thinking far less of the chemical molecular constitution of the
different formations than of their crystalline constitution, have
minutely studied the physical qualities and geometrical forms of the
integral parts of the rocks; but neither have condescended to direct
their inquiries to the layer of soil trodden underneath their feet.
Yet this very layer of arable earth, to which all bodies must return
after death what they have taken from it during life,--this much
despised _humus_, furnishes all our agricultural products, the very
foundation and support of our material existence.
To touch industrial occupations--to meddle with trade, commerce, or
agriculture--is unworthy of Science! Such is the silly cry of the
many distinguished savants who pride themselves on what they call
their "freedom from selfish considerations."
Be it so; but then you ought surely to be consistent, and never
regard science as a profession or a bread-winner.
ON THE CHEMICAL ACTION OF LIGHT.
It is no easy study to investigate the modifications and chemical
effects which the terrestrial surface is capable of receiving or
undergoing, either from the direct rays of the sun, or from diffused
light. It requires new methods of inquiry,--methods frequently
of extreme delicacy, as the labours of Bunsen and Roscoe, of
Kirchhofer and Tyndall, have abundantly demonstrated. Let us here
confine ourselves to establishing the fact that the chemical action
of light varies according to the geological constitution of the
soil,--according to the diurnal and annual obliquity of the solar
rays,--according to the hours of the day,--according to the latitudes
and seasons. The maximum of effects is manifested about the times of
the solstices.
For the better co-ordination of these phenomena, might we not, as has
been done in regard to the distribution of heat over the terrestrial
surface,[78] link together by lines the points of equality? We should
thus create an aggregate of _iso-photo-chemical_ lines,--diurnal,
mensual, and annual,--of incontestible utility for the progress of
general physics and meteorology, which are still in their infancy.
But to realise this magnificent programme, the union and agreement is
necessary of scientific men in every region of the globe; an ideal,
therefore, as yet, is very far from being attained.
THE ACTION OF HEAT.
The earth is subject to the influence of two different sources of
heat. One, like the arterial blood, strikes from the centre to the
circumference: this internal heat it is which has been stored up
since the unknown epoch when our globe was nothing more than an
incandescent nucleus, surrounded by condensable vapours. The other,
like the venous blood, flows from the circumference towards the
centre: this is the solar heat which the earth continues to receive
through its crust.
The first of these sources lies beyond the domain of experiment. It
has been the object of numerous hypotheses and diverse speculations,
with which we shall not here concern ourselves. The second source
is alone accessible to our investigations, and yet the network of
_isothermal lines_ is scarcely defined.
Since the year 1817, when Alexander von Humboldt conceived the
felicitous idea of representing by lines the same mean temperatures
enjoyed, in a given space of time, by the different regions of the
globe, researches of this nature have very considerably multiplied.
But these researches--do not forget--refer rather to the temperature
of the atmosphere than to the heating of the inferior stratum of that
gaseous ocean whose bed or foundation is the terrestrial crust. And
it is the penetration of the latter by the sun's calorific rays which
we would especially desire to understand. Here, then, a sufficient
margin is left for our curiosity.
"If the king, my father, does not rest from his conquests," cried
Alexander of Macedon, while still a child, "he will leave me nothing
to do when I shall have reached manhood." To such a complaint, be you
sure, dear reader, that the conquests made by science will never give
rise. Every step in advance is but a step into the infinite: what we
have done only shows us the boundless extent of what we have to do.
It is this reflection which must always teach humility to the
scientific student, even while he rejoices in the achievements of
human patience and genius. He will not despair for he knows that
great victories have been won: he will not grow arrogant, for he
knows that he is still on the threshold of eternal truth. As Sir
J. Herschel has justly said:--"He who has seen obscurities, which
appeared impenetrable, in physical and mathematical science, suddenly
dispelled, and the most barren and unpromising fields of inquiry
converted, as if by inspiration, into rich and inexhaustible springs
of knowledge and power, on a simple change of our point of view, or
by merely bringing them to bear on some principle which it never
occurred before to try, will surely be the very last to acquiesce
in any dispiriting prospects of either the present or the future
destinies of mankind; while, on the other hand, the boundless views
of intellectual and moral, as well as material relations, which open
to him on all hands in the course of these pursuits,--the knowledge
of the trivial place he occupies in the scale of creation, and the
sense continually pressed upon him of his own weakness and incapacity
to suspend or modify the slightest movement of the vast machinery
he sees in action around him, must effectually convince him that
humility of pretension, no less than confidence of hope, is what best
becomes his character."[79]
The temperature of the terrestrial surface perpetually varies under
the influence of local as well as general causes. Had this fact
been known to the philosophers of antiquity, they would have taken
advantage of it to liken the earth to an animal whose skin is more or
less sensible of heat, not only according to the difference of the
seasons, but according to the different hours of the day.
The diurnal thermometrical variations are those which penetrate the
least profoundly into the interior of the soil. At a depth of about
five feet they cease to be perceptible. The maxima and minima of the
year, however, can be detected at a sufficiently considerable depth.
The limit descends as low as 80 to 100 feet. Below 100 feet, the
terrestrial stratum is found invariable,--that is, inaccessible to
the thermometrical changes of the atmosphere. It is remarkable that
the temperature of this stratum differs but little from the mean
annual temperature of the air, which, in the latitude of London, is
49°.
* * * * *
The maxima and minima of the yearly heat are propagated very slowly
in the earth, and their difference gradually becomes less and
less. Thermometers buried 26 feet deep in the ground, mark, in our
latitudes, the maximum of temperature only on the 10th of December,
and the minimum on the 15th of June. But there are certain elements
which we must take into account. Thus, the depth of the invariable
thermometrical curve depends both on the latitude of the place,
on the conductibility of the strata, and the difference between
the highest and lowest temperature of the year. The less this
difference, the more nearly does the invariable stratum approach the
surface. Here we have the reason why, in the intertropical torrid
zone, where the temperature scarcely varies above two or three
degrees in the whole year, the invariable curve is not found more
than forty centimetres beneath the surface.
* * * * *
In the temperate zone, lying between the torrid and the frigid zones,
the same phenomena assume, apparently, a more complex character;
the isogeothermal lines inflect as diversely as the isothermal, and
the former are far from running parallel with the latter. And this
is easily understood, even without any experiment, for there is no
relation between the ever-varied composition of the terrestrial
strata, and the much more uniform composition of the atmosphere.
In the frigid zone, the soil remains constantly frozen for an
insignificant depth, whatever may be the temperature of the
encircling atmosphere. In some regions a stratum of ice and snow
eternally reposes on the surface of the soil.
Unfortunately the observations, which require to be undertaken on an
uniform plan and under well-weighed conditions, at various points
over the whole globe, are as yet far too few to assist us in defining
any general currents of heat or cold, whether variable or constant,
as prevailing in the lower strata of the gaseous ocean of our planet.
ARABLE LAND.
A more useful picture than that of the isogeothermal lines would be
one of all the arable land covering the continents of the Old World
and the New,--indicating the composition of this nutritive earth, the
nature of the soil on which it reposes, as well as the various kinds
of cultivation appropriate in different climates. Here is a work to
be achieved,--a work which would benefit the whole human race,--a
work differing vastly from the conquests and achievements of too many
of those "heroes" the world delights to honour.
"Peace hath her victories
More renowned than war."
In this immense task, of which, as yet, not even the outlines have
been sketched, particular attention would require to be paid to the
_subsoil_; for upon this the success of all cultivation literally
depends.
[Illustration: FIG. 69.--_a_, Humus, or stratum of arable earth,--the
horizontal line shows the depth reached by the labourer; _b_,
subsoil; _c_, subsoil; _d_, arable earth; _e_, humus in an inclined
stratum; _f_, humus mixed with subsoil.]
Arable land is the most superficial stratum of the cultivable
terrestrial crust; it is this which the plough turns up and
subdues; it is this which, properly manured, and enriched by the
decomposition of organic matter, furnishes to vegetables their
principal nourishment. As it varies in thickness, it necessarily
presents one or other of the following circumstances:--1st, The
labourer, penetrating the entire stratum of arable earth (Fig. 69,
_a_), will strike down to the subsoil (Fig. 69, _b_); or, 2d, he will
not traverse the entire stratum (Fig. 69, _c_); or, 3d, after having
traversed the entire depth of the humus, he will reach a portion of
the subsoil (Fig. 69, _d_); or, 4th, after having gone through both
humus and subsoil, he will discover another layer of arable earth,
which may be either pure humus, in a thick inclined stratum (Fig. 69,
_e_), or humus mixed with the débris of the subsoil.
As for the subsoil, it may, by its composition, completely modify,
stimulate, or delay the action of the vegetable mould, however rich
this may be in assimilating principles. Thus, where the subsoil is
argillaceous, the pluvial waters are arrested by it as by a bed of
impervious cement, and render the ground too damp and cold to yield
abundant harvests. In such a case subsoil-drainage is the best
remedy. But if the earth be porous, the moisture gradually percolates
through its various layers, fertilising and warming, communicating
to the plants the needful humidity, and assisting in the production
of that most glorious of all the scenes of cultivated nature--a
corn-field thickly ripe with golden grain. In the poet's "Palace of
Art" no finer picture can be seen than this:
"The reapers at their sultry toil.
In front they bind the sheaves. Behind
Are realms of upland, prodigal in oil,
And hoary to the wind."
Oh! a sight to thank God for, and rejoice in, is the field all aglow
with the splendour of the harvest!
[Illustration: FIG. 70.--"Behind are realms of upland."]
Without having recourse to chemical analysis, which is within the
reach of a very limited number of persons, _clayey_ soils may be
distinguished by the vegetable species that most commonly flourish in
them: as--
I. _Plants belonging to clayey soils._--The Queen of the
Meadows, _Spiræa ulmaria_ (order _Rosaceæ_). Wild Angelica,
_Angelica sylvestris_. Common Sorrel, _Rumex acetosa_ (order
_Polygonaceæ_), and various kinds of Ranunculaceæ, as _Ranunculus
lingua_, _Ranunculus flamma_, and _Ranunculus sceleratus_.
II. _Plants belonging to sandy soils._--Horny Lotus, _Lotus
corniculatus_ (order _Rhamnaceæ_). Little Harebell, _Campanula
rotundifolia_ (order _Campanulaceæ_). Eyebright, _Euphrasia
officinalis_ (order _Scrophulariaceæ_). _Anthoxanthum odoratum._
III. _Plants belonging to argilo-calcareous soils._--Coltsfoot,
_Tussilago farfara_ (order _Compositæ_). Wild Mustard, _Sinapis
arvensis_ (order _Cruciferæ_). Buckwheat, _Polygonum aviculare_
(order _Polygonaceæ_).
IV. _Plants belonging to a sandy and calcareous soil._--Broom,
_Genista scoparia_ (order _Leguminosæ_). Centaury, _Centaurea
nigra_ (order _Gentianaceæ_). _Galium verum_ (order _Rubiaceæ_).
The Jacobea, _Seneecio Jacobæa_.
V. _Plants belonging to alluvial and marshy soils._--Reed,
_Arundo phragmites_, _Poa aquatica_, _Poa fluitans_. Rush,
_Juncus conglomeratus_ (order _Juncaceæ_).
After these different soils have been brought under cultivation, the
characteristic species, which we have just enumerated, disappear,
and are replaced by other plants, which grow, to all appearance,
spontaneously, under the name of _weeds_; but, in reality, spring
from germs or seeds too frequently mixed up with the different
manures, or spread abroad by the agency of birds or the wind.
In reference to this latter consideration, the diffusion of plants,
we shall transcribe an interesting passage from Balfour's excellent
"Manual of Botany."
"Some plants," he remarks, "are disseminated generally over the
globe, while others are confined within narrow limits. Some of the
common weeds in Britain, such as chickweed, shepherd's purse, and
groundsel, are found at the southern extremity of South America.
_Laura minor_ and _trisulca_, _Convolvulus sepium_, _Phragmites
communis_, _Cedium Mariscus_, _Scirpus lacustris_, _Juncus effusus_,
and _Solanum nigrum_, are said to be common to Great Britain and New
Holland. _Nasturtium officinale_, and _Samolus Valerandi_ are very
extensively diffused, and they may be reckoned true cosmopolites.
They are both natives of Europe, and they occur, the former near
Rio Janeiro, the latter at St Vincent. _The lower the degree of
development, the greater seems to be the range._ Some cryptogamic
plants, as _Lecanora subfusca_, are found all over the globe.
"Man has been instrumental in widely distributing culinary
vegetables, such as the potato, and the cereal grains, as well as
many other plants useful for food and manufacture. Corn plants,
such as barley, oats, rye, wheat, spelt, rice, maize, and millet,
are so generally cultivated over the globe, that almost all trace
is lost of their native country. They can arrive at perfection in a
great variety of circumstances, and they have thus probably a wider
geographical range than any other kind of plants.
"As regards these plants, the globe may be divided into _five_ grand
regions--the region of _rice_, which may be said to support the
greatest number of the human race; the region of _maize_; of _wheat_;
of _rye_; and lastly, of _barley_ and _oats_. The first three are the
most extensive, and maize has the greatest range of temperature.
[Illustration: FIG. 71.--The Rye District.]
"The grains extending farthest north in Europe are barley and oats.
Rye is the next, and is the prevailing grain in Sweden and Norway,
and all the lands bordering on the Baltic, the North of Germany, and
part of Siberia. Wheat follows rye; it is cultivated in the middle
and South of France, England, part of Scotland, part of Germany,
Hungary, Crimea, and the Caucasus. We next come to a district where
wheat still abounds, but no longer exclusively furnishes bread,--rice
and maize becoming frequent. To this zone belong Portugal, Spain,
part of France, Italy, and Greece, Persia, Northern India, Arabia,
Egypt, the Canary Islands, &c. Wheat can be reared wherever the mean
temperature of the whole year is not under 37° or 39° F., and the
mean summer heat, for a period of at least three or four months, is
above 55°. It succeeds best on the limits of the sub-tropical region.
In the Scandinavian peninsula, the cultivation of barley extends to
70° N. latitude, rye to 67°, and oats to 65°. The cultivation of rice
prevails in Eastern and Southern Asia, and it is a common article
of subsistence in various countries bordering on the Mediterranean.
Maize succeeds best in the hottest and dampest parts of tropical
climates. It may be reared as far as 40° N. and S. latitude on the
American continent, on the western side; while in Europe it can grow
even to 50° or 52° of latitude. It is now cultivated in all regions
in the tropical and temperate zones which are colonised by Europeans.
Millet of different kinds is met with in the hottest parts of Africa,
in the South of Europe, in Asia Minor, and in the East Indies."[80]
Professor Houston furnishes the following table in illustration of
the distribution of _wheat_ and _barley_. It also shows the mean
temperature which they require:--
BARLEY.
Winter Summer Annual
Mean. Mean. Mean.
N. Lat. 62-1/2° Faroe, 39° 51° 45°
70 Lapland, 22 46 33
67·30' Russia, 9 46 32
57·30' Siberia, 0 60 32
WHEAT.
Winter Summer Annual
Mean. Mean. Mean.
Lat. 58° Scotland, 36° 57° 64°
Norway, 23 59 39
Sweden, 23 59 39
Russia, 15 60 37
30° Cairo, 57 88 72
Macao, 64 82 73
Rio Janeiro, 68 78 74
Havannah, 71 82 77
Bourbon, 71 80 77
"Winds, water, and animals, are also instrumental in disseminating
plants. Many seeds, with winged and feathery appendages, are easily
wafted about; others are carried by rivers and streams, and some can
be transported by the ocean currents to a great distance, with their
generating powers unimpaired."
MUSHROOMS OR AGARICS (_Order_ FUNGI).
Every year--principally in autumn--we are startled by hearing or
reading of cases of poisoning by mushrooms. Erudite connoisseurs,
however, who have profited by Dr Badham's book on "Esculent Fungi,"
do not suffer themselves to be intimidated by these sad narratives,
though, unfortunately, they are frequently too well founded; because
they know how to distinguish the good from the ill, the true from
the false, the edible from the poisonous mushroom. But this security
ought not to embolden the inexperienced amateur in risking his
life for the sake of a delicacy. It is true, nevertheless, that we
frequently see men's lives exposed for something less.
"Look, what a splendid mushroom I have discovered!" a lady said to
me, the other day; a lady who knew something of flowers, but nothing
of _cryptogams_. "Take care!" I replied, taking from her hand the
supposed prize; "this is the false mushroom; and would suffice, if
served up at your table, to poison yourself and all your guests."
I ought here to observe that my friend had narrowly escaped death
two years before, through regaling herself with a dish of mushrooms
of very dubious character. Among the symptoms which she experienced,
and which she described with medical exactness, she particularly
dwelt upon the cold sweats, accompanied by a sentiment of undefinable
terror, which is nothing else than the dread of death: it was the
special symptom of poisoning with an unwholesome fungus.
Let us endeavour to make ourselves better acquainted with this
formidable enemy of epicures. You will have no difficulty in finding
it in any warm, close season, but especially in spring and autumn.
The toadstool thrives indifferently in the shade of all the forest
trees, but seems to prefer the oak and birch to the pine and fir.
A patch of soft greensward, at the foot of an old oak, and in the
neighbourhood of a "brawling stream" or "tranquil pool," will
generally be covered with fungi of this description. The numerous
synonyms attaching to it show how greatly it has exercised the
_classifying spirit_ of our naturalists. Some call it _Agaricus
muscarius_, as if we should say "kill-fly mushroom;" others,
changing only the specific designation, designate it _Agaricus
pseudo-aurantiacus_,--which signifies, literally, "false orange," in
allusion to the beautiful yellow colour of the _true_ aurantiacus.
What is certain is, that our mushroom, which can kill men as well as
flies, belongs to the genus _Agaric_, so numerous in species that it
can be formed into a family, that of the _Agariceæ_. The Agarics, of
which the esculent mushroom (_Agaricus edulis_) represents the type,
are easily recognised by their more or less fleshy _pileus_, or cap,
garnished underneath with _lamellæ_, or gills, which radiate from the
centre to the circumference, when the pedicel is in the centre.
[Illustration: FIG. 72.--"At the foot of an old oak."]
But some cryptogamists are unwilling to recognise the _orange
mushrooms_ (_les oronges_), whether true or false, as Agarics. They
place them in a separate genus, the genus _Amanita_, though without
informing us where they found the name. Meanwhile, they justify the
formation of the new genus by the presence of the white swelling,
the _volva_, or wrapper, of the _mycelium_, or spawn, which entirely
covers both the true and the false mushroom on its emergence from the
earth. Each, then, is an _Amanita_. But now remark their specific
difference. The true mushroom, as it develops, ruptures its ovoid
wrapper, or volva, leaving the remains entirely at the base of the
pedicel; while, in the false mushroom, the débris of the volva are
formed, not only at the base of the pedicel, as in the real Agaric,
but even upon the red surface of the pileus itself: these are the
white irregular warts characteristic of the Amanita, but wholly
wanting in the Agaricus. Thus, there are two Amanitas: the _Amanita
muscaria_, or "fly agaric," and the _Amanita aurantiaca_, or, as the
English botanists call it, _Agaricus Cæsareus_, the imperial mushroom.
This fanciful "study" in nomenclature has the advantage of initiating
us into the most essential distinctive characters of the two species
in question. However, a few additional details are necessary to
complete our history.
THE FLY AGARIC, OR AMANITA MUSCARIA.
The species seems to have been expressly created to teach our
gourmands the necessity of vigilance; that before enjoying a dainty
they must first learn to distinguish, under penalty of death, the
poisonous fungus from that which safely and pleasantly tickles
the palate. The warning is useful, moreover, as showing that even
sensualists are not wholly exempt from the law of work.
The _Amanita_, like most falsehoods, is pleasant to the sight. Its
round pileus, of a beautiful orange-red colour, spotted with white
warts, and lined with white gills, seems to invite your attention.
(Fig. 73.) Strike it down with your stick; the lamellæ or gills
underneath resemble the white leaves of a book. Its graceful stalk,
ornamented on the upper part by a well-designed necklet, is bulbous
in its lower portion; its flesh is dazzlingly white; in short, its
entire appearance is attractive. Yet it is a traitor! You little know
the depth of its wickedness. Mix a few shreds of its white flesh with
a little milk; every fly which drinks of the mixture will, in a few
seconds, fall dead, their swollen abdomen bearing testimony to the
effect of the poison. And in many districts of Germany, particularly
in Thuringia, the peasants make use of it to rid themselves of the
swarms of flies which, towards the close of summer, infest their
habitations. It is thus that man may frequently turn to his advantage
those objects of nature which, at the first glance, appear injurious
rather than useful.
[Illustration: FIG. 73.--The _Amanita Muscaria_.]
Various experiments have been essayed to test the intoxicating
influence of our _Amanita_. Bulliard, author of the "Histoire des
Champignons de France," made two cats partake of it. Six hours
afterwards, these animals, who are so tenacious of life, were dead.
Haller, in his "Histoire des Plantes Vénéneuses de la Suisse," says
that "the _Agaricus muscarius_ (_Amanita muscaria_) cannot be eaten
with impunity, six Lithuanians having died of it; and in Kamtschatka
it has been known to excite deadly attacks of delirium, accompanied
by so deep a despondency, that those who have eaten of it would
fain fling themselves into the fire, or fall upon their knives or
daggers." This, however, we take to be an exaggeration. The truth
is, that in Kamtschatka it is used to produce intoxication; and such
is its strength, it imparts an intoxicating property to the urine
of those who swallow it. When the fungus itself is not at hand, the
would-be drunkard frequently resorts to this nauseous potion.