The body elongated, cylindrical, garnished with long setiform hairs, and composed of eight segments, six of which are perfectly distinct, and two (the two latter) very short, and scarcely perceptible; four-jointed antennæ, longer than the head; long, slender, cylindrical feet; forked tail, silky, and transversely wrinkled; seven eyes, laterally grouped at the base of each antenna; body without scales.

The Desoria glacialis, a species at present unique, is of a velvety black, and about one-sixth of an inch in length.

The Podura plumbea (or "Spring Tail"), common enough in England, and found under all kinds of stones, will give the reader an idea of the flea of the glaciers.

On comparing these two species, we remark, first, that the Podura plumbea is somewhat longer and thicker in body than the flea of the glaciers (see Fig. 16; a, natural size; b, enlarged); but it is more particularly by the length of its antennæ that we distinguish it. It owes its specific name of Plumbea to the livid blue or leaden colour of the scales which cover its body. These scales resemble those of butterflies; only they are much smaller, more finely situated, and very variable in form and size (Fig. 17). In catching it great care is required, for it is so easily crushed; it is, besides, very soft to the touch, though, when examined with a microscope, it is seen to bristle all over with hairs, apparently very hard.

Our poduræ have also the faculty of leaping, and cling by thousands to humid places, especially to mosses and the under-surface of stones. The mechanism of their leap is explained by the presence of a forked, flexible, and elastic appendage, lodged in a kind of ventral groove beneath the last segments; by projecting this rapidly behind, the whole body of the animal is thrown forward. At the slightest contact the insect folds up its caudal appendage under its belly, and you would then suppose it did not possess one. This circumstance explains why, in many books of natural history of good repute, the poduræ, and especially so common a species as the Podura plumbea, are represented without this characteristic instrument.

Herbaceous Plants which best endure the cold of Winter.

The "way to look at things," which is the true foundation of science, varies, not only according to a man's degree of intellectual cultivation, but according to his social condition or profession. The herborist has eyes only for the plants in which he deals,—the "simples" which, as we read in old Gerarde, wrought such wonderful cures in the days of our forefathers,—and from the most exquisite flowers he turns with indifference. The gardener, on the other hand, is wholly absorbed by his love and his hate,—his charming exotics, and his troublesome weeds. The latter he regards with much the same feelings as a society wholly composed of honest men would regard an infusion of the "dangerous elements;" for weeds, like rogues, take what is not their own, and deprive others of their means of sustenance. But to classify plants according to their virtues or vices is not worthy of science, exclaims the rigid botanist. Would you mingle vile self-interest with the pure study of the vegetable kingdom? Remember that all selfish feelings ought to be banished from the sublime sanctuary of analysis and synthesis.

This sounds exceedingly well. Disinterested words, from whatever quarter they come, always produce—perhaps, on account of their comparative rarity—an admirable effect. But what is their real value? To ascertain it, the listener must be able to seize, like so many luminous threads, all the emotions which are acting upon the heart and tongue of the speaker. But we are very far from having arrived at this degree of perfection. Shall we ever attain to it? Yes, because we can conceive its possibility. But, until that golden epoch, the pure love of science will always remain a myth, and we shall not have universally understood the necessity of seeking in the profound study of nature the grand destiny of man.

It is among the weeds and noxious plants that we shall find the species capable of enduring longest the cold of winter. What part, then, do they fulfil in the economy of creation? An ambitious, but not a novel question, which has often been propounded in reference to our parasitical insects.

The best answer which we can make to it is this: Everything invites us to work. Labour is imposed even upon him who least desires it. Earth will yield a return only in proportion to the care we bestow upon her.

If, after having toiled and sown, we had nothing to do but to gather in the harvest, every person would become an agriculturist. But a soil which is not manured will soon grow exhausted; and if it be neither ploughed nor harrowed, instead of barley or vegetables, it will soon be covered with tares; rank weeds will flourish in every field. Such is the chastisement reserved for sloth,—the true "original sin" of the human race.

Well, then, it is among the weeds, everywhere so common, that we meet with the plants best able to brave the rigours of frost.

The Dog Mercury.

The annual Dog Mercury (Mercurialis annua) is one of the most tenacious. It attracts the passer-by, if he condescend to bestow a glance upon it, only by its extreme abundance; it propagates very largely, though it is by no means partial to all localities. For instance, it avoids the woods as persistently as its congener, the common Dog Mercury (Mercurialis perennis) seeks them. It prefers the vicinity of human habitations and uncultivated fields. If let alone, it spreads with a dangerous rapidity, and invades every garden which is not kept in the most exquisite order. Still, we must not deal too harshly with it. It is not altogether unfriendly to man. In truth, owing to its laxative properties, it renders him invaluable services. The country people have great faith in fomentations of Dog Mercury and honey. Understand, we pray you, that not an atom of mercury enters into it, despite its significant name; but a decoction of the annual Dog Mercury, mixed with a little thick honey, answers all the purposes of those lenitive clysters which are so beneficial to excitable temperaments. The leaves of the plant are eaten in Germany like spinach.

Of the Mercurialis perennis Mr Sowerby writes:—"This plant was formerly used in medicine, but has long been abandoned as a remedy. It is extremely acrid, and even poisonous, though recommended in some old books as a good pot-herb, probably from being confounded with the annual species. When steeped in water, the leaves give out a fine blue colour resembling indigo. This colouring matter is turned red by acids, and destroyed by alkalis, but is otherwise permanent; it might possibly prove valuable as a dye, if any means could be discovered of fixing it, and the herb has been introduced into this work with the view of drawing the attention of chemists to the subject; no experiments seem to have been lately made upon it."

Let us now advise you how to distinguish our medicinal plant from the "ill weeds" with which it loves to associate. Its ovate, rough, irregularly-dentated, and petiolated leaves would not give it a sufficiently marked character, had it no other features peculiar to itself. But observe the yellowish-green glomerules, arranged, like millet, on a long frail spike. (Fig. 18, a.) They exhale, as your nose will inform you, a peculiar aroma, like that of spiced bread: no other plant but our Dog Mercury is gifted with this odour. Now, bring your magnifying-glass to bear upon it; with the point of a knife or a feather open one of the grains which form the glomerules of the spike; out of it will leap, as if impelled by an invisible spring, a large number of stamens, easily distinguished by their elastic thread-like anthers, covered with tiny yellow beads. Each greenish grain is a flower; the calyx, which also serves as the corolla, is represented by three little petals, forming the external envelope of the little flower. (Fig. 18, b.) But something essential is still wanting; in the centre of the stamens you do not find any pistil. Why is so important an organ wanting? Because our little rounded flowers, with their spice-bread odour, have but one sex, are unisexual; they are male flowers, since they are furnished only with stamens. In vain do you hunt on the same stem for their companions, the female flowers. You will find them only upon other stems, distinct from those which bear the male flowers. The Dog Mercury, then, is a plant whose two sexes are lodged in two different houses, οἴκοι—is, in fact, a dioecious species.

But you are sure to find the female flowers in the immediate neighbourhood of the stems with the male flowers. They are easily recognised by their larger and darker leaves (Fig. 18, c); and especially by their little twin pods, green, wrinkled, and pedicellate,[24] which garnish the axil of the leaves. (Fig. 18, d.) From this characteristic the female mercury was formerly mistaken for the male; and many centuries elapsed before naturalists recognised, what now-a-days seems so simple, that the little pods, joined in couples, and containing each a grain, composed the fruit of a single plant; that every fruit proceeds from an ovary; and that every ovary is a sign of the feminine sex.

In the Historia Naturalis of Pliny, who was at once so acute and so credulous an observer, we first meet with the name of Mercurialis.

"The plant is so denominated," he says,[25] "because it was discovered by Mercury. Its juice, mingled with that of the hibiscus (a species of the Malvaceæ) and the purslain, forms a kind of unguent, with which, if you thoroughly rub the hands, they can touch molten lead without being injured."

The description which Dioscorides[26] gives of the Linozosis, which he also calls Parthenion, or Mercury's Plant (Ἑρμου βοτάνιον) applies, in the main, to our Dog Mercury. It is true that its leaves "are not like those of the basilic" (φίλλα ὄμοια ὁκίμῳ); but they resemble in all respects those of the smooth variety of cultivated mint; and, apparently, the basilic of Dioscorides was one of our mints. The fruit of the female, he adds,—evidently meaning the male flowers,—are disposed in clusters.

Both species of the Herb or Dog Mercury belong to the family Euphorbiaceæ.

Our attention must now be directed to another point. It is a fact, that in winters of moderate severity the Mercury continues to infest our gardens and cultivated fields. It only succumbs to a frost equal to six to ten degrees below freezing-point; then its congealed stem totters, and grows black, and its leaves mingle so completely with the soil that it is difficult to discover any vestiges.

How singular a contrast! The plants most destructive in our kitchen gardens are frequently the most useful in medicine. There are no drugs more popular than the weeds which we call Herb Mercury, Garden Nightshade, and Dog's-tooth grass. All belong to families whose properties are strongly marked. As already stated, the Mercury ranks among the Euphorbiaceæ, remarkable for their acrid and more or less purgative juice. In this family occur the most violent drastics, such as the Croton tiglium, whose oil (expressed from the seeds) has long been considered an efficacious medicine. The Garden Nightshade is one of the Solanaceæ, and cousin-german of the useful potato; and the Dog's-tooth grass, whose roots compose three-fourths of our possets, is of the same family as our cereals.

The Garden Nightshade.

If you have seen—and who has not?—the flowers of the potato-plant, you will immediately recognise the flowers of the Garden or Black Nightshade. (Fig. 19.) This noxious herb—noxious in some, but useful in other respects, and, therefore, not to be visited with too hasty a condemnation—flowers and fructifies throughout the year. Its fertility is extreme; only the severest winter-frosts can crush out its prolific life. The fruits which succeed to the flowers are smaller berries or "apples" than those of the potato. (See Fig. 20.)

In the history of botany, and even in that of philosophy, the Black Nightshade (Solanum nigrum) has a certain interest. Thus, says M. Hoefer, both Cordus and Jean Bauhin, botanists of the sixteenth century, have described the flower of this plant as if its corolla were composed of five distinct petals.

Where were the eyes of those great botanists? The corolla of the nightshade, like that of all the Solanaceæ, is plainly and obviously monopetalous,—that is, composed of a single piece; to assure yourself of this, you have but to open it out. (See Fig. 21, b.) It was the sharp-pointed, ovate divisions of the limb which imposed on the old observers; a fresh proof that seeing and observing are two very distinct things. Our vision enters into full exercise from earliest infancy; observation is not acquired until after much labour and many years.

Do not forget to add, that the five stamens are brought very closely together by their elongated anthers, as is also seen in the flower of the potato-plant. (Fig. 21, a.)

The same botanists who took our solanum for a plant with a polypetalous corolla, considered the Bitter-sweet (Solanum dulcamara) to be a metamorphosis of the Garden Nightshade! The former they christened the red-berried solanum (Solanum baccis rubris), and the latter, the black-berried solanum (Solanum baccis nigris).

But if we once launch into the hypothetical, we shall be unable to stop half-way. If the species of one and the same genus are the result of a transformation, why may we not assert as much of the genera of a family, or the families of an order?

Thus we should arrive, step by step, at an unique type, not only for the vegetable kingdom, but for vegetables and animals, including man himself, and realise, to some extent, the ideal of the Greeks,—unity in variety.

Be it acknowledged, however, that we have no desire to rise to so lofty an elevation. The potato-plant—unknown to the ancients, inasmuch as it is a native of the New World—has not been found to lose its character since its introduction into the ancient continent; its congener, the nightshade—an old native, like every bad herb—accompanies it everywhere; but its fibrous roots are absolutely virgin of every farinaceous tubercule.

Though the nightshade is common everywhere, Tournefort was the first to describe it with complete accuracy. That great observer even specifies various peculiarities which most of our botanists omit from their descriptions. Thus, he rightly remarks, that the peduncles branch out so as to form a kind of umbel, and do not emerge, as is usually the case, from the axils of the leaves, but a little below, from the very branches of the stem. He was also the first to note—and it was a veritable discovery—that the white flowers of the nightshade, grouped in threes to eights, are each formed of a single cup-shaped leaf,—in other words, that the corolla is monophyllous, and slightly bell-like or campanulated. Nor does he forget to describe the disposition of the five stamens, set close around the pistil, which, as it develops, forms a globular bacciform fruit, embraced by a five-lobed calyx. This fruit, which changes in colour from green to black, is filled with a great number of grains in a thick liquid, exhaling a nauseous odour. As for the leaves, they resemble those of spinach, for which, in some countries, they serve as a substitute.

Like all plants found by the wayside, and among heaps of refuse, the nightshade loves to vary its form, and of its various forms some nomenclators have made as many different species. The typical variety, the Solanum nigrum, has glabrous stems and leaves, that is, they are covered with short, but hardly visible hairs; its berries are black.

The smooth variety, or Solanum villosum, is rather rare, and has swollen or bulging leaves and stems; its berries are red or of a reddish yellow. The two varieties seem able, by sowing, to be transformed into one another. A sub-variety of the Solanum villosum has been described as a peculiar species, under the name of Solanum miniatum, so named on account of its vermilion-coloured berries. The Solanum ochroleucum and Solanum luteovirens, the first with yellowish, and the second with greenish berries, are simply varieties, and the same may be said of the dwarf form, known by the name of Solanum humile.

But the physician is more interested in the solanum than either the gardener or botanist. For him it is no useless or noxious weed, but, on the contrary, is an eminently precious herb. And, in fact, if it possessed only one-half the virtues formerly attributed to it, we ought to bow to the ground every time we encounter it.

Listen to our authorities even if you do not respect them.

Cæsalpin asserts that the decoction or juice of the nightshade is a sovereign remedy for complaints of the stomach and the bladder, and regards nightshade-water, mixed with an equal quantity of absinthe-water, as one of the best sudorifics.

Tragus, a physician and botanist like Cæsalpin, recommends the juice of the nightshade as anti-choleraic, as well as efficacious in inflammation of the liver and stomach. And yet, at the same time, he grows emphatic in reference to its poisonous properties. "Do not," he says, "employ this herb immoderately, lest it should happen to you as, in 1541, I saw it happen to an inhabitant of Erbach, near Hohenburg. After having eaten a few nightshade-berries, he was seized, on the following day, by a furious monomania, which led his neighbours to believe him possessed of a devil. After having uselessly employed every kind of exorcism, they sent for me. I made my patient swallow some very strong wine; he fell into a profound slumber; and, when he awoke, was cured."[27]

Withering affirms that a couple of grains of the dried leaves will act as a powerful sudorific, and that they have also been found useful in some cutaneous disorders.

Here is another authority, before whom naturalists are accustomed to give way. We make use of the Solanum nigrum, says Tournefort,[28] when it is necessary to subdue inflammation, or soften and relax the fibres. The pounded herb is applied to hæmorrhoids. The juice, with a sixth-part of rectified spirit-of-wine, is advantageous in cases of erysipelas, ringworm, wildfire, and all diseases of the skin. Nightshade is also employed in anodyne cataplasms.

Tournefort did not confine himself to simple botanical descriptions; he did, what our modern botanists neglect doing,—he made experiments, both physiological and chemical, on the plants employed in medicine. Thus, he began by tasting the different parts of the plant.

"The root," he says, "is almost insipid; the leaves taste like a saltish herb; there is something sharp and vinegary in the fruit; the whole plant has a narcotic odour. The leaves do not redden turnsole,[29] but the ripe fruit reddens it greatly; whence we may conjecture that the sal-ammoniac contained in this plant is moderated in the leaves by a very considerable portion of fœtid oil and earth, but that the acid portion of the salt is strongly developed in the ripe fruit; so that we must choose our part of the plant according to the purposes we wish to employ it for. The fruits, for instance, are more refreshing, but more repellant, than the leaves, which soften while resolving, cleansing, and absorbing."

We admit that these data leave much to be desired from a chemical point of view. We may well ask, for example, how the illustrious philosopher ascertained the presence of sal-ammoniac in nightshade? But it is not fair to criticise the science of the past, by judging it through the deceitful prism of the science of to-day. We must adopt the methods of our predecessors, when discussing natural productions from all the view-points of their applications.

Dog's-tooth Grass.

In clearing an uncultivated field we uproot a great number of herbaceous plants of different families; but those of the Gramineæ, or Grasses, invariably predominate. They are the trailing roots, or rhizomes, of certain species which have been included under the general denomination of Dog's-tooth. These tenacious and vigorous roots,—so wholesome in various maladies, so injurious to cultivation,—are, whatever certain botanists may say, far from tracing their origin in all cases to the Triticum repens (couch-grass) and Panicum dactylon—those terrible enemies of the corn-field, which, once established in the soil, are with difficulty extirpated, and prove very injurious to the "golden crops." Nearly every grass which puts forth rhizomes will furnish the Dogs-tooth. We may cite, for instance, several species of Festuca (as Festuca rubra and Festuca pinnata), or fescue grass; at least two kinds of meadow grass (Poa compressa and Poa pratensis), a species of wild-oats (Avena elatior), to say nothing of the weeds Arundo phragmites and Arundo epigeios. The long rhizomes of these vivacious plants possess nearly the same properties, due to their saccharine principles.

How shall we distinguish these plants from one another? Their leaves have almost exactly the same configuration; they are linear;[30] and their flowers are not apparent,—they do not attract the gaze of the passer-by. Yet they possess all the organs necessary for the reproduction of their species:—three stamens, each composed of an anther and a characteristic filament; on this anther, whose two lobes are arranged like the branches of an X, the pistil softly and tenderly balances itself on the summit of a frail thread, to which it is attached by the back. Remark, too, the two styles with feathery stigmata,[31] like the barbs of feathers. Nothing is wanting to constitute a complete flower.

There is even a perianth, or calyx, represented by a couple of tiny membraneous scales, scientifically known as glumellulæ; then at the base of each spikelet, composed of one or two of these bright green lilliputian flowers, are two other and larger scales, called glumellæ: they represent an involucre.[32] It is almost unnecessary to add, that the free, unilocular ovary, or seed vessel, forms, as a result of its development, the seed, whose embryo adheres laterally to a farinaceous kernel, or perisperm. The union of one or more of these flowers composes a spikelet, and the union of the spikelets constitutes the spike, which may be disposed on a simple or ramified axis. Such are, in general, the characters we must keep before us in the difficult study of the Gramineæ.

Let us now see, more closely, the two plants which, according to the botanists, furnish the root of the Dog's-tooth.

When walking along the sandy bank of a river, you must frequently have trodden under foot a low, almost crawling herb, remarkable for its violet-red spikes, which, three to five in number, are arranged like the fingers of a hand, on the summit of a short curving stem.

This glaucous-leaved herb is the Panicum dactylon (i.e., fingered-millet) of Linnæus. The long trailing rhizomes, joined to some less prominent characters, have been sufficient for some botanists to create a special genus, Cynodon, or Kynodon (a Greek word, signifying literally "Dog's-tooth"), and to change the Linnean denomination of our grass into Cynodon dactylon. It is seldom met with in cultivated land; but in such a locality as we have already described, and sometimes on open sandy shores, where the summer sea comes with a gentle ripple and a subdued music, it may frequently be found. Its long, tough runners creep through and over the loose soil for many yards, rooting at every joint, and furnished with flat, rather short leaves, of a glaucous hue. The flowers grow in narrow, linear spikes, arranged at the top of a short leafy stem in the form of an umbel, and give the grass, when in bloom, a very peculiar and characteristic aspect.

But if the Cynodon dactylon is rare in cultivated fields, the Triticum repens—commonly called couch-grass, but, in our opinion, the true and genuine dog's-tooth—is particularly abundant. (See Fig. 23.) Its long subterranean stems increase with astonishing rapidity, and if the smallest fragment be left in the soil, it will vegetate, and speedily extend itself, until it becomes almost impossible to extirpate it. It is a kind of wild barley, with stiff leaves of a moderate length, and of a bluish tint, and a double spike, composed of clusters of four to six flowers, each crowned by a narrow ridge. We must not confound the Triticum repens with the Elymus caninus of Linnæus, which has no trailing underground roots like the former. It differs also from the latter in the roughness of each side of its leaves,—only one side of the leaf of the Triticum repens being rough,—and in the crests which rise above the flowers.

Was the dog's-tooth known to the ancients? Undoubtedly, for the dog's-tooth flourishes in all climates,—is truly cosmopolitan. But it is difficult to decide whether their Agrostis and their Gramen apply to the above-mentioned species.

According to Diodorus, the primitive Egyptians lived upon herbs. "They also eat," he says,[33] "the stems and roots which grow in the marshes. Especially did they hunt after the Agrostis, a plant remarkable for its sweet savour and the sufficient nourishment which it offers to the wants of man. It is likewise considered an excellent provision for cattle, from its fattening properties. It is in remembrance of these benefits that the inhabitants of Egypt, when worshipping their gods, carry this plant in their hand."

The Agrostis of Diodorus would apply to all the Graminaceæ whose stems and roots contain nutritive and saccharine principles. Let us here remind the reader that the sugar-cane belongs to the same family as barley and the dog's-tooth.

Pliny is much more explicit. What he says of the Gramen (or grass), the "commonest of herbs"—inter herbas vulgatissimum—and of the geniculated spaces between its knots (geniculatis serpit internodiis), applies with tolerable accuracy to our Triticum repens. He also speaks of the diuretic properties of a decoction from its trailing roots.[34] As for his Gramen aculeatum (or needle-like grass), it is positively our Cynodon dactylon. "The five spurs or needles which shoot out," he says, "from the top of the stem, have procured it the name of Dactylon." To these digitiform spikes he attributes the property of checking the bleeding of the nose, when they are introduced into the nostrils. But a thorn is much better fitted to produce this effect; the spikes of the digitated panicle of the Cynodon dactylon are much too soft to determine epistaxis by a mechanical action. So it is not improbable that they owe their putative virtue to their colouring, which is not unlike that of blood, and which has even procured for the species the name of Digitaria sanguinalis. In the same manner the capricious mediæval imagination pronounced liverwort, with its marbled leaves, a sovereign remedy for diseases of the lungs,—organs remarkable for their marbled appearance.

Dioscorides is quite as explicit as Pliny. What the latter names Gramen, he, however, calls Agrostis. After having particularised the nodosities of the stem—a feature common to nearly all the Graminaceæ—he describes very clearly the long creeping roots put forth by the said stem; and he does not forget to mention the sugary savour, so characteristic of the rhizomes (ῥίζας γλυκείας) of the Triticum repens.[35] Theophrastus confines himself to indicating the Agrostis as a herb which infests the fields.[36]

The Cynodon dactylon is, at the present day, very common in Greece, where it is specially partial to low grounds, which are somewhat damp and sandy. The inhabitants call it Agriada, a name derived from ἄγριος, "wild." But if we may believe Fraas, the author of a Flora Classica, the genuine dog's-tooth, Triticum repens, is, on the contrary, very rare in the land of Socrates. This is a curious fact, if a fact, for geographical botany.

Throughout the Middle Ages, and down to the eighteenth century, were confounded, under the generic name of Gramina, or grasses, the most diversely-featured herbs, including the dog's-tooth. Tabernæmontanus, Dodonné, Mathiole, Jean and Gaspard Bauhin, were the first to attempt the clearing of a path through this intricate wilderness. They eulogised, at the same time, the emollient properties of the dog's-tooth.

Tournefort[37] and Bernard de Jussieu, who appear to have made a chemical analysis of it, pretend that the roots of the dog's-tooth contain a large quantity of oil, earth, and several acid liquids, as well as a little fixed salt. "According to all appearance," they add, "the roots act by means of a salt analogous to salt of coral, enveloped in a great deal of sulphur."

Instead of mocking us with such fantastic analyses, which can only excite the laughter of our modern chemists, Tournefort and Bernard de Jussieu would have deserved better of science if they had applied themselves to the task of introducing light and order into the cloudy chaos of the Graminaceæ of the botanists of their age.

But winter is passing away, and the time for the singing of birds is at hand. Already the earth is awakening from her prolonged lethargy; the hedgerows are green with budding leaves; the purple crocuses shine in many a sheltered field; on bank and brae, in glen and vale, the glory of the primrose makes glad the heart of man; the wood anemone hangs its delicate head in the woodlands; and it seems as if a gladder feeling animated the universal nature.

And the heart and the brain and the soul sympathise in this apparent delight of material things; the heart beating more freely, the brain feeling a stronger working power, and the soul rising to purer views of life and its duties:—

CHAPTER I.
WHAT MAY BE SEEN IN THE HEAVENS.

I It may be doubted whether many of the patrons of Mudie's are acquainted with the works of a philosopher, who, in his day, enjoyed no little fame—I mean, Robert Boyle (1627-1691),—and yet there are passages in them well worth attentive perusal, from the lucidity of their style and the soundness of their reflections. He has, for instance, some observations in his "Considerations on the Usefulness of Experimental Philosophy," which are germane to the general purport and tone of our little book. He remarks, that the contemplation of the vastness, beauty, and regular motions of the heavenly bodies, the excellent structure of animals and plants, besides a multitude of other phenomena of nature, and the subserviency of most of these to man, ought, certainly, to induce him, as a rational creature, to conclude that this vast, beautiful, orderly, and, in a word, many ways admirable, system of things, that we call the world, was framed by an Author supremely powerful, wise, and good.

The works of God, he adds, are so worthy of their Author, that, besides the impresses of His wisdom and goodness that are left, as it were, upon their surfaces, there are a great many more curious and excellent tokens and effects of Divine artifice in the hidden and innermost recesses of them; and these are not to be discovered by the perfunctory looks of oscitant and unskilful beholders; but require, as well as deserve, the most attentive and prying inspection of inquisitive and well-instructed considerers. It is not by a slight survey, but by a diligent and skilful scrutiny of the works of God, that a man must be, by a rational and affective conviction, engaged to acknowledge, with the prophet, that the Author of nature is "wonderful in counsel, and excellent in working."

That He is wonderful in counsel and excellent in working must be the conclusion of every devout student of the celestial phenomena; and to those we shall, therefore, devote the first portion of our Spring meditations.

What reception would formerly have been given to any poet who had dared to exclaim—

Would he not have been met with the reproach which Horace, in his Ars Poetica, so epigrammatically formulates?—

As for men of science, they would not have condescended to honour even with a smile such strange and fantastic words.

Let us suppose, now, that our poetical astronomer, thus contemned, had addressed his scientific censors in some such language as the following:—

Do not think, illustrious sirs, that it is by a purely poetical licence I call the firmament a mirror in which the earth may be seen reflected. Only, to prevent all equivoque, we must understand one another. The mirror to which I am alluding does not reflect light, but movement. It is in a particular movement of the stars that the true figure of our planet is reflected, is revealed to us. But before the human mind can appreciate this movement,—especially before it can discover the cause,—we must be prepared to devote ourselves to centuries of assiduous effort. In this long interval, philosophers of every class will allow unrestricted scope to their imagination.

Shall we, then, recall some of these opinions,—some of these truly poetical licences?

Homer and Hesiod represented the earth as a disc, or as a flat rondel, surrounded on all sides by a winding river which they called the Ocean, and which, in the extreme East, communicated with the Phasis, in Colchis. Above this terrestrial disc the outspread sky was arched like a vast dome; a dome supported by two massive pillars, resting on the shoulders of the god Atlas.

Surely the ancient poets must have evolved the earth-disc from their own prolific imagination. Can they never have seen a far-off vessel, showing, as it approached them, at first the tops of its masts, then its swelling sails, and finally its hull? They might have made so simple an observation in any seaport; if they did, why did it not suggest to them the idea that the earth, instead of being level, must be round? Because it is easier to let the imagination speak than the reason.

The fiction of the earth-disc remained long unshaken, with the exception of a few modifications. Thales figured to himself the earth as floating on a humid element. And, six centuries later, we find Seneca still adopting the opinion of the Greek philosopher. "This humid element (humor)," he says, "which sustains the disc of the earth like a ship, may be, perhaps, the ocean, or a liquid of simpler nature than water."[38]

But how, then, was the rising or setting of the stars explained? The ancients supposed that they were extinguished at sunset, and rekindled at sunrise. Thus, an unfounded hypothesis has for its consequence a still more baseless hypothesis; and in this manner we glide down the slope of fiction to fall eventually into an abyss of contradictions. Such is the true punishment of error.

Let us continue.—According to the Chaldeans, who were thought to be profoundly versed in astronomy, the earth was hollow, and shaped like an egg-shell. And,—adds Diodorus, from whom we have this detail,—they adduce numerous and plausible proofs of this assertion.

Yet was this idea in direct opposition to the evidence of our senses when we travel over a wide plain, or navigate the great deep; at least, unless we admit that the earth has the form of a reversed egg-shell, with its convex face uppermost, and its concave one beneath. Heraclitus of Ephesus introduced the Chaldean doctrine into Greece.

Anaximander represents the earth as a cylinder, whose upper face alone is inhabited. This cylinder, adds the philosopher, is a third of its diameter in height, and floats freely in the midst of the celestial vault, because there is no reason why it should move more to one side than the other. Leucippus, Democritus, Heraclitus, and Anaxagoras,—names of high repute in the history of philosophy,—adopted Anaximander's system, though it was neither more nor less than a wild phantasy.

Anaximenes and Zenophanes, without pronouncing dogmatically on the form of the earth, represented it as resting,—the one upon compressed air, the other upon roots which were prolonged ad infinitum. But upon what was the compressed air supported? And of what nature were these mysterious roots?

Plato, with a nearer approximation to the probable, gave to the earth the form of a cube. The cube, bounded by six square equal surfaces, appeared to him the most perfect geometrical solid, and consequently the most suitable for the earth, supposed to be the centre of the universe.

Eudoxes, who, in his long travels in Greece and Egypt, must have seen new constellations rising in the south, while others disappeared in the north, never ventured to adduce from his astronomical observations the sphericity of the earth.

Aristotle, bolder than Eudoxes, was led to the conception of this sphericity by simple consideration of mechanics. The earth, he said, must be a sphere, because each particle of matter is carried, by gravity, towards the centre; and as this fact is general, the superficial particles must be at an equal distance from the centre. This theoretical view was adopted by Archimedes, who applied it to the waters covering the terrestrial surface. Aristotle went further; he saw the rotundity of the earth in the shadow thrown by the latter on the bright face of the moon during its eclipses.

It is a noteworthy fact that the arguments of Aristotle, founded on a method to which all the progress of science is due, remained unaccepted for two thousand years. And why?

We shall attempt to explain.

Among those subjects whose comprehension seems to have been specially difficult to the mind of man, we must include the fact that the earth floats without any solid support in the infinity of space, and carries its denizens on its surface, both above and below.

Our creeds, which have ever pretended to explain everything in the physical as well as in the moral order, have here endeavoured to come to the assistance of the weakness of the human mind. And as each creed asserts itself to be the best, to the exclusion of every other, men began to imagine for the earth a navel, and placed it where it was supposed pleasing to the divinity.

The Greek priests dismissed a couple of eagles, one towards the west, the other towards the east; the place where these favourite birds of Jove, of the "Father of gods and men," encountered each other, was to be considered the "navel" of the earth. It chanced to be Delphos, whose oracle was the most esteemed in the ancient world; the sacerdotal caste accumulated there immense wealth. The Greek priests prudently refrained from dealing with the difficult problem of the earth's solid support.

The Hebrew pontiffs, however, were not so reserved. After having made Jerusalem the "navel of the world," they allowed for the earth itself seven solid columns as a foundation. The question of the Antipodes, in which the greatest intellects of antiquity believed,—Pythagoras, Plato, and Aristotle,—was thus pontifically judged and condemned. And Christians who preferred to follow the Judaical observance of external ceremonies to a true comprehension of the spirit of the Gospels, exaggerated the application of this sentence.

The dogmatic condemnation of the existence of the Antipodes long arrested man in his search for that fourth quarter of the world whose inhabitants should have their feet directed towards ours. It was one of the principal obstacles which Columbus was called upon to surmount in the realisation of his sublime idea. When cited before the Council of Salamanca,—composed of prelates and men of science,—he had to meet the revived objection of Lactantius, a Christian apologist of the third century:[39]—"Can there be anything more absurd than a belief in the existence of Antipodes, of inhabitants with their feet opposite to our feet, of people who walk with their feet in the air, and their heads on the ground?—that there is a part of the world where everything is inverted, where trees throw out their branches from top to bottom, while it rains, and hails, and snows, from bottom to top?"

Columbus admirably demonstrated, from an artificial globe, that flies walked as easily on the lower as on the upper surface, and hence pointed out that men, compared with the size of the earth, are much smaller still than flies. But his judges persisted in their conviction, and did not fail to cast in his face the jesting words of Plutarch: "Philosophers, rather than renounce a favourite hypothesis, would make human beings crawl on the lower face of the earth like worms or lizards." But it was principally the authority of St Augustine which they invoked to condemn a belief in the Antipodes. St Augustine had declared such a belief incompatible with the dogmas of the faith; for to admit the existence of inhabitable lands, in the opposite hemisphere, would be to admit the existence of peoples not descended from Adam, since it would have been impossible for him to traverse the ocean lying between Asia and the Antipodes!

Some authorities denied the Antipodes on the ground taken by certain classic writers, that the regions of the opposite hemisphere were uninhabitable under the tropics, on account of the extreme heat, and near the Poles, on account of the extreme cold. Others cited Epicurus, affirming that the earth was inhabitable and roofed with a celestial vault only in our western hemisphere, the other half being an inaccessible chaos. Others pretended that no traveller could reach the east by way of the west, because the earth, being pear-shaped, he would encounter on his road an insurmountable tuberosity,—undoubtedly the tail or stalk of the pear! Finally, there were some who dwelt upon the magnitude of the earth, whose circuit would occupy a voyage of upwards of three years.

It was to this objection, as the most serious, that Columbus principally addressed his reply. And he replied by discovering the New World. But had not this daring genius been supported in his projects by the Spanish sovereigns, Ferdinand and Isabella, he would have been handed over to the Inquisition, and condemned as a heretic. It was then so dangerous to believe in the Antipodes, that a Bishop of Salzburg was deposed from his episcopal throne, and deprived of his ecclesiastical dignity, by the Pope Zacharias, for having countenanced the heresy.

We now know why, for a whole series of centuries, men would not follow in the footsteps of Aristotle, who was the first to establish theoretically the sphericity of the earth.

The discovery of the New World, and the voyages of circumnavigation which rapidly succeeded one another, demonstrated, not only that inhabitants there are whose feet are opposite to ours, but that the earth does not rest upon any species of support; that it floats, like a star, freely in space.

The ice was broken. The question of the earth's figure was revived, and, this time, discussed in a new light.

Is the earth perfectly round?

Copernicus never doubted it; he who was the first, after Pythagoras, to represent our planet as revolving round the sun. The geometrical sphericity of the earth wonderfully harmonised with the perfect circles in which he supposed the planets to move. Kepler, who had first laid a sacrilegious hand on the holy figure of the circle, and on the circular orbits of the stars, never ventured, however, to dispute the perfect rotundity of the earth; it appeared to him a matter beyond all controversy. Galileo was the first to hazard a doubt. But this doubt became a certainty only through the labours of Huygens.

Galileo, who died in the very year that Newton was born (1642), had discovered, as we know, that all bodies, in falling, obey an uniformly accelerative force, called gravitation, and that the space traversed increases as the square of the time occupied in their descent. Huygens perceived that gravity varies according to the parallels of latitude, and it was not long before he demonstrated, by the number of oscillations which a pendulum of a certain length performs in a certain time, that it diminishes in a regular ratio as we approach the Equator, where it reaches its minimum, and that it augments, on the contrary, in due proportion as we approach the Poles, where it must attain its maximum. Strong in this knowledge, and knowing, moreover, that the material molecules, uniformly distributed in the volume of a sphere, act upon a point of its surface as if they were all reunited in the centre of that sphere, Huygens deduced from it the inequality of the equatorial and the polar radius; he attempted even to determine how much the former exceeded the latter. We know, now-a-days, that this difference is 139,670 feet (41,848,380—41,708,710 feet).

Newton admits, with Huygens, that the earth bulges out at the Equator and is flattened at the Poles; that, in a word, it is a spheroid of revolution. He went much farther: he made the precession of the Equinoxes depend upon this flattening; but he did not furnish its mathematical demonstration. What has been the result? A free skirmishing ground for all opinions.