« 上一頁繼續 »
as not to show any family resemblance. They resemble each other, in fact, only in the way that the shells of the British shores resemble those of the Indian Archipelago. Both series evidently served the same purpose, that of sheltering the animal; but they are provided with different contrivances, and are often built up in a different manner, because the circumstances of existence are and were exceedingly distinct.
What we have here said of shells applies equally well to all other animals, and even to all vegetable productions; and in proportion as they range widely now over the earth's surface, so do they seem to have extended far back in time, while the kinds that are limited in space are very local. The variety of forms in these lower animals is now very great, and has been in old time much greater; but still there are certain general principles and laws that seem to have governed them at all times, and these are so evidently related to the fitness of each created being for the time and place of its existence, that we learn to trust implicitly to such relations, and assume the conditions of life from the animal, or the structure of the living being from known conditions of existence, without fearing the possibility of error.
When, then, we find in almost all deposits, whether of limestone, sandstone, or clay, or any mixture of the three, the remains of species of animals once inhabiting the sea preserved without injury, and often very plentiful, and when we discover that each group of deposits is on the whole characterised by some special assemblage of animal or vegetable remains peculiar to itself, and no where exactly repeated, though we must suppose similar states of climate and temperature to have been often repeated, -geologists deduce one of those broad generalisations sometimes called laws of nature. The law thus discovered being in perfect harmony with all that is now known of the distribution of life, we may with greater reason accept it, and employ it in further inquiries.
From the study and application of this law, very large and important natural-history results have been obtained. Learning first, by careful observation, the various remains most abundant and most characteristic of the different deposits of one country, and working them into a regular series, these have been compared with corresponding series from another country adjacent. From this comparison, bearing in mind the difference of mineral character, the relative age of the two deposits has been determined, and in some cases independent evidence has confirmed the deci. sion thus made. With the peculiar fossils of a deposit are always mixed up a number that are common to other deposits above or below; but on the whole, as we have said, there is a nucleus that, with a little attention and study, may be recognised with much certainty. Stated in other words, this means that fossils are characteristic of formations.
It is a fact settled by observation, that fossils may safely be used to identify such deposits as were made in various places nearly at the same time. In this way, also, it has been found possible to prepare geological maps for whole continents that shall communicate a large amount of truth,
ases indeme age of the bearing in series from a regular
and not much chance of serious error, the relative position of all principal beds being made out by the comparison of the fossils found in them.
All kinds of fossils are useful for these purposes; but it will necessarily happen that the remains most easily recognised and least easily injured, those most abundant and most complete in themselves, and not the rarest or the most abnormal, will be the most generally useful. Thus sea-shells, star-fishes, sea-eggs, and sea-urchins, crabs, and other crustaceans, corals, and, when the microscope is at hand, those minute specks too small to be crushed, too delicate to be destroyed, called foraminifera, are all extremely useful; often far more so than strange and quaint fishes, reptiles, birds, and quadrupeds. All these are valuable when in sufficient abundance ; but number and variety are more important than peculiar structure.
The pre-Adamite world includes, then, a long series of creations of beings, each series adopted to the exigencies of its own day. If, as we suppose from the study of fossils, there were once warm swampy islands in these latitudes, instead of a large continent, we might have in our temperate zone a growth of tapirs, antelopes, and other animals fitted for the climate, together with monkeys, snakes, and vultures. If, on the contrary, the ice reached far down from the poles towards Southern Europe, and the climate was less genial, there was a corresponding supply of bears and the larger quadrupeds adapted to exposure by warm coats of fur, and finding abundant food in the twigs of trees. If, again, there was deep water over what is now dry land, we may understand the existence, as now in the mid-Atlantic, of abundant supplies of minuteforaminiferous shells covering the ocean floor; while, if the water were more shallow, perchance the remains of sharks and other strange marine creatures might be accumulated, together with a rich harvest of shells and of shoal-water animals. Or, lastly, if a river had emptied itself in the neighbourhood of deposits going on, there would be marks of fresh water, and the remains of land vegetation, insects, and land animals. In a word, all the peculiarities of deposit would be marked, and could be discovered by the nature of the organic remains.
No one who has not examined for himself can conceive the vast extent, the incredible wealth and profusion of nature, in this perpetual production of new forms and structures from time to time, as circumstances have changed throughout the world's history. Of all these a profusion of examples no doubt remains; but what are they in proportion to the number that is lost? We grope about in the dark, picking up here a little and there a little; but we can never hope to remove and bring to light all that is left, and there must remain to the last in the great burying-place of nature a far larger series than the most searching investigation of man will ever bring to light. Could we even attain to a complete knowledge of organic remains, we should have made but one step, and that an imperfect and incomplete step, towards an acquaintance with the life that has passed away; for there must still remain large gaps to be supplied of such animals as have passed out of existence, having had no durable skeleton and no hard part capable of conservation.
At the Lattice.
Behind the curtain,
With glance uncertain,
Still most surely
In leafy alleys
Where twilight dallies,
And where Summer tosses
Velvet verdant mosses,
Oh, thou beauty,
Hanging ripe and fruity
Whisper from the casement
“At the cottage basement,
But if vagrant lashes
Raise for whoso dashes
Close the lattice, sweetest !
And with bridle fleetest
ALFRED AUSTIN. August 1, 1861.
Stones proper for personal adornment may be classed as — first and supreme of all, of a species apart, peculiar, and isolated, holding no connection with any other “mineral flower," but standing alone in its kingly pride — the DIAMOND; then the princes of the throne, the hyaline or glass-like crystals — such as the ruby, sapphire, emerald, &c., — what fine people call “hyaline corindons;" then the translucent silicates, rockcrystal, and all the transparent quartz group; then feldspar, chalcedony, lapis lazuli, malachite, jasper; then jet and amber and coral; and, last of all, that peerless bit of phosphate of lime and gelatine, the moonlight-coloured pearl hid in the depths of the Indian Seas. This is not quite the classification of mineralogy, nor yet of taste or commercial value, but it answers the purposes of the present paper.
And first as to the diamond, that mineral king, crowned with such a diadem of glory as no other created thing possesses. The diamondAdamas, or the Indomitable, as it was called—is the hardest body known: it refuses to be tried save by its peers, and will not be cut or polished by any thing yet discovered but itself. A diamond must be cut by a diamond, and polished by diamond-dust; and when De Boot's apocryphal friend, the learned physician, said he could stick one on the point of a needle, and divide it into scales by the help of his nails alone, we are sorry to say that De Boot's apocryphal friend uttered simple fabrications. Unless, indeed, he had found out, in a secret Baconian kind of way, that diamond was only pure carbon,- the spiritual evolution of coal, the realisation of the carbonic ideal,- and so, when he spoke of the gem, meant only the chrysalis,-diamond in its antenatal tomb,—diamond with a smutty face and a flaming tongue, diamond burning in the grate, and helping to cook kid-steaks or fry the inevitable omelet, — diamond as coal or, scientifically, carbon. But as De Boot gives another anecdote of another apocryphal friend of his, who knew of his own knowledge that a lady had two hereditary diamonds, male and female, which engendered other diamonds in a quite satisfactory and matrimonial manner, we may dismiss his assertions with more respect for his learning than reliance on his accuracy. It was a very common belief, though, that all the nobler gems were sexual, as also that they possessed various mystic and even intelligent qualities which bound them up in close relation with man. Thus they all represented certain spiritual and moral vir'tues; they all gave certain powers to their wearers; they all showed the presence of poison-some of them turning dark and turbid, others pale and sickly, and some shattering themselves to pieces in passionate despair and abhorrence at its touch. But, beyond these useful generic properties, the diamond had its own peculiar virtues such as none other possessed. Thus, when worn in the ephod of the Jewish high-priest, it
Forms the buttonant blue diamond, richness of the timen
gave token of the guilt or innocence of the accused. If guilty, the gem became dim and lustreless; if guilty unto death, it flamed with a sullen flare of fierce blood-red; but if innocent, it shone with tenfold glory. The diamond symbolised innocence, justice, faith, strength, and the impassivity of fate, and, under its name of Adamant, expressed all that human life knows of unchangeable will and the power of resistance. “It gives way to no sort of matter, neither fire nor iron," says Camillus Leonardus, physician to Cæsar Borgia, “but despises all;" and an old blackletter book says that “God hath induyd hym with greatter vertues than many other stones,” albeit all are indued with many.
If a diamond has a greenish tinge on the thick veil or covering which it has worn in the mine, it will prove a fair and noble gem; if tinged with yellow, it will be greasy, soft, and comparatively valueless. Diamonds are often found coloured, and when so are valuable in proportion to the fullness and richness of the tint; as witness Mr. Hope's magnificent blue diamond, and that glorious green gem which forms the button in the King of Saxony's state - hat. Even perfectly black diamonds have been found, but these are rare; and Mr. Meyer's, in the Great Exhibition, was held to be a great curiosity. It weighed 350 carats (a carat is equal to 34 rains troy, six carats being equal to nineteen grains troy), and was so hard that nothing could cut or polish it, not even the dust of its white brethren. The small, soft, and ill-complexioned diamonds, neither purely colourless nor richly tinged, are broken up for diamond-dust worth fifty pounds the ounce, and used for cutting cameos and onyxes, as well as for polishing their uncivilised relations. Indeed, carnelians, agates, cairngorms, &c. could not be engraved by any other agent than diamond-dust; though the ancients engraved even the “hyaline corindons” by means of their metal tools alone, and made no use of diamond-dust. But we have lost a few arts, as well as gained many, since the days of our brave old bearded elders.
The difference between brilliant, rose, and table diamonds consists only in the cutting. Three hundred and fifty years ago all diamonds were cut with four flat surfaces,—these were Indian-cut or table diamonds; later they were cut in the form of half a polyhedron resting on a plane section,—this was the rose diamond; and a short time after this innovation Mazarine caused twelve to be cut as brilliants, yet known among the crown - jewels of France as the Twelve Mazarines. That is, they were cut into the form of two truncated pyramids, the upper, or bizel, being much more deeply truncated than the lower, or collet, and having thirty-two facets inclined under different angles, while the lower has but twenty-four; each facet, both of the bizel and collet side, having its own distinctive name and arbitrary proportion. This is the most effective, but the most wasteful, way of cutting diamonds- about one-half the weight being lost in converting them into brilliants or roses from the rough. Old diamonds are more carefully cut than the quite modern, and are worth forty or fifty per cent more. The most celebrated dia