So now remember that chalk is carbonate of lime, and that it is made up of three things, calcium, oxygen, and carbon; and that therefore its mark is CaCO₃, in Analysis's language, which I hope you will be able to read some day.

But how is it that Analysis and Synthesis cannot take all this chalk to pieces, and put it together again?

Look here; what is that in the chalk?

Oh! a shepherd's crown, such as we often find in the gravel, only fresh and white.

Well; you know what that was once. I have often told you:—a live sea-egg, covered with prickles, which crawls at the bottom of the sea.

Well, I am sure that Master Synthesis could not put that together again: and equally sure that Master Analysis might spend ages in taking it to pieces, before he found out how it was made. And—we are lucky to-day, for this lower chalk to the south has very few fossils in it—here is something else which is not mere carbonate of lime. Look at it.

A little cockle, something like a wrinkled hazel-nut.

No; that is no cockle. Madam How invented that ages and ages before she thought of cockles; and the animal which lived inside that shell was as different from a cockle-animal as a sparrow is from a dog. That is a Terebratula, a gentleman of a very ancient and worn-out family. He and his kin swarmed in the old seas, even as far back as the time when the rocks of the Welsh mountains were soft mud; as you will know when you read that great book of Sir Roderick Murchison's, "Siluria." But as the ages rolled on, they got fewer and fewer, these Terebratulæ; and now there are hardly any of them left; only six or seven sorts are left about these islands, which cling to stones in deep water; and the first time I dredged two of them out of Loch Fyne, I looked at them with awe, as on relics from another world, which had lasted on through unnumbered ages and changes, such as one's fancy could not grasp.

But you will agree that, if Master Analysis took that shell to pieces, Master Synthesis would not be likely to put it together again; much less to put it together in the right way, in which Madam How made it.

And what was that?

By making a living animal, which went on growing, that is, making itself; and making, as it grew, its shell to live in. Synthesis has not found out yet the first step towards doing that; and, as I believe, he never will.

But there would be no harm in his trying?

Of course not. Let everybody try to do everything they fancy. Even if they fail, they will have learnt at least that they cannot do it.

But now—and this is a secret which you would never find out for yourself, at least without the help of a microscope—the greater part of this lump of chalk is made up of things which neither Analysis can perfectly take to pieces, nor Synthesis put together again. It is made of dead organisms, that is, things which have been made by living creatures. If you washed and brushed that chalk into powder, you would find it full of little things like the Dentalina in this drawing, and many other curious forms. I will show you some under the microscope one day.

They are the shells of animals called Foraminifera, because the shells of some of them are full of holes, through which they put out tiny arms. So small they are and so many, that there may be, it is said, forty thousand of them in a bit of chalk an inch every way. In numbers past counting, some whole, some broken, some ground to the finest powder, they make up vast masses of England, which are now chalk downs; and in some foreign countries they make up whole mountains. Part of the building stone of the Great Pyramid in Egypt is composed, I am told, entirely of them.

And how did they get into the chalk?

Ah! how indeed? Let us think. The chalk must have been laid down at the bottom of a sea, because there are sea-shells in it. Besides, we find little atomies exactly like these alive now in many seas; and therefore it is fair to suppose these lived in the sea also.

Besides, they were not washed into the chalk by any sudden flood. The water in which they settled must have been quite still, or these little delicate creatures would have been ground into powder—or rather into paste. Therefore learned men soon made up their minds that these things were laid down at the bottom of a deep sea, so deep that neither wind, nor tide, nor currents could stir the everlasting calm.

Ah! it is worth thinking over, for it shows how shrewd a giant Analysis is, and how fast he works in these days, now that he has got free and well fed;—worth thinking over, I say, how our notions about these little atomies have changed during the last forty years.

We used to find them sometimes washed up among the sea-sand on the wild Atlantic coast; and we were taught, in the days when old Dr. Turton was writing his books on British shells at Bideford, to call them Nautili, because their shells were like Nautilus shells. Men did not know then that the animal which lives in them is no more like a Nautilus animal than it is like a cow.

For a Nautilus, you must know, is made like a cuttle-fish, with eyes, and strong jaws for biting, and arms round them; and has a heart, and gills, and a stomach; and is altogether a very well-made beast, and, I suspect, a terrible tyrant to little fish and sea-slugs, just as the cuttle-fish is. But the creatures which live in these little shells are about the least finished of Madam How's works. They have neither mouth nor stomach, eyes nor limbs. They are mere live bags full of jelly, which can take almost any shape they like, and thrust out arms—or what serve for arms—through the holes in their shells, and then contract them into themselves again, as this Globigerina does. What they feed on, how they grow, how they make their exquisitely-formed shells, whether, indeed, they are, strictly speaking, animals or vegetables, Analysis has not yet found out. But when you come to read about them, you will find that they, in their own way, are just as wonderful and mysterious as a butterfly or a rose; and just as necessary, likewise, to Madam How's work; for out of them, as I told you, she makes whole sheets of down, whole ranges of hills.

No one knew anything, I believe, about them, save that two or three kinds of them were found in chalk, till a famous Frenchman, called D'Orbigny, just thirty years ago, told the world how he had found many beautiful fresh kinds; and, more strange still, that some of these kinds were still alive at the bottom of the Adriatic, and of the harbour of Alexandria, in Egypt.

Then in 1841 a gentleman named Edward Forbes,—now with God—whose name will be for ever dear to all who love science, and honour genius and virtue,—found in the Ægean Sea "a bed of chalk," he said, "full of Foraminifera, and shells of Pteropods," forming at the bottom of the sea.

And what are Pteropods?

What you might call sea-moths (though they are not really moths), which swim about on the surface of the water, while the right-whales suck them in tens of thousands into the great whalebone net which fringes their jaws. Here are drawings of them. 1. Limacina (on which the whales feed); and 2. Hyalea, a lovely little thing in a glass shell, which lives in the Mediterranean.

But since then strange discoveries have been made, especially by the naval officers who surveyed the bottom of the great Atlantic Ocean before laying down the electric cable between Ireland and America. And this is what they found:

That at the bottom of the Atlantic were vast plains of soft mud, in some places 2,500 fathoms (15,000 feet) deep; that is, as deep as the Alps are high. And more: they found out, to their surprise, that the oozy mud of the Atlantic floor was made up almost entirely of just the same atomies as make up our chalk, especially Globigerinas; that, in fact, a vast bed of chalk was now forming at the bottom of the Atlantic, with living shells and sea-animals of the most brilliant colours crawling about on it in black darkness, and beds of sponges growing out of it, just as the sponges grew at the bottom of the old chalk ocean, and were all, generation after generation, turned into flints.

And, for reasons which you will hardly understand, men are beginning now to believe that the chalk has never ceased to be made, somewhere or other, for many thousand years, ever since the Winchester Downs were at the bottom of the sea; and that "the Globigerina-mud is not merely a  chalk formation, but a continuation of the  chalk formation, so that we may be said to be still living in the age of Chalk." Ah, my little man, what would I not give to see you, before I die, add one such thought as that to the sum of human knowledge!

So there the little creatures have been lying, making chalk out of the lime in the sea-water, layer over layer, the young over the old, the dead over the living, year after year, age after age—for how long?

Who can tell? How deep the layer of new chalk at the bottom of the Atlantic is, we can never know. But the layer of live atomies on it is not an inch thick, probably not a tenth of an inch. And if it grew a tenth of an inch a year, or even a whole inch, how many years must it have taken to make the chalk of our Downs, which is in some parts 1,300 feet thick? How many inches are there in 1,300 feet? Do that sum, and judge for yourself.

One difference will be found between the chalk now forming at the bottom of the ocean, if it ever become dry land, and the chalk on which you tread on the Downs. The new chalk will be full of the teeth and bones of whales; warm-blooded creatures, who suckle their young like cows, instead of laying eggs, like birds and fish. For there were no whales in the old chalk ocean; but our modern oceans are full of cachalots, porpoises, dolphins, swimming in shoals round any ship; and their bones and teeth, and still more their ear-bones, will drop to the bottom as they die, and be found, ages hence, in the mud which the live atomies make, along with wrecks of mighty ships,

and all that man has lost in the deep seas. And sadder fossils yet, my child, will be scattered on those white plains:—