Now he can take a bit of chalk to pieces, so that it shall become several different things, none of which is chalk, or like chalk at all. And then his brother Synthesis can put them together again, so that they shall become chalk, as they were before. He can do that very nearly, but not quite. There is, in every average piece of chalk, something which he cannot make into chalk again when he has once unmade it.
What that is I will show you presently; and a wonderful tale hangs thereby. But first we will let Analysis tell us what chalk is made of, as far as he knows.
He will say--Chalk is carbonate of lime.
But what is carbonate of lime made of?
Lime and carbonic acid.
And what is lime?
The oxide of a certain metal, called calcium.
What do you mean?
That quicklime is a certain metal mixed with oxygen gas; and slacked lime is the same, mixed with water.
So lime is a metal. What is a metal? Nobody knows.
And what is oxygen gas? Nobody knows.
Well, Analysis, stops short very soon. He does not seem to know much about the matter.
Nay, nay, you are wrong there. It is just "about the matter" that he does know, and knows a great deal, and very accurately; what he does not know is the matter itself. He will tell you wonderful things about oxygen gas--how the air is full of it, the water full of it, every living thing full of it; how it changes hard bright steel into soft, foul rust; how a candle cannot burn without it, or you live without it. But what it is he knows not.
Will he ever know?
That is Lady Why's concern, and not ours. Meanwhile he has a right to find out if he can. But what do you want to ask him next?
What? Oh! What carbonic acid is. He can tell you that. Carbon and oxygen gas.
But what is carbon?
Nobody knows.
Why, here is this stupid Analysis at fault again.
Nay, nay, again. Be patient with him. If he cannot tell you what carbon is, he can tell you what is carbon, which is well worth knowing. He will tell you, for instance, that every time you breathe or speak, what comes out of your mouth is carbonic acid; and that, if your breath comes on a bit of slacked lime, it will begin to turn it back into the chalk from which it was made; and that, if your breath comes on the leaves of a growing plant, that leaf will take the carbon out of it, and turn it into wood. And surely that is worth knowing,--that you may be helping to make chalk, or to make wood, every time you breathe.
Well; that is very curious.
But now, ask him, What is carbon? And he will tell you, that many things are carbon. A diamond is carbon; and so is blacklead; and so is charcoal and coke, and coal in part, and wood in part.
What? Does Analysis say that a diamond and charcoal are the same thing?
Yes.
Then his way of taking things to pieces must be a very clumsy one, if he can find out no difference between diamond and charcoal.
Well, perhaps it is: but you must remember that, though he is very old--as old as the first man who ever lived--he has only been at school for the last three hundred years or so. And remember, too, that he is not like you, who have some one else to teach you.
He has had to teach himself, and find out for himself, and make his own tools, and work in the dark besides. And I think it is very much to his credit that he ever found out that diamond and charcoal were the same things. You would never have found it out for yourself, you will agree.
No: but how did he do it?
He taught a very famous chemist, Lavoisier, about ninety years ago, how to burn a diamond in oxygen--and a very difficult trick that is; and Lavoisier found that the diamond when burnt turned almost entirely into carbonic acid and water, as blacklead and charcoal do; and more, that each of them turned into the same quantity of carbonic acid, And so he knew, as surely as man can know anything, that all these things, however different to our eyes and fingers, are really made of the same thing,--pure carbon.
But what makes them look and feel so different?
That Analysis does not know yet. Perhaps he will find out some day; for he is very patient, and very diligent, as you ought to be. Meanwhile, be content with him: remember that though he cannot see through a milestone yet, he can see farther into one than his neighbours. Indeed his neighbours cannot see into a milestone at all, but only see the outside of it, and know things only by rote, like parrots, without understanding what they mean and how they are made.
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 CaCO(3), 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.