Leave those pretty little scissors of yours, with which you would try in vain to make a fire, outside your window for two or three days, and then observe the dreadful, scaly, red stain which you are sure to find on them afterwards, and which is called rust. Have you any idea whence it proceeds? I will tell you. It comes from the oxygen, which has been making one of those cheerless secret marriages with the iron of your scissors. So there have been no pretty sights nor sounds, no lights nor cheerful noises to entertain anybody, and though people may have wished for them ever so much, they have had to do without them.
I will tell you the true reason of these marriages incognito. It is because oxygen is but feebly attracted by iron, who does not stand so high in his good graces as many other bodies, and so (to continue the joke) he unites slowly and languidly with him, as we may say.
Now tell me, when you set fire to a bit of paper, how long does it take to burn?
Half a minute, at the utmost, you answer.
Very good. And how long does it take to produce that rust-stain, even though it is probably not a hundredth part the size of the paper?
Two or three days, is your reply, for so I told you my self.
Here is a strange difference indeed; but from it you may discover why you have not seen any signs of rejoicing or illuminations at the iron wedding. These are always in proportion to the quantity of oxygen which is being married at once—and this was—oh, such a slow affair! When the quantity is very small indeed, the festal illuminations are very small indeed too, and in fact escape observation altogether. In the same way that you would not be conscious of little bits of thread laid delicately one after another on your back, whereas you would plainly feel a large sheet, were it to fall on your shoulders. Yet what is the large sheet but a great quantity of little bits of thread? Only in that case they would all come upon you at once, like the marriage illuminations of burning paper.
Wait a little longer and we shall finish.
What is there, then, in the paper which pleases the oxygen so much that he unites himself to it so readily, and in such large quantities?
What is there? Two substances of high degree, who have actually risen to the dignity of a royal alliance, by the important part they play in the world; one of these, charcoal or carbon, we know quite well already; the other I have only mentioned to you in connection with water, HYDROGEN. Thanks to gas companies, everybody in these days knows hydrogen, at least by name. But before proceeding, I will just tell you that it is by far the lightest body that is known. It is forty and a half times lighter than air, which is not very heavy itself, although in the mass it has its weight, as we have seen.