Well, father, we have got rid of the root of our gum tree, as well as its bark and leaves—what shall we take next? I seem to know a good deal, but I cannot yet make out how the tree grows.
But you are prepared now to understand that part of my lesson to come. You see the rings of wood, and the rings of bark, and you want to know how they come there.
Yes, that I do. Of course I could say that the sap makes wood, as I know that bread and butter make flesh; but I want to understand how the change takes place.
Let us then imagine ourselves, Willie, to be spirits able to be inside of the tree, without taking up any room, and with our eyes about us to watch all that is done.
I wish I could do that; it would be better than flying.
Don’t talk about it, but jump inside along with me.
I am with you, father, with eyes and ears all open.
I’ll tell you what it is, Willie, we shall have not only to be inside the tree, but to be able to stay there a few weeks or months to notice all.
That is easy enough. We may as well fancy hundreds of years as millions of miles.
Let us go to the pith. Around here are vessels in the sheath of the pith. The circles of wood are ranged outside. We will pass along one of the Medullary or pith rays, which you saw make the silver lines of the wood, and here we are at the Liber or inner bark.