If you look at a tree, you will easily notice that it's growth as well as it's fruitfulness tends sometimes to one part, sometimes to the other; in this year it will sprout luxuriantly on the northern side, but on the southern side everything will be weaker; in another year you will discover a striking polar change in the same tree; it's south side will be the most luxuriant, whereas the north side will look stunted. Also, soon on one side of the tree, soon on the other, more or less dead branches or twigs will appear; thus, soon on one side of the tree, soon on the other, the foliage will wither sooner or later at autumn time. – The Earth, Chapter 3, Paragraph 4