And he will gain much by this study, for all nature teaches us that this is the mode in which the Great Power works. Not “in the whirlwind,” or by sudden and violent new creations, but by the “still small voice” of gentle and gradual change, ordering so the laws of being that each part shall model and remodel itself as occasion requires. Could we but see the whole, we should surely bend in reverence and awe before a scheme so grand, so immutable, so irresistible in its action, and yet so still, so silent, and so imperceptible, because everywhere and always at work. Even now to those who study nature, broken and partial as their knowledge must be, it is incomprehensible how men can seek and long for marvels of spasmodic power, when there lies before them the greatest proof of a mighty wisdom in an all-embracing and never-wavering scheme, the scope of which is indeed beyond our intelligence, but the partial working of which is daily shown before our very eyes. But to return to our shifting scene where the dense forests of the Coal Period next come before us. There, while numerous fish, small and great, fill the waters, huge Newts have begun their reign (_Labyrinthodonts_), wandering in the marshy swamps or swimming in the pools, while smaller forms run about among the trees, or, snake-like in form, wriggle among the ferns and mosses; and one and all of these lead the double-breathing or amphibian life. In the next scene the coal forests are passing away, though still the strange forms of the trees and the gigantic ferns tell us we have not left them quite behind; and now upon the land are true air-breathers,[192] no longer beginning life in the water, but born alive, as the young ones of the black salamander are now (see p. 81). The Reptiles have begun their reign, and they show that, though still cold-blooded animals, they have entered upon a successful line of life, for they increase in size and number till the world is filled with them. Meanwhile other remarkable forms now appear leading off to two new branches of backboned life. On the one hand, little insect-eating warm-blooded marsupials scamper through the woods, having started we scarcely yet know when or where, except that we learn from their structure that they probably branched off from the amphibians in quite a different line from the reptiles, and certainly gained a footing upon the earth in very early times. On the other hand, birds come upon the scene having teeth in their mouths,[193] long-jointed tails,[194] and many other reptilian characters. We have indeed far more clue to the relationship of the birds than we have of the marsupials, for while we have these reptile-like birds, we have also the bird-like reptiles such as the little Compsognathus, which hopped on two feet, had a long neck, bird-like head and many other bird-like characters, though no wings or feathers.