Notes of a Reader
THE ATMOSPHERE.—CLIMATOLOGY.
(From Part XIV. of Knowledge for the People; or, the Plain Why and Because.)
Why may the atmosphere be termed a fourth kingdom of Nature?
Because it extends its influence in an equal degree over the three kingdoms, the animal, the vegetable, and the mineral, operates upon each after a distinct manner, and appears rather to be independent, and allied to all of them, than to be rightly included within any one.
Why is a knowledge of the atmosphere important to the naturalist?
Because it serves to throw much light on the history and functions both of the animal and vegetable creation; for it is through this great medium that heat, light, electricity, oxygen, and the great springs of vital phenomena, are conveyed to all classes of organized matter. It is by means of this wonderful agent, that we gain the theory of respiration in all classes of creatures possessing animal life; and that we become acquainted with the migrations of animals, as well as many of their peculiar instincts and habits. It is the atmosphere that enables us to account for the periodical changes in the plumage of birds and the furs of animals, and the variety of colours to be found amongst them. By means also of the elasticity of the atmosphere, sounds and odours are transmitted to sensitive beings. Atmospherical phenomena, it may be safely inferred, attracted the observation of mankind in the earliest ages: we know that the Egyptians and the Greeks wrote upon the subject; the Jews too, a pastoral people, "could discern the face of the sky;" and even in our day, shepherds may be ranked among the weather-wise. "This is a fine morning, a soft day, or a cold evening," are modes of salutation with us, as commonly as is the "Salem Alikem" (Peace be with you!) amongst the inhabitants of the more serene countries of the East. Shenstone says, though with nearly equal spleen and truth: "there is nothing more universally commended than a fine day: the reason is, that people can commend it without envy."
Why do we call the atmosphere a fluid?
Because it has a tendency to move in all directions, and consequently rushes in and fills every space not previously occupied by a more solid substance. Hence we find, that every cave, crevice, place, and vessel, having communication with the atmosphere, if it be not filled with something else, is filled with air; against which it is no argument that we do not see it, as it is perfectly transparent, and consequently invisible.