THE POPULAR SCIENCE MONTHLY.
tects a part, small though it be, of the soil from the direct warmth of the sun. Forests thus are like great canopies sheltering from the sun's rays those sections upon which they grow. Lands so covered possess a capacity for holding much moisture. Contained in the leaves and trunks of trees, and more particularly in the spongy moss and numerous streams, it is saved from rapid evaporation, and consequently lowers the temperature of the atmosphere over it.
Vapors, then, attracted toward mountains by gravity, or carried thither by winds, will at times collect first over those sections which are wooded, and will have a tendency to remain there, be condensed, and deposit rain.
It may not be out of place to notice here another fact coming under my observation. Winds sweeping across a country, when they encounter mountains, are crowded against them, and, by the pressure from behind, are forced up along their sides and over their crests. Clouds that are in their paths, and which are borne onward to the slopes of such mountains, are sometimes carried up to and over their tops. Slopes which are destitute of timber present very few obstacles to such a result. Forests, on the other hand, break or lessen the mechanical strength of wind, and so increase the probability of their augmenting the volume of rainfall.
|P. F. Schofield.|
|New York, September, 1875.|
WHICH UNIVERSE SHALL WE STUDY?
A CERTAIN class of astronomers have aimed to persuade us that there are "more worlds than one;" and those ingenious speculators Stewart and Tait have recently argued for two universes: the present universe, open to the sense, and an "unseen universe" beyond the range of direct scientific investigation but open to intrepid scientific faith. From another point of view this idea of two universes comes out in a much more definite and practical way; and that is when considered with reference to the two great orders of knowledge that are now making rival claims on the attention of mankind as means of education. This conception of two universes as objects of thought was very instructively set forth by the able author of the articles we have published under the title of "The Deeper Harmonies of Science and Religion," in his third paper, and the passage defining the distinction is so well drawn that it will bear repetition. The writer says:
"There is something which sets itself up as a just reflection of the universe, and which it is possible to study as if it were the universe itself; that is, the multitude of traditional unscientific opinions about the universe. These opinions are, in one sense, part of the universe; to study them from the historic point of view is to study the universe; but when they are assumed as an accurate reflection of it so as to divert attention from the original, as they are by all the votaries of authority or tradition, then they may be regarded as a spurious universe outside and apart from the real one, and such students of opinion may be said to study, and yet not to study the universe.
"This spurious universe is almost as great as the genuine one. There are many profoundly learned men whose whole learning relates to it and has no concern whatever with reality. The simplest peasant, who, from living much in the open air, has found for himself, unconsciously, some rules to guide him in divining the weather, knows something about the real universe; but an indefatigable student, who has stored a prodigious memory with what the schoolmen have thought, what the philosophers have thought, what the fathers have thought, may yet have no