these rivers annually pour into the Atlantic and the Arctic Oceans. In finding the place" of all this water, it is incumbent upon them to show us the winds which bring it also, and to point out its channels.
287. Spirit in which the search for truth should be conducted.—"In the greater number of physical investigations some hypothesis is requisite, in the first instance, to aid the imperfection of our senses; and when the phenomena of nature accord with the assumption, we are justified in believing it to be a general law." [1]
288. The number of known facts that are reconciled by the theory of a crossing at the calm belts.—In this spirit this hypothesis has been made. Without any evidence bearing upon the subject, it would be as philosophical to maintain that there is no crossing at the calm belts as it would be to hold that there is; but nature suggests in several instances that there must be a crossing. (1.) In the homogeneousness of the atmosphere (§ 237). The vegetable kingdom takes from it the impurities with which respiration and combustion are continually loading it; and in the winter, when the vegetable energies of the northern hemisphere are asleep, they are in full play in the southern hemisphere. And is it consistent with the spirit of true philosophy to deny the existence, because we may not comprehend the nature, of a contrivance in the machinery of the universe which guides the impure air that proceeds from our chimneys and the nostrils of all air-breathing creatures in our winter over into the other hemisphere for re-elaboration, and which conducts across the calm places and over into this that which has been replenished from the plains and sylvas of the south? (2.) Most rain, notwithstanding there is most water in the southern hemisphere, falls in this. How can vapour thence come to us except the winds bring it, and how can the winds fetch it except by crossing the calm places? (3.) The "sea-dust" of the southern hemisphere, as Ehrenberg calls the red fogs of the Atlantic, has its locus on the other side of the equator, but it is found on the wings of the winds in the North Atlantic Ocean. If this be so, it must cross one or more of the calm belts.[2]
- ↑ Mrs. Somerville.
- ↑ After this had been written, I received from my colleague, Lieut. Andrau, an account of the following little tell-tale upon this subject:— "I found a confirmation of your theory in a piece of vegetable substance caught in a small sack (hoisted up above the tops) between 22°-25° lat. N., and 38°-39°long. W. This piece is of the following dimensions:—14 millim. long.
