Page:Popular Science Monthly Volume 6.djvu/58

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48
THE POPULAR SCIENCE MONTHLY.

of the everlasting, are to stand for it; and the highest compliment man ever receives from Heaven is the sending to him its disguised and discredited angels." This is a grand exhortation, and has, no doubt, thrilled many a reader with enthusiasm for the rising thoughts of his time. But the difficulty still remains, how to identify the celestial messengers! Such are the eccentricities of human judgment, that the sympathy which Mr. Emerson invokes is as likely to be given to the worthless as to the worthy. And what shall we say about the duty of common mortals respecting the "disguised and discredited angels," when the Seer himself snubs the author of "First Principles" as a "stock-writer," and says to the author of that unclean imposture—"Leaves of Grass"—"I greet you at the beginning of a great career?"

 
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HUMAN LOCOMOTION.

THE movements executed by animals in transporting themselves from place to place have long engaged the attention of observers; and, as animals which travel on the land are more easily got at than those which frequent the sea and the air, it is the motions of such that we know most about. Yet much remains to be learned of the modes of progression of even the most familiar of these; and not a little probably will have to be unlearned that recent investigations have shown to be erroneous.

At first sight, the operations of walking and running, as displayed by both two-legged and four-legged creatures, may appear simple enough, but all attempts to analyze and explain them have shown that in reality they are very complex, so that there has arisen a wide diversity of opinion concerning their real nature. These disagreements among the investigators of the subject can only be accounted for on the principle of the insufficiency of the means at their command for complete investigation; and the confusion has been further increased by the difficulty of expressing in words the rhythm, duration, and phases of the rapid and complex movements involved.

Prof. E. J. Marey, of the College of France, a skillful physiologist, and the inventor of the various delicate mechanical appliances for tracing and registering obscure animal motions, has contributed to the "International Scientific Series" a work entitled "Animal Mechanism," in which the subject of terrestrial locomotion, as typified in man and in the horse, is fully treated. Prof. Marey has devised an apparatus which, applied to the extremities of a moving animal, enables each limb to write out a description, or make a picture of its own actions, so that the duration and phases of its movements, its periods of rest, and the relations of these to the corresponding features in the motions