Page:Popular Science Monthly Volume 46.djvu/585

Rh wands, tubes, banners, stones, amulets, pendants, butterfly gorgets, ear bobs, bracelets, breastplates, beads, buttons, headdresses, labrets, nose rings, charms, and a score of others, they are delineated in many volumes. To ascribe a purpose to any pattern, unless a similar one has been seen in actual service, would be as presumptuous as the attempt by a person entirely ignorant of modern secret societies to explain the meaning of badges, pins, or regalia. No doubt some of them owe their form to a whim or fancy of the maker; others were purely decorative; while many of them were symbolic, or for use in the manifold dances, parades, celebrations, superstitious ceremonies, and other observances so dear to the minds of an uncultured people. The manner of perforation in some indicates that they were for suspension by cord; in others, that they were to be placed upon a staff; still others, unperforated, may have been secured in various ways. Nearly all are made of material that would break if carelessly handled; many are of such size or shape that no particular use for them can be imagined. There is less trouble in regard to the utensils, weapons, or implements for ordinary work, comprising articles necessary in agriculture, hunting, warfare, or domestic affairs. What sort of work the prehistoric people may have done in wood, textile fabrics, feathers, fur, robes, skins, or other perishable material, can never be known; but judging from the few scraps remaining, and from such other specimens as have been preserved, it was probably on a par with that of the present day among tribes but little changed from their condition when first known to the whites. Mi-. Fowke's notes are published, with plates, by Robert Clarke & Co., Cincinnati.

Roger Bacon's Dream of Steam and of Air-Ships.—An essay by Roger Bacon, published in 1618, has been brought to attention by M. de Fonvielle, which contains dim predictions of steam power and the navigation of the air. "Instruments," the author says in this essay, "may be made for navigating without any men pulling the oars, with a single man governing, and going quicker than if they were full of pulling men. . . . Wagons can also be made, that without any horse they should be moved with such a velocity that it should be impossible to measure it. . . . It is possible also to devise instruments for flying, such that a man being in the center if revolving something by which artificial wings are made to beat the air in the fashion of birds. . . . It is also possible to devise instruments which will permit persons to walk on the bottom of the sea. . . . All these things have been done in old times and in our times, except the instrument for flying, which I have not seen, and I have not known any man who saw it done."

The Test of Exactness.—Admitting that the prevailing opinion that great advances have recently been made in astronomy is correct so far as the fields of spectrum analysis and the measurement of minute quantities of radiant heat are concerned. Dr. William Harkness showed in his vice-presidential address at the American Association that the solution of the vast majority of astronomical problems depends upon the exact measurement of angles, and in that little or no progress has been made. Bradley, with his zenith sector a hundred and fifty years ago, and Bessel and Struve, with their circles and transit instruments seventy years ago, made observations not sensibly inferior to those of the present day, and indeed it would have been surprising if they had not done so. The essentials for accurately determining star places are a skilled observer, a clock, and a transit circle, the latter consisting of a telescope, a divided circle, and four micrometer microscopes. Surely no one will claim that we have to-day any more skillful observers than were Bessel, Bradley, and Struve, and the only way in which we have improved upon the telescopes made by Dollond one hundred and thirty years ago is by increasing their aperture and relatively diminishing their focal distance. The most famous dividing engine now in existence was made by the elder Repsold seventy-five years ago; but, as the errors of divided circles and their micrometer microscopes are always carefully determined, the accuracy of the measured angles is quite independent of any small improvement in the accuracy of the divisions or of the micrometer screws. Only in the matter of clocks has there been some advance, and even that is not very great. On the whole,