Page:Popular Science Monthly Volume 12.djvu/768

748 we are now able to do indirectly, though only by long and difficult processes of investigation?

This is certainly a dictate of common-sense. The test of clairvoyance is what the alleged exceptional clearness shows. The question is, Can the clairvoyant actually do what he pretends to do? And the proof is not the mere testimony of a few parties, who say they have seen extraordinary things, but what has been positively, and demonstrably, and openly gained to science? This is the test in the case of all other scientific discoveries. M. Burdin, a member of the Academy of Sciences, put the claims of clairvoyance to very simple and decisive proof in 1837, when the real "evidence" signally failed. He placed 3,000 francs in the hands of a notary, subject to the order of the Academy, to be given to any one who would read writing placed in an opaque box, a committee of the Academy being appointed to supervise the experiments. The conditions were modified in various ways to suit objectors, the only point being to determine whether the clairvoyant could actually see through an opaque substance, and the time allowed to find a party who could do this, at first two years, was extended to three. Numerous trials were made, but none succeeded. The result, however, of the carefully-conducted experiments was to detect, in several instances, the fraudulent mode in which the alleged previous successes had been obtained.

the eminent director of the observatory at Meudon (France), has for some time been giving his attention to solar photography, and with singular success. The very remarkable photographs he has lately produced have hardly yet reached this country; but, from the examination of one, sent by him to the Allegheny Observatory, and which we have had the opportunity of seeing, we find that the praise bestowed abroad upon these new results is fully deserved.

The surface of the sun itself has been described by recent observers as consisting of a relatively dark background, thickly starred in every part by those strange objects called technically "granules," or "rice-grains," and which constitute the real source of the solar light. These, which have hitherto only occasionally been seen by good telescopes, are now definitely fixed for us by the camera, and we may see for ourselves that they, with their surrounding gray, do resemble—to compare great things with small—rice in a plate of soup, though the photograph shows that they are not in general elongated, but nearly round, with an irregular outline, as described by careful observers. We must leave, however, to special students the study of these details, and only observe that the photograph, besides confirming previous optical observations as to the remarkable fact that the light and heat of the sun come from but a small part of its surface, adds otherwise directly to our knowledge, by presenting new facts, such as the evidence of storms upon the solar surface (quite away from the spots), which have never yet been distinctly observed by the telescope.

These admirable photographs can hardly fail to soon become known, by copies to the scientific public, for they constitute a most essential step in the study of the sun, and one on which M. Janssen is certainly to be congratulated.

a certain sense, this "acoustical marvel of the century" is as simple as a grindstone; but, in a scientific point of view, there are subtile questions about it that only trained physicists can appreciate. Prof. Mayer's article upon the subject, in the foregoing pages, besides accurately explaining the