POPULAR SCIENCE MONTHLY.
radio-activity, or the property it has of emitting the peculiar light-rays-which have recently attracted attention. The property has been attributed to the presence of uranium, one of the most radio-active among the known metals. About a year ago the chemists M. and Madame Curie, examining the different substances in pitchblende, found among them two new radiant substances, both more active than uranium, which they called polonium and radium. Polonium was found to be closely akin to bismuth, accompanying that metal in all its reactions, but separable from it by fractionation. Radium resembles barium in its chemical reactions. Recently M. A. Debierne, examining one of the products of solution and precipitation of pitchblende, observed intensified radio-active properties in a portion containing titanium, and on further investigation found still another substance showing the principal analytical properties of titanium, but which emitted extremely active rays. While these rays were comparable with those observed from polonium and radium, the chemical properties are entirely different from those of these substances. Radium, however, is spontaneously luminous, while the new substance is not.
Some recent experiments were made by Armand Gautier on the amount of the chlorides contained in sea air. They were conducted at the lighthouse at Rochedouvres, situated about fifty-five kilometres from the coast, during and after the long continuance of a good breeze directly inshore from the Atlantic. The air was drawn through a long tube containing glasswork, and this well then analyzed. He found that in a litre of air there was only 0.022 of a gramme of chloride of sodium. Small as this quantity is, it suffices, perhaps, with the aid of the traces of sodium present, to give sea air its tonic qualities.
The second International Congress on Hypnotism is to be held in Paris, August 12 to 16, 1900, Dr. Jules Voisin presiding. The programme of discussions includes such topics as the terminology of hypnotism, its relations to hysteria, its application to general therapeutics, the indications of it and suggestions for the treatment of mental disease and alcoholism, its application to general pedagogy and mental orthopædics, its value as a means of pathological investigation, its relation to the practice of medicine and to jurisprudence, and special responsibilities arising from the practice of experimental hypnotism.
The following is from a recent letter to Science by Prof. James H. Hyslop, of Columbia University: "So much has been published far and wide this last summer about my intention 'to scientifically demonstrate the immortality of the soul within a year,' that it is due to the facts bearing upon the choice between materialism and spiritism to say that I have never made any such professions as have been alleged. I wish the scientific public that still has the bad habit of reading and believing the newspapers to know that I was careful to deny that I made any such pretensions as were so generally attributed to me. More than one half the interviews alleged to have been held with me were the fabrications of reporters who never saw me, and the other half omitted what I did say and published what I did not say."
Some novel results have been obtained by M. Baillaud, of the Toulouse Observatory, France, from recent observations of the annular nebula in Lyra and comparisons with photographs taken in 1890. Among them are the discovery of small stars in the central space of the ring, the existence of bright points on the ring itself, a more distinct figure of the central star on the later photographs, giving it the aspect of a true star, and greater brightness in the central space, and certain changes in the shape of the edge of the ring, which shows at one point, more distinctly than in 1890, an eminence indicating a jet of matter escaping from the ring. Other nebulae, especially that called the Dumb-bell and the nebula in the Crown, are spoken of as exhibiting similar phenomena.
The Chicago Manual-Training School, which is said to be the first independent