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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, e.varaining 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 bis- 

 muth, accompanying that metal in all 

 its reactions, but separable from it by 

 fractionation. Radium resembles ba- 



rium in its chemical reactions. Recent- 

 ly M. A. Debierne, examining one of 

 the products of solution and precipita- 

 tion of pitchblende, observed intensified 

 radio-active properties in a portion con- 

 taining titanium, and on further inves- 

 tigation found still another substance 

 showing the principal analytical prop- 

 erties of titanium, but which emitted 

 extremely active rays. While these 

 rays were comparable with those ob- 

 served from polonium and radium, the 

 chemical properties are entirely diflfer- 

 ent from those of these substances. Ra- 

 dium, however, is spontaneously lumi- 

 nous, while the new substance is not. 



MINOR PARAGRAPHS. 



SoiiE 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 Atlan- 

 tic. The air was drawn through a long 

 tube containing glasswork, and this well 

 then analyzed. He found that iii 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 discus- 

 sions includes such topics as the termi- 

 nology of hypnotism, its relations to 

 hysteria, its application to general ther- 

 apeutics, the indications of it and sug- 

 gestions for the treatment of mental dis- 

 ease and alcoholism, its application to 

 general pedagogy and mental orthopae- 

 dics, its value as a means of patho- 

 logical investigation, its relation to the 

 practice of medicine and to jurispru- 

 dence, and special responsibilities aris- 

 ing 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 scien- 

 tifically demonstrate the immortality of 



the soul within a year,' that it is due to 

 the facts bearing upon the choice be- 

 tween materialism and spiritism to say 

 that I have never made any such pro- 

 fessions 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 preten- 

 sions 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 ob- 

 tained by M. Bafllaud, of the Toulouse 

 Observatory, France, from recent obser- 

 vations of the annular nebula in Lyra 

 and comparisons with photographs taken 

 in 1S90. 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 photo- 

 graphs, giving it the aspect of a true 

 star, and greater brightness in the cen- 

 tral 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 phe- 

 nomena. 



The Chicago Manual-Training School, 

 which is said to be the first independent 



