July 12, 1901.] 



SCIENCE. 



59 



Another component is similar to tlie X- 

 rays, and is probably a phenomenon of 

 the ether rather than of ordinary matter. 

 Perhaps this component is produced by the 

 action of the first component, as the X-rays 

 are produced by the action of the kathode 

 rays. For the rest no satisfactory explana- 

 tion has been given. Many of the secon- 

 dary effects seem to result from a fine dust 

 emitted from the radio-active substance. 

 Possibly there is only a single primary 

 radiation, the rest being secondary effects, 

 as the kathode rays generate the X-rays 

 and these in turn generate their complex 

 secondary radiations. 



The chemical nature of the radio-active 

 substances or elements is still little under- 

 stood, nor is it surprising when one con- 

 siders the difficulty of working with sub- 

 stances occurring in such minute quantities 

 as these. Only one new element, radium, 

 is definitely established. Hofmann and 

 Strauss thought they had isolated another 

 new radio-active element, but while still 

 claiming the new element, they now ad- 

 mit that it is not radio-active. 



The question of the source of energy in 

 these radiations is yet unanswered. Is the 

 energy potential in an unstable molecular 

 or atomic structure, or is it supplied con- 

 tinuously by outside sources ? In the first 

 case, how long will the energy last ? In 

 either case, is it a property that matter in 

 general may under proper conditions as- 

 sume, or is it, as it seems, restricted to a 

 very few peculiar elements? Heat or cold, 

 high or low pressure, has little influence on 

 the emission of the rays. Mme. Curie once 

 put forth the hypothesis that perhaps the 

 radiation is induced in the radio-active ele- 

 ments by a sort of transcendental radia- 

 tion more penetrating than the X-rays and 

 pervading all our space. Professor Geitel 

 found that if so the exciting radiations 

 penetrate easily hundreds of yards of rock, 

 for radium was still active at the bottom of 



the deepest mine to which he had access. 

 Finally, the study of the radio-active sub- 

 stances will surely lead to a better knowl- 

 edge of that which is the subject of much 

 of the physical research of to-day, the 

 intimate structure of matter. 



Geo. B. Pegram. 

 Columbia University, 

 June 21, 1901. 



THE AMERICAN ASSOCIATION FOR THE AD- 

 VANCEMENT OF SCIENCE. 



The following have completed their mem- 

 bership in the American Association for the 

 Advancement of Science during the month 

 of June. 



Dr. Francis E. Abbot, Author, 43 Larch Road, 

 Cambridge, Mass. 



Ernest Kempton Adams, Scientific Investigator, 

 455 Madison Ave., New York, N. Y. 



Harry Alexander, Elec. and Mech. Engineer, 18 

 and 20 West 34th Street, New York, N. Y. 



E. B. Alsop, Metallurgy and Engineering, 541 Wood 

 Street, Pittsburg, Pa. 



James I. Ayer, Electrician, 5 Main Street Park, 

 Maiden, Mass. 



Ealph Baggaley, engineer, Pittsburg, Pa. 



Daniel Moreau Barringer, Geologist and Mining 

 Engineer, 460 Bullitt Building, Philadelphia, Pa. 



Professor Walter B. Barrows, Prof, of Zoology, 

 Agricultural College, Michigan. 



Francis Bartlett, 40 State Street, Boston, Mass. 



James Newton Baskett, Author-Zoologist, Mexico, 

 Mo. 



Eev. John Mallery Bates, Botany, Callaway, Neb. 



Dr. Henry Harris Aubrey Beach, Physician, 28 

 Commonwealth Avenue, Boston, Mass. 



Professor Arthur E. Beardsley, Prof, of Biology, 

 State Normal School, Greeley, Colo. 



Bernhard Arthur Behrend, Civil and Elec. Engi- 

 neer, Station H, Cincinnati, Ohio. 



August Belmont, 23 Nassau Street, New York City. 



Charles W. Bennett, Geologist, Coldwater, Mich. 



Dr. Augustus C. Bernays, Specialist in Embryology, 

 Anatomy and Surgery, 3623 Laclede Avenue, St. 

 Louis, Mo. 



Solomon H. Bethea, United States Attorney, Chi- 

 cago Club, Chicago, 111. 



Dr. Leslie D. Bissell, Physics, Hotchkiss School, 

 Lakeville, Conn. 



Dr. John B. Blake, Physician, 302 Beacon Street, 

 Boston, Mass. 



