May 15, 1903.] 



SCIENCE. 



779 



tion by means of gaseous hydrogen chlo- 

 ride, fusing with alkaline hj^droxides, 

 sodium dioxide, etc. The details will be 

 given in the full papers when published.* 

 Suffice it to say that we have succeeded in 

 obtaining a preparation, which has lost 

 entirely the absorption line ^ 443 and an- 

 other, very small in amount, which shows 

 only that line. The oxide is bright green 

 when heated in the air. The work of 

 Crookes and Dennis isthus verified by en- 

 tirely novel methods. Drossbaeh reports 

 the existence of an element in monazite 

 sand with an atomic weight of 100, that is, 

 eka-manganese, but it is discredited by 

 Urbain. 



It may be interesting at this point to 

 call the attention of the scientific men of 

 America to the fact that from the locality, 

 Ytterby, where cerite was found, four ele- 

 ments, yttrium, erbium, terbium and ytter- 

 bium, have secured a name. From the 

 occurrence of samarskite and monazite 

 (Mitchell and McDowell and other counties 

 in North Carolina and Brazil), which con- 

 tain most of these rare earths and have 

 furnished so much of the material for the 

 researches, not a single element is named, 

 except the tentative carolinium, which will 

 now receive attention. 



The other rare earths to which I wish to 

 direct your indulgent attention in a few 

 words are those which possess radio-activ- 

 ity, a property accidentally rediscovered 

 by Beequerel. It may be remarked that 

 Sir George Stokes fifty years ago addressed 

 the physicists of the British Association on 



* I have been assisted in the numerous re- 

 searches barely summarized in this address by 

 Messrs. J. E. Mills, R. O. E. Davis, J. W. Turren- 

 tine, James Thorpe, Eeston Stevenson, W. O. 

 Heard, Hazel Holland, E. B. Moss, H. H. Bennett, 

 Geo. P. Catlell and F. H. Lemly. The separate 

 papers will shortly be published. Three grants of 

 fifty dollars each have been made by the American 

 Association for the Advancement of Science to aid 

 in the work on the rare earths. 



the curious action of certain bodies in 

 emitting light .at ordinary temperatures. 

 Little was then known of the phenomenon 

 of fliiorescence. There is not time to at- 

 tempt a discussion of the origin and nature 

 of radio-activity. It appears that our 

 satisfactory Maxwellian theory of the pro- 

 gression of ethereal stresses may yet be 

 harmonized with the older corpuscular 

 view of Descartes and Newton by the re- 

 cent elegant researches of Beequerel, J. J. 

 Thomson, Rutherford, Giesel and others. 



M. and Mme. Curie have been pioneers 

 in utilizing this physical activity, which 

 serves to detect the presence of minute 

 amounts of certain elements contaminating 

 hitherto well-defined bodies. J. J. Thom- 

 son, in his recent extremely interesting 

 address at Belfast, brings out a point de- 

 manding the chemist's closest attention, 

 namely, that the radio-activity is five thou- 

 sand times as delicate as the spectroscope, 

 it matters not whether the arc, spark, ab- 

 sorption or phosphorescent spectrum be 

 made use of. 



By prolonged fractionation the Curies 

 separated radium from barium salts. 

 Demarcay has prepared the spectrograph 

 showing the characteristic lines of the ele- 

 ment, while Madame Curie determined its 

 atomic weight (225). It fits beautifully 

 in Mendeleeff's table. The Curies have 

 also announced polonium, or the active 

 constituent of bismuth. Uranium appears 

 to have been the first to shi^w this property, 

 as noted by Beequerel. Actinium, it seems, 

 is the elusive body found in pitchblende by 

 Curie, and appears to be the same as 

 Crookes' uranium X. 



Chroustsehoff a dozen years ago an- 

 nounced that thorium contained another 

 element, which he called russium. I have 

 been unable to secure a copy of this paper 

 or even to learn where it appeared. I am 

 informed by Professor Mendeleeff, who 



