January 15, 1904.] 



SCIENCE. 



99 



and his predictions were verified. While 

 all of Mendele Jeff's predictions, specific and 

 tacit, have not been verified, some have. 

 Ramsay* and others, without a periodic 

 guide, predicted certain of the inert gases, 

 which predictions have been verified. 



Victor Meyer, in speaking of the comple- 

 tion of the Mendele jeff table, calls attention 

 to the summing up of one hundred ele- 

 ments, from which it appears that 258 

 would be the limit to our atomic mass 

 equivalents. I am not prepared positively 

 to contradict such a conclusion at the pres- 

 ent time, but there are reasons for thinking 

 otherwise. 



Clarkef has shown that the mean density 

 of the earth, 5.5 to 5.6, is more than double 

 that of the rocky crust, and 'the difference 

 may be accounted for as a result of pres- 

 sure, or by supposing that, as the globe 

 cooled, the heavier elements accumulated 

 towards the center.' While it is quite im- 

 possible to judge of the order of this intra- 

 mundane pressure, I am not aware of such 

 marked changes being brought about in the 

 specific gravities of the heavier solid ele- 

 ments of their compounds, either by pres- 

 sure, allotropic or isomeric changes, except 

 the cerebral argentaurum of the late S. H. 

 Bmmens. X The examinations of volcanic 

 dusts by Hartley,§ Fleet || and others ap- 

 pear to contradict the latter explanation, 

 although we are unable to state the depth, 

 perhaps within the shell considered by 

 Clarke, at which volcanoes begin their bois- 

 terous activity. AVhile awaiting a fulfiU- 

 ■ * Address before the Chemical Section, British 

 Association, Toronto meeting (1898). 



t ' The Relative Abundance of the Chemical Ele- 

 ments,' F. W. Clarke, read before the Philosoph- 

 ical Society of Washington, October 26, 1899; 

 Chem. Neu-s, 62, 31. 



J Argentaurum papers published by Emmens, 

 New York. 



I Royal Society, February 21, 1901 ; Chem. 

 Kew,s, 83, 174. 



II Abstr. Proc. Geol. Soc, 1902, 117; Joiirn. 

 Chem. Soc. (Land), 81-82, ii., 518, 1902. 



ment of Martinez's* project to explore the 

 earth's center, we may offer a third solu- 

 tion, not wholly unscientific, as it can do no 

 harm, and has nought to do with any yellow 

 peril in science, namely, the existence of 

 elements with atomic weights higher than 

 those set by the silent limit of periodic 

 tables. 



' ' Most molecules — probably all — are 

 wrecked by intense heat, or, in other words, 

 by intense vibratory motion, and many are 

 wrecked by a very impure heat of the 

 proper quality. Indeed, a weak force, 

 which bears a considerable relation to the 

 construction of the molecule, can by timely 

 savings and accumulation accomplish what 

 a strong force out of relation fails to 

 achieve. ' 't 



As hinted at in the earlier portion of 

 this undul.v prolonged address, many 

 have theorized as to the ultimate composi- 

 tion of matter. The logic of Larmor'sJ 

 theory, involving the idea of an ionic sub- 

 stratum of matter, the support of J. J. 

 Thomson 'sg experiments, the confinnation 

 of Zeeman's phenomenon, the emanations 

 of Rutherford, Martin 's|| explanations, can 

 not fail to cause credence in the correctness 

 of Crookes's idea of a fourth state of 

 matter.^ In the inaugural address as 

 president of the British Association (1898), 

 he acknowledges in the mechanical con- 

 struction of the Roentgen ray tubes a sug- 

 gestion by Silvanus Thompson to use for 

 the anticathode a metal of high atomic 

 weight. Osmium and iridium were used, 

 thorium tried, and in 1896 Crookes ob- 

 tained better results with metallic uranium 

 than platinum. 



These and the facts that most of the ele- 

 ments with high atomic weights, in fact 



* ' La Nature,' 8c. Am. Sup., 21, 546, 1886. 



\ Tyndall in Longman's Magazine. 



X Fhil. Mag., December, 1897, 506. 



I Phil. Mag., October, 1897, 312. 



II Chem. News, 85, 205, 1902. 

 f Phil. Trans., II., 1881, 433. 



