SKETCH OF FRANK WIGGLES WORTH CLARKE. 117 



January, 1873 (Volume II), on Evolution and the Spectroscope, 

 showed that the evolution of the planets from nebulae was possibly 

 accompanied by an evolution of the chemical elements. This was 

 nearly a year in advance of Lockyer's first paper suggesting the same 

 general view. The discussion of this subject was taken up again in 

 the eighth volume of the Monthly (February, 1876), in an article, 

 Are the Elements Elementary? in which the author, after showing- 

 how subtle connections significant of unity run through them all, 

 inquired : " If the elements are all in essence one, how could their 

 many forms originate save by a process of evolution upward? How 

 could their numerous relations with each other, and their regular serial 

 arrangements into groups, be better explained? In this, as in other 

 problems, the hypothesis of evolution is the simplest, most natural, and 

 best in accordance with facts. Toward it all the lines of argument 

 presented in this article converge. Atomic weights, specific volumes, 

 and spectra, all unite in telling the same story, that our many ele- 

 ments have been derived from simpler stock." These views were 

 admitted to be speculative but not baseless. " Science is constantly 

 reaching forward from the known to the unknown, partly by careful 

 experiment and partly by the prophetic vision of thought." Then, 

 speculation upon such questions " is not altogether unprofitable. The 

 time spent in conjectures and surmises is not wholly wasted, for 

 it is impossible to follow up any of the lines of thought thus opened 

 without reaching some valuable suggestions which may pave the 

 way to new discoveries. New truth, in one direction or another, is 

 sure to be reached in the long run. So, then, we may proceed to 

 theorize in the most barefaced manner without entirely quitting 

 the legitimate domain of science." An article on The Present 

 Status of Mineralogy, in the thirty-second volume of the Month- 

 ly, presents the mutual bearings of that study and chemistry and 

 geology. 



Professor Clarke contributed the chapter Element to the last 

 edition of Watts's Dictionary of Chemistry. He was made president 

 of the Washington Chemical Society in 1885, and of the Philo- 

 sophical Society of Washington in 1896. He organized and had 

 charge of Government exhibits, on behalf of the Department of the 

 Interior, at the expositions of Cincinnati, Chicago, Atlanta, Nash- 

 ville, and Omaha. He is a corresponding member of the British 

 Association, of the Edinburgh Geological Society, and of the New 

 York Academy of Sciences. 



