PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 341 



plex bodies, quite capable under proper provocation of such 

 disintegration as is shown by radio-active substances. 



While many well-known phenomena have pointed for years 

 to the probability that the atom, whether it could be broken or 

 not by human power was really very complex, yet we have for 

 the first time a definite constituent separated and isolated, and 

 a first step made toward studying directly the structure 

 of the atom itself. J. J. Thomson, Rutherford, Bohr, and 

 others have devised ingenious models of atoms, which meet more 

 or less perfectly the experimental conditions, and furnish valua- 

 ble suggestions for future work. 



We have been obliged to pass over, almost without mention, 

 various researches which have enlightened one or another side 

 of our subject, such as the work of Hertz on electric waves, 

 which, of great theoretical interest in itself, gave rise to wireless 

 telegraphy, the subject of ionisation in solutions, the behavior 

 of incandescent gases in a magnetic field, known as the Zeeman 

 effect, the whole subject of photo-electricity, the phenomena of 

 positive rays, discovered by Goldstein, from which Sir Joseph 

 Thomson has recently developed his fascinating method of 

 chemical analysis. 



But we have passed in review, however hastily and imper- 

 fectly, the two lines of physical research which make up by far 

 the most important work of the past twenty-five years. They 

 traverse the most fundamental thinking of the previous century, 

 and lead us farther into the complexities of natural phenomena 

 than we have looked before. Yet it is interesting to compare 

 this modern work, so delicate and minute, so remote from hu- 

 man life, with the great generalizations of the nineteenth cen- 

 tury. However striking these phenomena are, they seem rather 

 thin and shadowy by the side of those other powerful and solid 

 achievements. But this shows us how truly we have gone into 

 a new field. These things are yet in their beginnings. Whither 

 they will lead we cannot yet tell, though it seems certain that 

 they will lead far, or whether they will develop as great practical 

 value as that previous work. Faraday's induced current, after 

 all, was but a feeble creature at first. But it matters little at 



