THERE have been from time to time during the century past some remarkable discoveries destined to cause profound changes in human thought and mode of life . Some of these have become so quickly and firmly incorporated in our environment that we have hardly realized their origin and rapid development . In theoretical and applied electricity are some of the most striking examples of such developments, having wrought such wonderful results that one can hardly realize their ramifications .
Measured in terns of the duration of human history, all electrical knowledge is recent and most of the practical applications were made within the memory of those who are near to man's allotted three score years and ten . In Denmark there has just been celebrated the one hundredth anniversary of Oersted's discovery of the relationship between electric and magnetic phenomena . A few years after Oersted's work, Henry and Faraday laid the foundation for the marvels to be accomplished in applied electricity. Less than fifty years ago the first power motor made in America was completed and one of the designers is still living-Man y of the pioneers in the development of the arc and the incandescent lamp and of the telephone are still active .
Twenty-five years ago this month there was announced a new wonder, the culmination of a long series of experiments, the starting point of a new line of endeavor, giving rise to concepts, unrivalled in scope and daring, and, curiously enough, resulting in theories strangely related to those of the master mind whose honored name is borne by this society .
A careful and well-trained observer, already well known in his chosen field, Rontgen not only announced a type of radiation whose existence had not been suspected but he described, with *Presented at a meeting of the Section of Physics and Chemistry held