In October, 1899, Rowland delivered his presidential address before the society at whose head he stood. I can see now how happy he looked on that memorable occasion. Inspired by the latest revelations in Electron Physics, he prophesied what new revelations the physicists should expect in the approaching future. After describing physics as “a science above all sciences, which deals with the foundation of the universe, with the constitution of matter from which everything in the universe is made, and with the ether of space by which alone the various portions of matter forming the universe affect each other ...” he stated frankly that the physicists of America “form an aristocracy, not of wealth, not of pedigree, but of intellect and ideals.... Let us cultivate the idea of the dignity of our pursuit so that this feeling may sustain us in the midst of a world which gives its highest praise, not to the investigator in the pure ethereal physics which our society is formed to cultivate, but to the one who uses it for satisfying the physical rather than the intellectual needs of mankind.” He then pleaded that we “recognize the eras when great thoughts have been introduced into our subject and honor the great men who introduced them and proved them correct.” Then, enumerating the great problems of the physical universe, he asked: “What is matter; what is gravitation; what is ether and radiation; what is electricity and magnetism; how are these connected together, and what is their relation to heat?” Now, these are the very questions which Electron Physics has been trying to answer since that time; and this is the idealism which the American physicist has had before him ever since the days of Rowland. Electromagnetic theory of matter was the first answer to Rowland’s question: What is matter? But how about the answer to his second question: What is gravitation? If matter contains nothing but electrons, if they are really the most fundamental building stones of matter, then electricity as concentrated and stored up in the electrons can exert in addition to the well-known electrical force also a gravitational force. A somewhat novel idea, but ... why not, and why so? Einstein gives the best answer to this.