It is curious to note the introduction of the word "seems" into this passage—as the lawyers say, its appearance with a semble—while in other places, e. g., where Professor Newcomb speaks of the proposition that molecules are inelastic as my "favorite doctrine," or where he charges me (after reading my tenth chapter!) with ignorantly confounding the "abstract noun" mass with the concrete term matter, he makes no such qualification.
Having satisfied himself (no doubt before writing his article, though the conclusion is stated most explicitly toward its close) that I am in the lists as a champion of the atomo-mechanical theory and as the dogmatic defender of its fundamental propositions, he proceeds to assail these propositions, sometimes with what he seems to regard as an argument, but generally with a sneer. The contents of my introductory chapter, consisting almost exclusively of citations from the writings of Professors Kirchhoff, Helmholtz, Clerk Maxwell, Ludwig, Du Bois-Reymond, etc., he brands as "propositions in which we can trace neither coherence nor sense." The thesis that, on the basis of the atomo-mechanical theory, all potential energy is in reality kinetic—the distinct proposition of Professor P. G. Tait, who asserts it as the unavoidable consequence of the atomo-mechanical theory of gravitation—he "passes over as not even worth quoting." Similarly the doctrine of the essential passivity of matter—also a proposition of Professor Tait, whose exact words I quote on page 306 of my book—is flouted with the disdainful remark that "such words as 'active' and 'passive' have no application in the case and serve no purpose, except to produce confusion in the mind of the reader." In this way he levels his thrusts at the most eminent physicists and mathematicians of the day, laboring always under the hallucination that he is striking at me.
Among the most characteristic performances of Professor Newcomb are his strictures, already adverted to, on my substitution of the term mass for the word matter, in designation of the substratum of motion in the light of the atomo-mechanical theory. According to him, this use of the word mass is evidence of my ignorance and intellectual confusion, as well as of my "total misconception of the ideas and methods of modern science." He informs me that the word mass is "an abstract noun like length," whereas I use it "as a concrete term, and in nearly the same sense as we commonly use the word matter." And thereupon he delivers himself of a dissertation (which resembles nothing so much as a sermon of "Fray Gerundio" to his "familiars") on the necessity of using scientific terms only in accordance with their exact definitions, of ascertaining the meanings of the words mass and motion by a reference to the methods whereby they are measured, and
