Samuel Tolver Preston

“ So now in the present day, in spite of the continual demolition of spiritualistic views (i. e. views of action without the intervention of matter) by advancing science, the modus operandi of gravitation remains the one outstanding subject for doubt ; and it appears to be assumed by many (much in analogy with the former question of "specific inductive capacity ") that experiments with the view to decide whether any minute specific differences might exist in the effects of gravity, dependent on structure, form, &c. ”

“ Since the successful pursuit of a research of this kind, where specific differences of a very minute character are in question, would no doubt entail considerable experimental resources, with refined and delicate apparatus, which might not be at the disposal of every one, the more therefore does it become desirable to attract general attention to the subject. The comparative dearth of discovery of any great physical principle (of a fundamental character at least) within the last few years would seem, if any thing, to call for additional zeal in experimental enterprise. ”

“ May not analogous considerations apply to gravity (still regarded by some as the result of a mystic " action at a distance") , and which, as an actual fact, now remains as the last remnant of spiritualism to be expelled from physics. In relation to this subject, Sir William Thomson, in an important development of Le Sage's theory of gravitation, published in the Philosophical Magazine for May 1873, makes the following suggestive remark, viz. ”