ACADEMY OF SCENCES] GILBERT'S WORK 291 



heard another address on "Special processes of research," at Philadelphia, in December, 1886, 

 in which the use of various graphic devices as a means of furthering investigation was considered. 

 The public lecture on the "History of Niagara River," delivered at the Toronto meeting of the 

 American Association for the Advancement of Science in 1889, also deserves listing here, as it 

 was of high presidential quality. The address on "Continental problems" delivered before 

 the Geological Society of America, at Ottawa, in December, 1892, was unlike the others in 

 dealing chiefly with unsolved problems; one of its phrases, "go behind the postulates," deserves 

 to be here again brought to the attention of every investigator. The address on the "Moon's 

 face," delivered before the Philosophical Society of Washington in December, 1892, and here 

 abstracted in an earlier chapter, was notable for the originality and ingenuity of its specidations 

 in an astronomical problem, as well as for the minute study of lunar topography on which it 

 was based, and for the amount of experiment by which its argument was supported. If this 

 study be regarded as a trespass on the field belonging to astronomers, it shoidd be remembered 

 that Gilbert openly announced himself as "an advocate of the principle of scientific trespass," 

 as quoted in a preceding section. An address before the Geological Society of Washington 

 on the "Origin of hypotheses," in December, 1895, exhibits a remarkable capacity in main- 

 taining a suspended judgment and suggests strongly that the author's interest in the mental 

 methods of investigation was as great as, if not greater than, in the results gained; such was 

 surely the case in this instance, for no positive results were here reached, yet the path followed in 

 the attempt to reach them is described in detail and in such a way as to have delighted a critical 

 audience. "Rhythms and geologic time," a presidential address before the American Associa- 

 tion, at New York, in 1900, was a gradually developed exhortation in favor of a new lineof research 

 with the object of determining the duration of geologic ages. This was followed nine years 

 later by the seventh and last address, on "Earthquake forecasts," reviewed in a preceding 

 chapter, where it was regarded as one of the finest if not the finest of the series, an opinion that 

 is confirmed after making the present summary. 



If any one feature of these addresses deserves praise above the others it is the even-tempered 

 and candid fair-mindedness by which they are all characterized. Next would come competence 

 of treatment, and also such clarity of statement that every paragraph reads as if its thought 

 had been easily conceived. Candor is a quality that always inspires confidence, and when it 

 is coupled with ease of handling the pair are persuasively compelling. It was particularly 

 because of the combination of these two leading qualities that Gilbert's work was so appealing 

 to his associates; and it became all the more so because he replaced the advocacy and special 

 pleading that so often weaken earnestness by a most judicial impartiality. He never over- 

 worked his evidence and never wielded an argumentative sledgehammer; his presentation was 

 extraordinarily gentle, and in its gentleness lay much of its strength. That all these fine qual- 

 ities should characterize the addresses made by one man shows that that man was possessed of 

 true wisdom in a high degree; and it must be remembered that true wisdom far outweighs 

 mere learning. 



gilbert's personal influence 



It would be a serious error to imagine that Gilbert's influence on geology and geologists is 

 to be measured chiefly by the volume of his scientific work. The manner in which his problems 

 were treated and the form in which the results were set forth impressed many a reader of his 

 reports and addresses as deeply as the results themselves. Moreover, his high personal character 

 exerted a most beneficent influence upon all who came into contact with him, and they were 

 many; for although most of his researches were carried on alone, he had abundant associations 

 with a great number of other workers not only when, first as a senior geologist and later as chief 

 geologist of the national survey, he was in official relations with its members, but for years 

 afterwards when his acquaintance was sought unofficially and his advice valued by all who were 

 fortunate enough to receive it. In his work as in his personality, the qualities of candor, fair- 

 mindedness, and impartiality were as manifest as those of patience, carefulness, and unselfish- 

 ness. He possessed that most enviable combination of force and gentleness which always 

 compels respect; his force or will-power being manifested chiefly in the control of his own actions 



