THE GROWTH OF SCIENCE IN THE NINETEENTH CENTURY. 177 



nearly " and ' ' the almost. " Nature never is. It is not her way to call the 

 same two things which differ, though the difference may be measured 

 by less than a thousandth of a milligram or of a millimeter, or b}^ any 

 other like standard of minuteness. And the man who, carrying the 

 ways of the world into the domain of science, thinks that he may treat 

 nature's differences in any other way than she treats them herself, will 

 ffnd that she resents his conduct; if he, in carelessness or in disdain, over- 

 looks the minute difference which she holds out to him as a signet to 

 guide him in his search, the projecting tip, as it were, of some buried 

 treasure, he is bound to go astray, and the more strenuously he strug- 

 gles on the farther he will find himself from his true goal. 



In the second place, he must be alert of mind. Nature is ever mak- 

 ing signs to us; she is ever whispering to us the beginnings of her 

 secrets; the scientific man must be ever on the watch, ready at once to 

 lay hold of nature's hint, however small; to listen to her whisper, how- 

 ever low. 



In the third place, scientific inquiry, though it be preeminently an 

 intellectual effort, has need of the moral quality or courage — not so 

 much the courage which helps a man to face a sudden difficulty as the 

 courage of steadfast endurance. Almost every inquiry, certainly every 

 prolonged inquir}", sooner or later goes wrong. The path, at first so 

 straight and clear, grows crooked and gets blocked; the hope and 

 enthusiasm, or even the jaunty ease, with which the inquirer set out, 

 leave him, and he falls into a slough of despond. That is the critical 

 moment calling for courage. Struggling through the slough, he will 

 find on the other side the wicket gate opening up the real path; losing 

 heart, he will turn back and add one more stone to the great cairn 

 of the unaccomplished. 



But, I hear some one say, these qualities are not the peculiar attri- 

 butes of the man of science; they may be recognized as belonging to 

 almost everyone who^ has commanded or deserved success, whatever 

 may have been his walk of life. That is so. That is exactly what 

 I would desire to insist, that the men of science have no peculiar vir- 

 tues, no special powers. They are ordinar}^ men, their characters are 

 common, even commonplace. Science, as Huxley said, is organized 

 common sense, and men of science are common men drilled in the 

 ways of common sense. For their life has this feature. Though in 

 themselves they are no stronger, no better than other men, they pos- 

 sess a strength which, as I just now urged, is not their own, but is that 

 of the science whose servants they are. Even in his apprenticeship the 

 scientific inquirer, while learning what has been done before his time, 

 if he learns it aright, so learns it that what is known may serve him 

 not onl}^ as a vantage ground whence to push off into the unknown, 

 but also as a compass to guide him in his course. And when fitted for 

 his work he enters on inquir}^ itself, what a zealous, anxious guide, 

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