14 



SCIENCE. 



[N. S. Vol. XXIV. No. 601. 



more accurate, but rather to use all the 

 powers the past has conferred on the hu- 

 man spirit to win new power. The past 

 gives the scientific investigator his lever 

 and the present his fulcrum; but his work 

 is to take effect on the future, and is to 

 give him or his successors a stronger lever 

 and a better placed fulcrum. As a rule, 

 scientific research is carried on with no 

 public observation, and as silently as nature 

 elaborates and throws out the mantling 

 verdure of spring-, but on an exceptional 

 occasion like this, and in a country which 

 has already reaped great benefits from the 

 endowment of institutions of education and 

 charity by public-spirited persons, it is 

 fitting that the beneficent work of the 

 scientific investigator should be accurately 

 described, and commended to the favor of 

 an enlightened public opinion. 



Let us first consider what mental habits 

 and powers the scientific investigator needs 

 to have acquired and to keep in exercise, 

 or in other words what sort of a mind the 

 investigator ought to have. In the first 

 place, he needs the faculty and the habit 

 of determining and grasping facts, and 

 then verifying and digesting them. He 

 must next be capable of conceiving hy- 

 potheses which will connect his facts, or 

 explanations that will group them or ar- 

 range them in a series. These hypotheses 

 or explanations will come to him as results 

 of reflection or of imaginative scheming; 

 in the common phrase, ideas will occur to 

 him. A preconceived idea may be a great 

 power in experimental researches ; but the 

 inquirer must have the habit of pursuing 

 to verification or disproof all such ideas. 

 He must test them by new experiments 

 contrived for that purpose. He must ex- 

 haust all the adverse hypotheses which 

 come to his mind. He must always keep 

 in the road that leads to truth, although 

 he does not know just where the truth lies. 



If through the play of his imagination he 

 gets off the right road, his rigorous experi- 

 mentation must bring him back to the safe 

 path of the inductive method. He must 

 possess patience and reserve, but also en- 

 thusiasm and a capacity for eager specula- 

 tion. Science has often profited by a sug- 

 gestive theory, which was far from being 

 true. Indeed, the history of scientific 

 progress is full of these profitable theories, 

 which have been abandoned one after the 

 other; and in all probability the series of 

 such theories will prove to be infinite. 

 Sometimes theories long forgotten are taken 

 up again after the defeat of the later the- 

 ories which caused the forgetting of the 

 earlier. However it may be in theology, 

 it is quite certain that in science there is 

 as yet no such thing as final truth. Ac- 

 cordingly, investigators in any science need 

 an unusual perspicacity or clear-sighted- 

 ness in regard to its theories; they need, 

 each in his own field, a full knowledge of 

 the work already done, and a clear percep- 

 tion of the bearings of the most recent dis- 

 coveries. This perspicacity is in some 

 measure a natural gift; but it is also a 

 faculty capable of a high degree of train- 

 ing. It sees clearly the approximate truth 

 already discovered, and goes forward to 

 obtain a closer approximation. 



The general features of scientific re- 

 search are similar in all fields, although 

 each kind has its peculiar difiiculties. The 

 field of the individual inquirer need not 

 necessarily be wide; although the progress 

 of many sciences is often contributory to 

 the progress of one, and that investigator 

 has a great advantage who is capable of 

 seeing clearly the bearings of new discov- 

 eries in kindred sciences on the particular 

 inquiry he has in hand. It is all-impor- 

 tant, however, in all fields, that the investi- 

 gator should be capable of seizing on the 

 essential parts of the inquiry— that is, on 



