SCIENTIFIC CULTURE. 527 



there is no better means of training this logical faculty than the study 

 of qualitative chemical analysis in which many of you are to eno-at^e. 

 The results of the processes of qualitative analysis are perfectly defi- 

 nite and trustworthy ; but they are only reached by following out the 

 indications of experiments which are frequently obscure, and even ap- 

 parently contradictory ; reconciling by new experiments the seeming 

 discrepancies, and, at last, having eliminated all other possible causes 

 of the phenomena observed, discovering the true nature of the sub- 

 stances under examination. The study of mineralogy affords an al- 

 most equally good practice, although in a somewhat different form. 

 By comparing carefully many specimens of the same mineral, you 

 learn to distinguish the accidental from the essential characters, and 

 on this distinction you must base your inferences in regard to the 

 nature of the specimens you may be called upon to determine. A 

 single remark occurs to me which may aid you in cultivating this sci- 

 entific logic. 



Do not attempt to reason on insufficient data. Multiply your ob- 

 servations or experiments, and, when your premises are ample, the 

 conclusion will generally take care of itself. Are you in doubt in re- 

 gard to a mineral specimen ? Repeat your observations again and 

 again, multiply them with the aid of the blow-pipe or goniometer, 

 compare the specimen with known specimens which it resembles, until 

 either your doubts are removed, or you are satisfied that you are un- 

 equal to the task ; and remember that, in many cases, the last is the 

 only honest conclusion. Are you in doubt in regard to the reactions 

 of the substance you are analyzing, whether they are really those of a 

 metal you suspect to be present ? Do not rest in such a frame of 

 mind, and, above all, do not try to remove the doubt by comparing 

 your experience with that of your neighbor : but multiply your own 

 experiments ; procure some compound of the metal, and comjjare its 

 reactions with those you have observed, until you reach either a posi- 

 tive or a negative result. Remember that the way to remove your 

 doubts is to widen your own knowledge, and not to depend on the 

 knowledge of others. When your knowledge of the facts is ample, 

 your inferences will be satisfactory, and then an unexplained phenome- 

 non is the guide to a new discovery. Do not be discouraged if you 

 have to labor long in the dark before the day begins to dawn. It will 

 at last dawn to you, as it has dawned to others before, and, when the 

 morning breaks, you will be satisfied with the result of your labor. 



Moreover, I feel confident that such exi^erience will very greatly 

 tend to increase your appreciation of the value of scientific studies in 

 training the reasoning faculties of the mind. This, as every one must 

 admit, is the best test of their utility in a scheme of education, and it 

 is precisely here that I claim for them the very highest place. It has 

 generally been admitted that mathematical studies are peculiarly well 

 adapted to train the logical faculties, but still many persons have main- 



