294 PERSONAL PREPARATION FOR RESEARCH. 



Knowledge begets knowledge, as wealth begets wealth, 

 and he who possesses mifch can with the greater facility 

 obtain more. Eeading imparts to us much more extensive, 

 varied, and useful knowledge than observation, because by 

 means of it we obtain the results o^ the observation of 

 almost innumerable minds ; it also yields us a knowledge 

 not only of facts, but also of comparisons, general ideas, 

 inferences, imaginations and hypotheses, ready formed. A 

 thoughtful mind becomes original in the very act of read- 

 ing and study. Whilst reading, we should learn how to 

 skip with judgment, selecting and taking notes of all the 

 fundamental truths with suitable illustrations, and such 

 others only as may be of service. 



One of the most important qualifications of a scientific 

 discoverer, viz., rapid scientific insight, depends essentially 

 upon the possession of extensive knowledge, and especially 

 upon a knowledge of great scientific principles and their 

 relations to each other. Every fact and every discovery 

 casts a light beyond itself, and the extent to which this 

 light is perceived depends upon the man. Had Galvani 

 possessed as extensive and accurate knowledge of electricity 

 as Volta did, he would probably not have referred the con- 

 tractions of the frog's muscles to his supposed ' animal 

 electricity,' but have perceived that the source of the 

 current was the contact of dissimilar metals with liquids, 

 and that the limb of the frog was only a sensitive indicator 

 of dynamic electricity. 



A scientific investigator requires to be acquainted not 

 only with his own particular subject, but also to some 

 extent with the leading principles of other sciences, because 

 all the forces of nature are more or less connected together, 

 and their influences are liable to affect in various ways the 

 phenomena of every experiment. Scarcely a single phe- 

 nomenon can be completely explained without a knowledge 



