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the hypothesis which bridges over the gulf that separates the known 

 from the unknown. It may be only a phantom ; it may prove to 

 be a reality. But as these sciences relate to matters of fact which, 

 if not directly, may be made indirectly cognizable by the external 

 senses, they afford us peculiar facilities, far beyond what exist in other 

 departments of knowledge, of testing the accuracy of the views which 

 the imagination has suggested, so that we may at once determine 

 when it has been too excursive, and, if it has been so, call it back to its 

 right place. There may be instances of mere accidental discovery ; 

 but, setting these aside, the great advances made in the inductive 

 sciences are, for the most part, preceded by a more or less probable 

 hypothesis. The imagination, having some small light to guide it, 

 goes first. Further observation, experiment, and reason follow. 

 Thus, for example, it had been long suspected that there is some 

 sort of relation between electricity and magnetism. Much thinking 

 on the subject had strengthened this suspicion in the mind of Oersted. 

 Still it was but a hypothesis, and might even now have been re- 

 garded by many as no better than a dream, if it had not been that 

 in the year 1820 the Danish philosopher devised the experiments 

 which demonstrated the law of reciprocity between an electric current 

 and the magnet, and the identity of the two forces. As an instance 

 of an opposite kind, I may refer to the doctrine of phlogiston as pro- 

 pounded by Stahl. While the art of chemical experiment was im- 

 perfectly understood, that doctrine was very generally received as 

 affording a true explanation of the phenomena of combustion. But 

 no sooner had Lavoisier and his friends introduced a more accurate 

 mode of experiment by weight and measure, than it was proved to 

 have no foundation in reality, and consigned to the same place in the 

 history of science with epicycles and vortices and animal spirits. 



But the effect of some kind of instruction in the physical sciences 

 being recognized as an essential part of a liberal education, may be 

 contemplated under another point of view. Except in the case of 

 particular professions or occupations, a profound knowledge of these 

 subjects is not required ; but there is no situation in life in which some 

 knowledge of them may not be turned to a good account. Is there 

 any country gentleman or farmer who might not derive advantage 

 from knowing something of vegetable physiology and chemistry? 

 would not a knowledge of scientific botany make a man a better 



