Maech 25, 1904.] 



SCIENCE. 



483 



but rather the power which it confers upon 

 him of devoting his energies to those phases 

 of the subject which are under investiga- 

 tion, those topics which for the time being 

 have become really fundamental. 



Among other improvements in this direc- 

 tion there came after the dynamo, in rapid 

 succession, like a host of beneficent corol- 

 laries, the electric motor, the arc lamp, the 

 incandescent lamp, the storage cell, the 

 powerful magnetic field, the transformer, 

 the electric furnace, the electrolytic inter- 

 rupter, the oscillograph, each opening up 

 hitherto-undreamed-of possibilities in the 

 way of demonstration for elementary stu- 

 dents and of investigation for advanced 

 students. 



I shall not detain you further to illus- 

 trate a point which is, perhaps, more fa- 

 miliar to many of you than to me. Let 

 me only mention, as opening up new possi- 

 bilities for the student, the platinum ther- 

 mometer, the high temperature mercury 

 thermometer, the Rowland grating, the 

 Wallace-Thorpe replica, the interferometer, 

 Jena optical glass, quartz ware, the cheap 

 production of aluminium, platinum mir- 

 rors, isochromatic dry plates, and so on 

 almost without end. 



But if these devices have aided under- 

 graduate instruction, what shall we say of 

 the student advanced to the point where 

 he is ready to take up a piece of research? 

 For him they have rendered problems 

 soluble, by the hundred, which previously 

 lay in the region denoted by Mr. Gladstone 

 as ' outside of practical politics. ' 



But best of all the discoveries which the 

 last generation has made concerning the 

 merely mechanical side of teaching physics 

 is the fact that practically all the funda- 

 mental — and many even of the more re- 

 condite — principles may be demonstrated 

 with apparatus of the titmost simplicity. 

 One condition only stands between the 

 simple material outfit and success, namely, 



an instructor who is so thoroughly master 

 of the subject and of the situation that he 

 will see that the stiident gets from his out- 

 fit all the information and all the training 

 intended. The older any man becomes, the 

 more he admires simplicity, and especially 

 the simplicity of nature (our ever-present 

 model), of whom Fresnel remarked: 'She 

 never balks at the difficulties of analysis, 

 but always hesitates to employ methods 

 which are complicated.' 



The nations of light and leading have 

 made a capital discovery just at the close 

 of the nineteenth century; they have just 

 awakened to the fact that they can 'go 

 in and possess the land' more easily when 

 they have at home an intelligent rank and 

 file, an educated parliament, a scientific 

 government, a free and happy electorate. 

 So also in the teaching of physics a capital 

 discovery has, I think, been recently made 

 in the fact that armament is not every- 

 thing. No number of expensive and 

 elaborate demonstrations, no striking ex- 

 hibitions of machinery can ever replace 

 the simple experiment, the lucid and or- 

 derly presentation of phenomena, the dis- 

 tinct eifort made by the student to grasp 

 the essential principle, or the conscious 

 effort at accurate observation and judg- 

 ment called forth by an ambition to get 

 from a simple device the best attainable 

 result and the simplest possible point of 

 view. There is danger in any instrument 

 when it becomes so perfect and so accurate 

 that the young man who is working with 

 it is tempted to degenerate into an 'organ- 

 grinder.' The accuracy in a laboratory 

 should not all be confined to its machinery ; 

 some should be left for the judgment. 



It was, therefore, no small step in ad- 

 vance when the instructor came to see 

 clearly that all he can ask of a piece of 

 apparatus is that it shall be capable of 

 yielding the results which he demands of 

 the student, and conversely that he can 



