SIX LECTURES ON LIGHT. 



out from view those workers who are engaged 

 in the quieter ami profounder business of 

 original investigation. " 



Take the electric telegraph as an example, 

 which has been repeatedly forced upon my 

 attention of late. I am not here to attenuate 

 in the slightest degree the services of those 

 who, in England and America, have given 

 the telegraph a form so wonderfully fitted for 

 public use. They earned a great reward, and 

 assuredly they have received it. But I should 

 be untrue to you and to myself if I failed to 

 tell you that, however high in particular re- 

 spects their claims and qualities may be, prac- 

 tical men did not discover the electric tele- 

 gn.ph. The discovery of the electric telegraph 

 implies the discovery of electricity itself, and 

 the development cf its laws and phenomena. 

 Such discoveries are not made by practical 

 men, and they never will be made by them, 

 because their minds are beset with ideas 

 which, though of the highest value from one 

 point of view, are not those which stimulate 

 the original discoverer. 



The ancients discovered the electricity of 

 amber ; and Gilbert, in the year 1600, ex- 

 tended the force to other bodies. Then fol- 

 lowed other inquirers, your own Franklin 

 among the number. But this form of elec- 

 tricity, though tried, did not come into use 

 for telegraphic purposes. Then appeared the 

 great Italian, Volto, who discovered the 

 source of electricity, which bears his name, 

 and applied the most profound iasight and 

 the most delicate experimental skill to its de- 

 velopment. Then arose the man who added 

 to the powers of his intellect all the graces of 

 the human heart, Michael Faraday, the dis- 

 coverer of the great domain of magneto- 

 electricity. CErsted discovered the deflection 

 of the magnetic needle, and Arago and Stur- 

 geo:i the magnetization of iron by the elec- 

 tric current. The voltaic circuit finally found 

 its theoretic Newton in Ohm, while Henry, 

 of Princeton, who had the sagacity to recog- 

 nize the merits of Ohm while they were still 

 decried in his own country, was at this time 

 in the van of experimental inquiry. 



In the works of these men you have all 

 the materials employed at this hour in all the 

 forms of the electric telegraph. Nay, more ; 

 Gauss, the celebrated astronomer, and Weber, 

 the celebrated natural philosopher, both pro- 

 fessors in the University of Gottingen, wish- 

 ing to establish a rapid mode of communication 

 between the observatory and the physical 

 cabinet of the university, did this by means 

 of an electric telegraph. The force, in 

 short, had been discovered, it- laws investi- 

 gated and made sure, the most complete 

 mastery of i's phenomena had been attained, 

 nay, its applicability to teleg.aphic purposes 

 demonstrated, by men whose sole reward for 

 their labors was the noble joy of discovery, 

 and before your practical men appeared at 

 all upon the scene. 



Are we to ignore all this ? We do so at 



our peril. For I say agaia, that, behind all, 

 your practical applications, there is a region 

 of intellectual action to which practical men 

 have rarely contributed, but from which they 

 draw all their supplies. Cut them off from 

 this region, and they become eventually help- 

 less. In no case is the adage truer, '"Other 

 men labored, but ye are entered in o their 

 labors," than in the case of the discoverer 

 and the applier of natural truth. But now a 

 word on the other side. While I say that 

 practical men are not the men to make the 

 necessary antecedent discoveries, the cases 

 are rare in which the discoverer knows how 

 to turn his labors to practical account. Dif- 

 ferent qualities of mind and different habits 

 of thought are needed in ;he two cases; and, 

 while I wish to give emphatic utterance to 

 the claims of those whose claims, owing to 

 the simple fact of their intellectual -elevation, 

 arc often misunderstood, I am not here to 

 exalt the one class of workers at the expense 

 of the other. They are the necessary supple- 

 ments of each other; but remember that one 

 class is sure to be taken care of. All the ma- 

 terial rewards of society are already within 

 their reac.i; but it is at our peril that we neg- 

 lect to provide opportunity for those studies 

 and pursuits which have no such rewards, 

 and from which, therefore, the rising genius 

 of the country is incessantly tempted away. 



Pasteur, one of the most eminent members 

 of the Institute of Fiance, in accounting for 

 the disastrous overthrow of his country and 

 the predominance of Germany in the late 

 war, expresses himself thus: " Few persons 

 comprehend the real origin of the marvels of 

 industry and the wealth of nations. I need 

 no further proof of this than the employment, 

 more and more frequent in official language, 

 and in writing of all sorts, of the erroneous 

 expression applied science. The abandon- 

 ment of scientific c reers by men capable oi" 

 pursuing them with distinction was recently 

 complained of in the presence of a minister 

 of the greatest talent. This statesman en- 

 deavored to show that we ought not to be 

 surprised at this result, because /;/ our day 

 the reign of theoretic science yielded place to 

 tJiat of applied science. Nothing coald bs 

 more erroneous than this opinion, nothing, I 

 venture to say, more dangerous, even to 

 practical life, than the consequences whicn 

 might How from these words. They have 

 rested on my mind as a proof of the imperi- 

 ous necessity of reform in our superior edu- 

 cation. There exists no category of the 

 sciences to which the name of applied science 

 could be given. ll'e have science, and the 

 applications of science which are united to- 

 gether as the tree and its .\ruit." 



And Cuvier, the great comparative anato- 

 mist, writes thus upon the same theme- 

 "These grand practical innovations are the 

 mere applications of truths of a higher order, 

 not sought with a practical intent, but which 

 were pursued for their own sake, and solely 



