ON TERRESTRIAL MAGNETISM AND ATMOSPHERIC ELECTRICITY. 739 



It seems to be a law of Nature, ruling alike the human race and the 

 humblest microbe, that the products of an organism are fatal to itself. 

 The pessimist might infer that we are in presence of another instance of 

 the universality of the application of this law, and that pure science is 

 threatened by the very success of its pi'actical applications. The smoke 

 of our cities blots the stars from the vision of the astronomer, who, like 

 the anchorites of old, flies from the world to mountains and desert places. 

 It is only in the small hours of the morning when 



' Save pale recluse, for knowledge seeking, 

 All mortal things to sleep are given,' 



that the physicist can escape from the tremors of the traffic of a great town. 



Civilisation as it spreads by aid of the means that science has placed at 

 its disposal is destroying records, and oblitei'ating boundaries by the study 

 of which the anthropologist and the biologist might have read far back 

 into the history of our race. And now in turn the science of Terrestrial 

 Magnetism, which, on the one hand, is forging another link to connect 

 the sun and earth, and, on the other, is penetrating within the surface 

 of the globe to depths beyond the ken of the geologist, is threatened by 

 the artificial earth currents of the electric railway. 



That the crisis is serious there can be no doubt, but I will only antici- 

 pate the fuller discussion which will take place by statingthat magneticians, 

 in common with the rest of the world, recognise the great benefit which 

 electric traction confers upon the community at large. We are not so 

 foolish as to desire to embark on a crusade ai^ainst a great industrial 

 improvement of which science may well be proud ; on the other hand, we 

 must hold fast to the position that provision for the conveniences which 

 are immediately appreciated by the public shovdd be made with as little 

 damage as possible to those studies which are not less for the ultimate 

 benefit of the race. 



Had science, when the use of coal was introduced, been sufficiently 

 advanced to devise means for smokeless combustion, an evil which now in 

 more senses than one darkens the lives of the inhabitants of our great 

 towns might have been prevented from attaining its present gigantic 

 proportions. 



We are now at the beginning of another industrial epoch, which may 

 indeed, if power is transmitted from a distance on a large scale, brighten 

 our skies, but which threatens to saturate the earth beneath us with electric 

 currents. That these may interfere with the general comfort is evident 

 from the injury which has been done to underground pipes at Washington 

 and elsewhere. The construction of a powerful electrical railway in the 

 immediate neighbourhood of the laboratories of a college would interfere 

 with its efficiency, and make it impossible to perform experiments of 

 certain types. In such a case, however, something could be done by 

 arranging the experiments to suit the conditions under which they would 

 have to be performed. But in the case of a magnetic observatory no such 

 protective measures are possible. The very object of the observatory is to 

 measure the earth's field, and if that field is artificially altered no modifica- 

 tion of the methods of measurement, however ingenious, can overcome this 

 fundamental defect. I am glad to take this opportunity of acknowledging 

 that both the danger to pure science and the necessity for obviating it have 

 been acknowledged by those who are chiefly interested in the technical 

 applications of science ; and in particular that one of the principal 



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