IV. 



ELECTRICITY AS A LABORATORY SERVANT. 



A. D. Cole. 



Electricity was born in the laboratory. It passed its child- 

 hood there and we watched the development of its unsuspected 

 powers with ever increasing interest and expectation. Now it 

 has become a man and gone forth from its early home to strive 

 mightily in the world's work. We may profitably open our 

 doors to it again that it may assist us in carrying on 

 the general work of the laboratory. We may not set it apart 

 for study in the physicist's work-room, but treat it as a conven- 

 ient agent for doing many kinds of work in chemical, geological 

 and biological as well as physical laboratories. 



Think of the numerous uses for motors under perfect con- 

 trol ; the physicist desires to rotate his whirling table, his 

 color discs and his sirens by their means ; the chemist would 

 use them to exhaust for his filtrations, stir solutions in his 

 absence, crush his ores and grind his powders ; the lithologist 

 desires them for polishing his rock sections and dressing his 

 specimens. Then we all want electric light, some for project- 

 ing lanterns, some for illuminating microscopic slides, some for 

 exploring cavities and organs otherwise incapable of illumina- 

 tion, some for photographic dark-rooms. And how numerous 

 the possibilities suggested by the fact, that we can electrically 

 generate hesitjusl ivJiere we want it and keep it away from neigh- 

 boring parts which we desire to keep cool. The physicist must 

 have it for measuring coefficients of expansion, the chemist for 

 heating one vessel within another that must be kept cooler than 

 itself, also for distilling highly inflammable substances ; the 

 biolocrist finds it convenient for his incubator and his cultures of 



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