334 ELECTRICITY DURING THE NINETEENTH CENTURY. 



analogous and clost'ly related phenomena of magnetism had already- 

 found an important application in the navigator's compass. 



The simplest facts of electro-magnetism, upon which much of the 

 later electrical developments depend, remained entirely unknown until 

 near the close of the first (juarter of the nineteenth century. Mag- 

 netism itself, as exempliiied in loadstone or in magnetized iron or 

 steel, had long before ])een consistently studied by Dr. Gilbert, of 

 Colchester. England, and in U'AH) his great work, De Magnete, was 

 pul)lished. It is a first example, and an excellent on(\ too, of the 

 application of the inductive method, so fruitful in after years. The 

 restraints which' a superstitious agi' had imposed upon nature stud}^ 

 were gradually removed, and at the beginning of the century just past 

 occasional decided encouragement ]>egan to be given to ])hysi(al 

 research. It was this condition wliich put into the hands of llumpluy 

 Diivy, of the Royal Institution in London, at the opening of the cen- 

 tury, a voltaic battery of some 250 pairs of plates. With this a 

 remarkal)ly fruitful era of electric discovery })egan. In 1802 Davy 

 first showed the electiic arc or *' arch '' on a small scale between pieces 

 of carbon. He also laid the foundation for futui'e electro-chemical 

 work ])y decomposing l)y the batt(M"v current potash and soda, and thus 

 isolating the alkali metals potassium and sodium for the first time. 

 This Avas in 1807, and the result was not only greatly to advance the 

 youthful science of chemistry, but to attract the attention of the world 

 to a new power in the hands of the scientific worker, the electric cur- 

 rent. A fund was soon sul)scribed by "a few zealous cultivators and 

 patrons of science" interested in the discovery of Davy, and he had at 

 his service in 1801 no less than 2,000 cells of voltaic battery. With 

 the intense currents obtained from it he again demonstrated the won- 

 'derfid and brilliant phenomenon of the electric arc by closing the cir- 

 cuit of the battery through terminals of hard-wood charcoal and then 

 separating them for a short distance. A magnificent arch of flame was 

 maintained between the separated ends, and the light from the charcoal 

 pieces was of dazzling splendor. Thus was born into the world the 

 electric arc light, of which there are now hundreds of thousands burn- 

 ing nighth" in our countr}' alone. 



Dav}^ probably never imagined that his ])rilliant experiment would 

 soon play so important a part in the lighting of the world. He may 

 never have regarded it as of any practical value. In fact, man}' 3^ears 

 elapsed before any further attempt was made to utilize the light of the' 

 electric arc. The reason for this is not difiicult to discover. The bat- 

 teries in existence were crude and gave onl}' their full power for a very 

 short time after the circuit was closed. They were subject to the very 

 serious defect of rapid polarization, whereby the activity was at once 

 reduced. A long period elapsed before this defect was removed. 

 Davy, in his experiments, had also noted the very intense heat of the 



