NATURAL PHILOSOPHY 



THE ELECTRIC LIGHT. 



MUCH has been said and written upon the application of the power- 

 ful light produced by artificial electricity to the purposes of illumina- 

 tion. Many varieties of apparatus have been invented, to all of which 

 there has hitherto been some great objection. Perhaps the greatest 

 difficulty to be surmounted has been that of rendering the light steady 

 and permanent by mechanical means, so that it shall not require any 

 attendant. This difficulty, at least, seems to have been obviated by 

 the invention we are about to describe. 



The light is called "Stake's Patent Electric Light," after its in- 

 ventor. It is produced from a galvanic battery of moderate size, em- 

 bracing in its construction and elements several features, which are 

 claimed to be improvements, the object of which is to render the battery 

 constant, continuous, and regular in its action, and economical in its 

 cost. By means of solid copper wires the electric fluid is conveyed 

 to the lamp, which may be placed on a table or suspended from the 

 ceiling. In this lamp are two cylinders of carbon, which are used as 

 electrodes, that is to say, the current of electricity is passed from one 

 to the other as they stand end to end, their ends being separated from 

 one twentieth to one half an inch, according to the power of the cur- 

 rent applied ; and these cylinders are moved by a clock-work arrange- 

 ment, in proportion as they are consumed, at a speed which is regu- 

 lated by the currents. To render the light continuous, it is necessary 

 that these two pieces of carbon should first be brought into actual con- 

 tact, so that the current may pass and then be separated to a short 

 distance. This is accomplished, and here is the grand feature of the 

 invention, by the current itself, without manual aid. As the carbon 

 gradually wears away, at the rate of about an inch in t\vo hours, the 

 same regulated distance between the two electrodes is preserved by 

 like means. The apparatus for effecting this self-regulation is an 

 electro-magnetic instrument, placed directly under the plate of the 

 lamp, through which the current of electricity is caused to pass. The 

 principle of this instrument is very ingenious, in some degree resem- 



