THE ELECTRIC PEN. 



249- 



magnet, before which it turns with great rapidity, the current being inter- 

 rupted twice in every revolution by the commutator. The current which 

 moves this little apparatus is furnished by a pile of two elements in bichro- 

 mate of potash, according to Mr. Edison's arrangement, which is considered 

 very successful. Carbon and zinc are employed, and when ready for action 

 the battery assumes the appearance of the cells in the illustration. When 

 the operator wishes to discontinue writing, he simply raises the stem which 

 has the electrodes attached to it, and the elements are thus preserved for a 

 future time. 



Under these circumstances the battery could be made to last several 

 days without any renewal of the liquid, and the plates will last for weeks. 

 Thus a very simple arrangement is at our disposal. Let us see what use 

 can be made of it. 



Fig. 259. Edison's Electric Pen 



When we use the electric pen we obtain a great number of small holes 

 close to each other. Such hand-writing is not easy to decipher by mere 

 inspection like ordinary writing. By holding it up to the light it is more 

 easy to read, but in both instances reading is not easy, nor does it come by 

 nature as Dogberry declares. But if we consider the paper as a " negative," 

 we may obtain a number of positive proofs or copies of the writing. To 

 obtain these successfully we must use a press, as shown in the accompanying 

 illustration (fig. 260). 



The writing, or negative, is placed upon the cover to the left, where it is 

 firmly fastened. Upon the body of the press a sheet of white paper is placed, 

 and when the lid is shut down the negative comes in contact with the paper. 

 By means of a roller, represented in the box, the writing is blackened, the 

 ink penetrates into all the holes which are upon the paper, and after the 

 manner of a stencil plate the impression will be found upon the paper when 



