HOUSES TELEGRAPH. 



the case of the French railway telegraphs, and in that of the 

 telegraph explained in (201). 



Let us then suppose that by putting down any key, that 

 inscribed with A for example at the station s, a certain dial or 

 wheel at s', having upon it letters corresponding with those of the 

 key-board at s, is so moved that the letter A is brought into a 

 certain position. The letters upon this wheel are formed in relief 

 like type, and when successively brought into the necessary 

 position by the action of the current, having previously passed in 

 contact with an inking apparatus, a band or ribbon of paper is 

 pressed against them by means provided at the station s', and the 

 impression of the letter is made upon the paper. By the next 

 action of the current, the succeeding letter transmitted is brought 

 to the same position, the ribbon of paper being meanwhile drawn 

 forward, another impression takes place, and so on. 



The apparatus by which the ribbon of paper is moved, the type 

 inked, and the paper pressed against it is not worked by the 

 current. That process is effected by mechanism put in operation 

 by the agent at the station at which the dispatch is received. 



In the figure, the ribbon of paper is represented at F, upon a 

 roller from which it is gradually drawn, as letter by letter the 

 words of the dispatch are impressed upon it. The black band 

 which appears upon another roller is an endless strap by which 

 the types are inked. 



In the mechanism as well of the transmitting as of the 

 receiving apparatus, there are many details showing much 

 ingenuity of contrivance, and resources of invention, which, 

 however, are too complicated to admit of any clear exposition 

 without numerous plans and sections, and which we must 

 pass over. 



The printing apparatus, at the station at which the dispatch is 

 received, is put in operation by the action upon the treddle, 

 in the same manner as in the transmitting apparatus at the other 

 station. 



The galvanic apparatus, which supplies the current for working 

 this apparatus, is the battery of Grove, described in (34). About 

 thirty cylindrical pairs are necessary for a distance of 100 

 miles. 



The first line operating with this apparatus was established 

 between New York and Philadelphia in 1849. 



