36 THE ELECTRIC TELEGRAPH. 



were substituted for the ink reservoirs, striking against bells 

 of glass or metal of different notes. Thus Steinheil's appa- 

 ratus formed also, upon occasion, an acoustic telegraph. 



The history of the subject so far shows us that no single indi- 

 vidual can claim the distinction of having been the " inventor 

 of the electric telegraph ; " but if there is one worker who 

 deserves more credit than another for his energy, intelligence, 

 and success in the service of his adopted science, that man is 

 certainly Professor Steinheil. 



37. The ingenious experiments with which Professor Wheat- 

 stone occupied himself, in 1834, in his researches on the 

 velocity of the electric wave in solid conductors, seem to have 

 first directed his attention to the subject of telegraphy. 

 Mr. Cooke had already employed himself with the construc- 

 tion of telegraph lines for railway purposes before he joined 

 Professor Wheatstone. 



Their first joint invention was a telegraph with five indicators 

 and as many line wires. Its appointments were as follows: 

 Five multipliers of fine insulated copper wire, with light 

 magnet-needles, were arranged in a line across the back of 

 a diamond- shaped dial-plate. The upper side of the plate, 

 which served at the same time as a cover for the case contain- 

 ing the multipliers, was marked with twenty letters of the 

 alphabet, c, j, Q, u, and z being omitted, as capable of being 

 replaced by others, at the expense, perhaps, of a little ortho- 

 graphy, but at the saving of another line wire with its 

 magnet-needle and multiplier. The margin contained the 

 nine numerals and 0. Fig. 18 shows the upper side of the 

 dial-plate, with pointers attached to the axes of the magnet- 

 needles, broken away in the middle, to show the multi- 

 pliers. Each pointer was deflected from its position of rest 

 always under the same angle on each side, so that by observing 

 the deflections of any two needles, and following with the eye 

 the direction pointed out by their nearer ends, at the point of 

 intersection of these imaginary lines would be found the 

 letter intended to be transmitted. Thus, in telegraphing 

 a letter of the alphabet, the deflections of two needles in con- 

 trary directions were always necessary. In Fig. 18, for 



