^0 ERASER ON MAGNETISM. 



nets and electricity on a telegraph line, and how that magnetic 

 involuntary action harmonises with the voluntary or mechanical 

 agency of the operator, exhibiting life or motion in the line, and 

 showing the necessity for the combination of the two powers 

 (similar to those in an animal) for the effectual working of the 

 telegraph. 



The first action is in the solution of acid and water, while 

 preparing them for the battery ; that action is caused by the acid 

 having an excess of mineral and the water an excess of vegeta- 

 able atoms in solution ; when they are placed in contact, each 

 attracts its like material ; and their reciprocal action continues 

 until their particles are equally distributed. Place the ends of 

 a piece of zinc and a piece of copper in this solution, a similar 

 reciprocal action is produced between the metals and the 

 solution. The solution having the excess of vegetable atoms 

 acts upon each piece of metal sejparately. If the upper ends of 

 those pieces of metal are brought into contact, the action is 

 increased at the lower ends, as poles, by the two pieces now 

 forming one magnet, and its poles reciprocating through the 

 solution. There is no action or current exhibited at their 

 junction or middle. Any number of cups of the solution with 

 similar pieces of metal alternately connected to form a battery, 

 will thus be acted upon separately while they are disconnected. 

 If connected or brought into contact through any moist or 

 metallic substance of any length as a telegraph line, the metals 

 will all act together as one magnet ; the force of their union 

 may be noticed in the battery by its increased decomposing 

 action, and in the line by the greater power of its magnets, 

 when the line is in a position to exhibit its polarity, but not 

 otherwise. All the requirements for telegraphing with this line 

 are a <' relay " and " key." The relay is a piece of soft iron in 

 <' horse shoe" form, covered with a small wire coated, the ends 

 of which are connected in the line. The ends of the iron of the 

 relay forming the poles of the magnet, exhibit the force of the 

 line from the battery by attracting another piece of soft iron 

 called an armature. The key is an instrument attached to the 

 line for the purpose of hrealdng the line, by the will of the 

 operator ; when the line is thus broken the force is thrown off 



