ON THE CONSERVATION OF FORCE flS 



Here we have overcome chemical forces by chemical 

 forces, through the instrumentality of the electrical current. 

 But we can attain the same object by mechanical forces, if 

 we produce the electrical current by a magneto-electrical 

 machine, FIG. 102. If we turn the handle, the anker R R 1 , on 

 which is coiled copper-wire, rotates in front of the poles of 

 the horse-shoe magnet, and in these coils electrical cur- 

 rents are produced, which can be led from the points a and b. 

 If the ends of these wires are connected with the apparatus 

 for decomposing water, we obtain hydrogen and oxygen,, 

 though in far smaller quantity than by the aid of the bat- 

 tery which we used before. But this process is interesting, 

 for the mechanical force of the arm which turns the wheel 

 produces the work which is required for separating the com- 

 bined chemical elements. Just as the steam-engine changes 

 chemical into mechanical force the magneto-electrical ma- 

 chine transforms mechanical force into chemical. 



The application of electrical currents opens out a large 

 number of relations between the various natural forces. We 

 have decomposed water into its elements by such currents 

 and should be able to decompose a large number of other 

 chemical compounds. On the other hand, in ordinary gal- 

 vanic batteries electrical currents are produced by chemical 

 forces. 



In all conductors through which electrical currents pass 

 they produce heat; I stretch a thin platinum wire between 

 the ends n and p of the galvanic battery, FIG. 101 ; it becomes 

 ignited and melts. On the other hand, electrical currents 

 are produced by heat in what are called thermo-electric 

 elements. 



Iron which is brought near a spiral of copper wire, tra- 

 versed by an electrical current, becomes magnetic, and then 

 attracts other pieces of iron, or a suitably placed steel mag- 

 net. We thus obtain mechanical actions which meet with 

 extended applications in the electrical telegraph, for instance. 

 FIG. 103, represents a Morse's telegraph in one- third of the 

 natural size. The essential part is a horse-shoe shaped iron 

 core, which stands in the copper spirals b b. Just over the 

 top of this is a small steel magnet c c, which is attracted the 

 moment an electrical current, arriving by the telegraph 



