24 Quarterly German Magazine. 



sure. Such magnets are called electro-magnets. They can, 

 if the current be strong enough, attain to very great power, 

 so that we can hang some hundred weight of iron on them, 

 which they can carry, but it falls away from it, as soon as 

 the current is interrupted. By this means, it is possible to 

 produce electrical motions in a distant place. For instance, 

 if we place a chain in Berhn and conduct the wires as far 

 as Cologne to an electro-magnet, the magnet in Cologne ^^'iU 

 attain its magnetism and lose it again, as soon as we open 

 and shut the chain in Berlin. A piece of iron brought in 

 Cologne near the electro-magnet, a so-caUed anchor.^ w^hich 

 is kept in equilibrium by a spring, wiU be attracted to it as 

 soon as the current is closed in Berlin, and is again detached 

 if the current be opened. We can use these motions to give 

 signs. 



We can also set machines in motion with the help of 

 electro-magnetism. If, for example, we bind a hook to the 

 anchor (as it is fixed to the pendulum of clocks which are 

 placed against the wall), which interlocking in the spokes of 

 a wheel, set it turning, we can set the hand of a clock in re- 

 gular rotation, if the closing and opening takes place regularly. 

 This last can be efiected by the pendulum of a clock, but 

 then the electro-magnetically moved hand must keep con- 

 tinually the same pace as the closing and opening of the 

 clock. As, how^ever, we can insert many such electro-magnets 

 with clock work in the same conduction, we can also, by 

 means of one clock, keep many others, in the most different 

 places, in the strictest unity with one another. 



It has also been tried to employ electro-magnetism to 

 raise burdens, but the machines which are necessary for the 

 purpose, are much too expensive to be brought into practice. 



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