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PICTORIAL MISCELLANY. 



ply electricity, or, as you would call it, lightning. As this kind of 

 electricity is induced, or set in motion, by the galvanic battery, which 

 I shall presently explain, and as it varies, in some other respects, 

 from that, which is created by the electrical machine, it has been 

 thought proper to call it galvanic electricity. I suppose most of you 

 have seen the electrical machine, and witnessed some of the curious 

 experiments, which can be tried with it. How quick the sparks fly 

 from it! And then how much mirth is made when "ariii^" of 



o 



boys and girls have taken hold of the chain to receive a shock ! 

 The first time I saw this experiment, I determined to keep hold of 

 the chain at all events. The shock appeared so slight and easy, 

 that I was sure I could retain my grasp ; but, snap ! and my hands 

 were powerless, and I learned, at once, the power of this unseen 

 and mysterious agent. But I am wandering from onr subject. 1 

 will return to it, and explain to you the various parts of the tele- 

 graph ; and first, 



THE BATTERY.- -It was discovered, a great while ago, that when 

 two metals were placed in contact with each other, with some liquid, 

 capable of acting upon one more than upon the other, electricity of 

 a peculiar character would be developed. Look 

 upon the adjoining cut, and you will easily un- 

 derstand what I mean. It represents a glass 

 vessel nearly filled with nitric acid, a zinc 

 plate marked Z, and a copper plate marked C. 

 Now the supposed motion of the electric current, 

 within the glass vessel, is from the zinc plate to 

 the copper one, as the pointers indicate, and if 

 the t\vo metal plates are connected b 



y a wre 



without the vessel, as you will see in the cut, 



the electricity will pass around through the 



wires from the copper to the zinc again, thus 



forming a constant current running round and 



round. The instant the wires are separated, 



however, even in the slightest degree, the circuit is broken, and the 



current stops, for you must bear in mind that galvanic electricity 



will not jump acr-oss a space, in sparks, as it does from an electrical 



machine, but keeps upon the wires or metals. These wires may be 



