16 Quarterly German Magazine. 



the frame over a partition, and thus points out the position 

 of the magnetic needle which is in the interior. 



If we unite such a multiplicator with the chain, and then 

 so change the connection, that the current flows in an oppo- 

 site direction, then we observe, that the needle also in both 

 cases takes another direction. If we observe this direction 

 once for all, then the instrument can not only be used as the 

 advertiser of a current, but it shows us, at the same time, 

 its duration, and from the degree of deviation we can judge 

 of the strength of the current. 



In the different experiments which I have described, the 

 closing of the chain was purely metallic. — It only consisted 

 of the multipHcator-wire and the pole-wire, which led to it. 

 Now we will unite the latter with two metallic tin plates and 

 place these parallel to one another in a glass of water. As 

 water is a very bad conductor of electricity, we will add a 

 jittle sulphuric acid to it, through which its power of conduc- 

 tion is immensely improved. The current goes from one plate 

 through the water to the other. We immediately see a quan- 

 tity of little bubbles of gas collect on both plates, which rise 

 to the surface and then are lost. We think we remark, that 

 the number of bubbles on both plates are not the same; on 

 the plate which is connected with the positive pole, there ap- 

 pear fewer than on the other. 



To observe this more exactly, we cover each plate with 

 a funnel filled with water, and catch the developed gas. We 

 obtain in each funnel a colourless gas, but that which is de- 

 veloped on the positive plate, only occupies half the space as 

 the other. We wiU examine the gas of the positive pole more 

 minutely; it has neither smeU, taste, nor colour; if we bring 

 a lighted shaving to it, it takes fixe and burns with a bright 



(138) 



