222 POPULAR I.hlCTl'Rl-.S AND ADDRESSES. 



so that \vc max- accept it as one of the truths of 

 science. Well no\v and here, is a point upon 

 which, I think, the practical telegraphist not only 

 can, hut will, before long, give to abstract science 

 data for judging -is the deflection of the needle 

 a direct effect of the auroral current, or are the 

 auroral current and the deflection of the needle 

 common results of another cause ? With reference 

 to this point, I must speak of underground cur- 

 rents. There, again, I have named a household 

 word to every one who has anything to do with 



Deration of working the electric telegraph, 

 and not a very pleasing household word I must 

 say. I am sure most practical telegraphers would 

 rather never hear of earth currents again. Still 

 \ve have got earth currents ; let us make the best 

 of them. They are always with us ; let us see 

 whether we cannot make something out of them 



they have given us so much trouble. 



., if we could have simultaneous observations 



<>f the Underground currents, of the three magnetic 



and of the aurora, we should have a 



vidcnce from which, I believe, without 



