446 Miscellaneous Intelligence. 
less extent when the galvanometer is applied on a sufficient length of 
wire, and between two earth connections; but that wires having | no 
earth connection, or only one, exhibited no currents. 
I also found by simultaneous observations on two alvanometets, ap-_ 
plied one at each extremity of a wire forty-one miles long, that the 
But the most interesting fact which appeared during.these observations, 
and that which bears immediately on the remarks contained in the let- 
ter of M. de la Rive, is that there is a daily movement of the galvanom- 
eter needle, similar to that of the horizontal magnetic needle, produced _ 
and vary from 7 to 10 o’clock both in the morning and evening ; 
the greatest regularity is observable in the morning, and the mean rev 
t to disturbances of greater r less force and duration, which a 
found to be of greatest energy during magnetic storms, and 
ssages. 
xt experiments were madé with a view to ascertain the a 
tion in nee these- ee srr ; and the result, as determ 
from numerous gbservations, ‘denotes it to be from northeast to 
west. The nearer this eneaa appfoached, the more decided is t 
fect on the galvanometer ; but between east and south, and b 
of the morning (at which time the currents trave — 
Seriation is easterly ; also, that the large disturbances called n 
storms are simultaneous on both instruments. 
But although there is this resemblance in the general features 0! 
movements of both needles, the wees described are not similar. + 
movements of the galvanometer needle are more frequent and rapi¢ 
than the declinometer, and the deflection frequently chides over from 
right to left without a corresponding movement of the declinometer. 
on reading M. de la Rive’s letter, because it rather curiously happens, 
that the unusual delay which has arisen in the publication of my p® 
