On the Electric Telegraph of Prof. Morse. 65 
independent wires ; experience has proved that the inability lay 
solely in the imperfection of structures. 'T'wo copper wires have 
worked independently and well through 300 miles. The wire 
is expected to work equally well through twice the distance. No 
mutual influence is exerted by the two currents. Some careful 
experiments, made with a view to ascertain whether a secondary 
cutrent might not be induced in one wire from the primary cur- 
rent in the other,-proved conclusively that no appreciable effects 
could be traced on either from any arrangement of the other 
with relation to battery or ground. 
» ain, snow, &c. act as disturbing influences with less power 
than would be supposed, but in proportion to the excellence of 
insulation ; since at times during severe storms, lines have worked 
vell through their entire extent, and at others a light shower cuts 
off even the nearest station. 
_ Aside from the enumerated difficulties, there is one which will 
passing out by a very fine wire,) the ring is connected with 
the ground. The other device consists of an arrangement, m 
construction, resembling the receiving magnet, (fig. 2.) The 
main wire, before coming to the instruments, connects with and 
includes the helices of this magnet, (whose wire is quite coarse, ) 
and it connects also with the upright lever. The right-hand stand- 
ard connects with the ground. The atmospherical current pow- 
erfully charges the magnet, the armature is attracted and the lever 
brings the points (a a) in contact—thus a ground connection 1s 
mstantly formed and the current passes out. In this case, both 
sions and atmospherical currents are “ turned out of doors.” 
though these devices may prevent the destruction of receiving 
magnets. neither can secure regularity to the working of the in- 
Struments, since currents will take each and every ground con- 
ductor, and enough passes through the receiving instrument to 
_ Sxcoxp Serres, Vol. V, No. 13.—Jun., 1848. a 
