132 Contributions to Electricity and Magnetism. 
as not to give the least magnetism to the needle, and so powerful 
at the ending as to magnetize it to saturation, the indication of 
the galvanometer was the same in both cases. 
42. Also, similar results were obtained in comparing the shock 
and the deflection of the galvanometer. In one experiment, for 
example, the shock was so feeble at making contact that it could 
scarcely be perceived in the fingers, but so powerful at the break- 
ing of the circuit as to be felt in the breast ; yet the galvanome- 
ter was deflected about thirty-five degrees to the right, at the be- 
ginning of the current, and only an equal number of degrees to 
the left, at the ending of the same. 
43. In another experiment, the apparatus being the same as 
before, the magnetizing spiral and the galvanometer were both 
at once introduced into the circuit of the helix. A sewing needle 
being placed in the spiral, and the contact with the battery made, 
the needle showed no signs of magnetism, although the galva- 
nometer was deflected thirty degrees. The needle being repla- 
ced, and the battery circuit broken, it was now found strongly 
magnetized, while the galvanometer was moved only about as 
much as before in the opposite direction. 
44. Also, effects similar to those described in the last two pal- 
agraphs were produced when the apparatus was so arranged as to 
cause the induction at the beginning of the battery current to 
predominate. In this case the galvanometer was still equally af- 
fected at making and breaking battery contact, or any difference 
which was observed could be referred to-a variation in the power 
of the battery during the experiment. 
45. Another fact of importance belonging to the same class 
has been mentioned before, (24,) namely, that the action of the 
currents of the third, fourth, and fifth orders produces a very 
small effect on the galvanometer, compared with that of the sec- 
ondary current; and this is not alone on account of the dimin- 
ishing power of the successive inductions, as will be evident 
from the following experiment. By raising the helix from the 
coil, in the arrangement of apparatus for the secondary current, the 
k was so diminished as to be inferior to one produced by the 
arrange ment for a tertiary current, yet, while with the secondary 
current the needle was deflected twenty-five degrees, with the tet- 
Hlary it scarcely moved more than one degree, and with the currents 
of the fourth and fifth orders the deflections were still less, resem- 
bling the effect of a slight impulse given to the end of the needle- 
