INDUCTION OF MAGNETISM BY ELECTRICAL CURRENTS. 
29.3 
current; and that from the intensity *1060 the rate of increase rapidly declines as 
the limit of magnetization is approached. From the last column of the Table, it will 
be seen that the magnetic effect of the current, separated from the set, increases very 
uniformly with the current, though a little more rapidly. Similar conclusions may 
be drawn from the results of experiments with the electro-magnet of thicker wire 
contained in the next Table, in which all the observations but the last four were made 
at 2 inches distance, and are reduced to the standard of the rest by dividing by 6'668, 
the observed action on the needle at the distance of 2 inches compared with that at 
6 inches. 
Table IV. 
Attraction, at 6 inches, of wire electro-magnet, ^2 inch diameter, 1 yard long, 
wrapped with 27 feet of wire. 
Number of expe- 
Intensity 
Total change of 
Total change 
Set divided 
Total change 
riments forming 
of 
magnetism by re- 
Magnetic set. 
minus 
by square of 
minus set, divided 
the mean result. 
current. 
versal of current. 
magnetic set. 
current. 
by current. 
44 
•0043 
•00213 
•00007 
•00206 
3-786 
•479 
20 
•0089 
•00443 
•00027 
•00416 
3-408 
•469 
20 
•0248 
•01498 
•00180 
•01318 
2-927 
•531 
10 
•0493 
•03835 
•00719 
•03116 
2-958 
•632 
10 
•0900 
•10720 
•03611 
•07109 
4-458 
•790 
10 
•18702 
•08508 
•10194 
6-739 
10 
•19404 
•10560 
•08844 
10 
•1998 
•45360 
•31840 
•13520 
7-976 
•677 
10 
•3448 
•68450 
•43310 
•25140 
3-643 
•729 
^ 6 
1*1633 
1-07320 
•48640 
•58680 
•359 
•504 
1 
2 
3 
4 
5 
6 
7 
My next experiments, recorded in the following Table, were made with a bar of 
hard steel, 7f inches long, ^ of an inch in diameter, wound with 34 feet of silked 
copper wire ^th of an inch in diameter, distributed in two layers. The first five 
observations were obtained at the distance of 3 inches, and are reduced to the stand- 
ard of the remaining observations at 9 inches by dividing by 22*762, the number of 
times that the attraction at 3 inches was observed to surpass that at 9 inches. 
2 Q 
MDCCCLVI. 
