Theory of Magnetism. 251 
the middle of the rod to the point at which the displacement 
through the distance c takes place. 
TABLE VII. 
| 
Tebbaiide @ 9 millim. | @ 6 millim. @ 3 millim. 
_ | SS ea | 
centre ofl! Deflee- | Y% | Deflee- | Y. || Deflee-| ¥ 
© FOC || tion y. ¥, ‘|| tony. Yn tion y Ue 
millim, | | 
90 4268 0032 || 4054 0:057 290 0-112 
100 3960 0-037 || 3558 0052 222) |, OFEG 
110 3640 0:035 | 38160 0°052 168 | 0121 
120 3360 0-035 2800 0059 130 Orit 
130 3100 0-038 2440 0:053 100 0-114 
140 2840 0:032 || 2160 0°056 80 0-097 
150 2640 0-038 || 1900 0-048 60 0°125 
160 2420 0-037 || 1700 0:058 
170 2220 0:028 | 1488 0°052 
180 2080 0-039 1320 0:056 
190 1900 0-033 1160 0-058 
200 1760 0-040 1016 0-060 
210 1605 0-040 884 0-059 
220 1465 0-032 772 0-052 
230 1360 0-035 684 0-051 
240 1260 0:036 608 0-061 
Mean value........- GON. Me feces. (Oy Oats taal ae a toe 0114 | 
Mean value <1) ,4ar 3 , 
Es, of cod $0105 AMA | OTTO Ne sees 0-114 
The above experiments confirm the assumption that there is 
no such thing as free magnetism, but only bound magnetism, 
and that a magnetic force can produce in magnetic bodies 
only so much magnetism as is bound in them and in the sur- 
rounding medium by magnetic distribution in the form of 
closed attraction-curves with equal magnetic moment in each 
section. This mode of regarding the matter is exactly analo- 
gous to the theory of electric molecular distribution; and hence 
the laws which hold good for this may be applied to magnetic 
distribution; and, by the aid of the coefficient 480, which ex- 
presses the ratio of the resistance of air to that of iron, the 
‘influence of the mass and form of iron to be employed in the 
construction of a magnetic field may be determined. 
If an iron bar, upon the middle of which a magnetizing 
force acts, may not be regarded as endless, the formula calcu- 
lated for the endless bar, 
