20 
PROFESSOR TYNDALL ON THE DIAMAGNETIC FORCE, ETC. 
Strength of current. 
Attraction. 
70 
08" 
121 
123" 
203 
207" 
271 
268" 
331 
308" 
370 
334" 
In sulphate of iron there is one direction which, in virtue of the molecular struc- 
ture of the substance, sets strongly from pole to pole. The bar No. 1. was so cut 
that this direction was parallel to its length, which therefore set axial ; while No. 2. 
had the same direction across it, thus causing the length of the bar to set equatorial. 
Two comparative series were finally made with two prisms of iron and of bismuth, 
more massive than those previously examined. 
Table IX. 
Bar of iron. No. 2. 
length TO inch, 
width 0‘3 inch, 
depth 0‘3 inch. 
Strength of current. 
Attraction. 
70 
71" 
122 
122" 
167 
168" 
206 
204" 
268 
260" 
322 
311" 
356 
339" 
Table X. 
Bar of bismuth. No. 3. 
length TO inch, 
width 0*3 inch, 
depth 0*3 inch. 
Strength of current. 
Repulsion. 
70 
72" 
126 
T2T 
164 
166" 
206 
205" 
246 
248" 
276 
279" 
364 
344" 
