116 Scientific Intelligence. 
from the poles; but Prof. Tyndall exhibited a bar of this substance, 
which set between the flat poles exactly as a magnetic body. Sucha 
bar, however, between the points are equatorial. On raising or lowering 
it, however, it forsook the equatorial position and set axial. In this case 
the local repulsion of the ends between the points caused the bar to set 
equatorial, the influence of length thus predominating over the influence 
structure ; but removed from the sphere of this local action, the di- 
rective tendency of the mass triumphed and caused the bar to set axial. 
The bar in this case was cut with its length at right angles to the planes 
of most eminent cleavage of the bismuth:—it is a proved fact, that 
these planes while the influence of form is annulled, always set at right 
angles to the line piercing the poles, and hence where they are trans 
verse to the length, the bar will set axial. These phenomena were ex- 
amined ina great number of cases; bars were taken from substances 
possessing a directive tendency, and it was so arranged that the directive 
tendency due to structure was always opposed to the influence of length; 
between the points the former tendency succumbed to the later, while 
mens examined by Prof. Tyndall were all diamagnetic ; each of them 
was repelled by the poles of the magnet; cubes of each when suspen- 
ded with the fibre horizontal set between the excited poles, the fibre 
perpendicular to the line which unites the poles. Thinking that wood 
on account of its structure, would exhibit those directive phenomena 
which had been demonstrated in the case of the bodies mentioned at 
the commencement, bars were taken from nearly forty kinds of wood, 
the fibre being at right angles to the length of the bar; in the centre 
of the space, between two flat poles, all those bars set their length from 
pole to pole. But Prof. ‘Tyndall afterwards observed the remarkable 
fact, that homogeneous diamagnetic bodies did the sume. Bars of s¥ 
magnets of hardened steel, as by suddenly bending them, or sir 
‘The Rev. Dr. Scorzssy stated, that, by subjecting to force ordinary 
nets of hardened stee! y St y bendi striking 
