Al4 Scientific Intelligence. 
gather upon and in the sphere, being no longer parallel in their course 
nor of equal intensity in every part; or if a sphere of diamagnetic mat- 
ter replace the former sphere, the lines of force will open out where 
the sphere is, being again no longer parallel in direction nor uniform in 
force. When the field of magnetic force is formed between the oppo- 
site flat ends of two large magnetic poles, then these are affected, and 
the globes also, and there are mutual actions ; a paramagnetic body, if ; | 
a little elongated, points axially and tends to go to the iron walls of the | 
field, whilst a similar diamagnetic body points equatorially, and tends to | 
go to the middle of the field. Paramagnetic bodies repel each other, 
and so also do diamagnetic bodies ; but one of each class being taken, 
they attract one another. | 
The convergence of the lines of force upon the opposite sides of the 
paramagnetic sphere, and the corresponding divergence of them on the 
opposite sides of the diamagnetic sphere, the author expresses by the 
term conduction polarity. ‘Chis polarity he carefully distinguishes from 
that which depends upon the reversion of the direction of the power ; 
the latter he considers asa property of the particles of magnetic matter ; 
the former as dependant rather upon the-action of the mass ; the latter 
is an absolute inversion of the direction of the power, the former only 
a divergence or deflection of it. 
Applying the idea of conduction to magnecrystallic bodies, he con- 
eluded that the magnecrystallic axis would coincide with the direction 
of better conduction, and thence concluded, that, if a symmetric crystal 
of bismuth were carefully examined in different directions, it would be 
SUE 
submitted to experiment, than when it was parallel to the magnetic axis. 
By means of the differential torsion balance described in the former 
paper, be was able to make the trial, and found the results were as an- 
ticipated. With calcareous spar and his present balance he was not 
able to establish any difference, but concludes that it will prove most = 
diamagnetic when the optic axis of the crystal and the magnetic axis of 
the field are parallel. 
Advancing to the consideration of atmospheric magnetism, the author 
first refers to the earth as a source of magnetic power from which ema- 
nate lines of magnetic force passing into space according to a particular 
ut recognized distribution, and in obedience to the general laws which 
govern the distribution of power about a given irregular magnet. In 
pure space the magnetic power is considered as transmitted onwards 
with a certain degree of facility which is constant, but may 1” 
creased or diminished by the presence of paramagnetic or diamagnetic © 
continually occur in it under natural circumstances. Four-fi hs nearly — 
by volume of the air is nitrogen, which is a gas that neither underany — 
_ difference of temperature or of expansion shows any alteration In 18 
power of affecting the transference of the magnetic force; whether | 
ed to 2 therefore in one state or another, or when un rg ; 
changes of a corresponding kind by natural a it has no 
