Bibliography. ee 
x Elements of Natural Philosophy ; being an Eepegierntel I 
duction . 4 Study al the Physical Sciences; by Go Biro, A.M, - 
M.D., + F.L.S., &e. &e. With three hundred and seventy-two 
} afaereaig: rom the revised and enlarged niet toe London edition, Load 
ia Ps d. —The dese 
acceptable ce. ve performed. 
in cooing te prose edition. We observe in pee on Pola: 
zation, the following notice of Dr. sir genes s researches on diamagnet- 
ism, which we copy shea benefit of our readers :— oh a 
One of most. interesting contributions to science, fons we . 3 
are indebted to Dr. Faraday, is the discovery of the excitement rene va ’ 
molecular change in certain forms of glass, tate. alcohol, es aa other 
substances when under the influence of the magnetic and electric forces, 
sufficient to cause the rotation of a polarized ray. To show this with 
et a piece»of flint-glass,.a, or much better, a heavy slip of 
fused. borate of lead 2 inches square and 0-5 inch-thick, is placed be- .- 
tween the poles Ns of a powerful electro-magnet, so that the line of ‘ 
force may pass through its hig A. ray of, light BD is hago in 
a vertical plane by reflexion . 
a piece of blackened glass p, and_ 
passing through the 26. ae 
amined at p through a Ni coy 
prism... So long as dere mont Bty ti. Parnas 
e not magnetic, the ray is trans- 
mitted or extinguished as usual du- 
ring the revolution of the prism 
Let this be turned so thatthe ra ray is 
d, and connect the wires c z with the aca the ba spears 
becomes magnetic and the ray becomes visible. It will be n ary to 
the 27 he the right to extinguish the ray which ot ae the 
ence developed magnetism, been made to revo olsk. If the 
i ole be port the observer, the ray will revolve to the right, but if 
this posit reversed, it will, Tprolye!to the left. i 
When a pa tube is filled with water and placed in the axis of a . 
long b elix of wire traversed by a corak from a battery of ten pairs of 
plates, the water assumes | power over a rectiinery 
, turning it to the rif it or the left, reepran tae to the direc- 
ix. 
with water and the helix traversed by t Seameragt im: 
Bg in it, the water: in the centre of : helix will alone exert any 
action on a transm | ray, that. etween the exterior F 
of the coil and th By of the tube ce’ no rotatory power. “piece | 
of borate of ea los placed in the helix ix acquires’ wer 
pai ly glass araday communicated ~ 
temporari to the aa ee 
ate : rope al and oil of tur- 
