Scientific Intelligence. 125 
SCIENTIFIC INTELLIGENCE, 
I. CHEMistry AND Puysics. 
On the — of the vibrations of the ether in the case of polar- 
ined light.—Hat ER has made a communication from Stokes the 
occasion of an Siscamsing examination of the long mooted question 
» whether the vibrations of the ether take place in the plane of polariza- 
tion or at right angles to it. The former opinion it will be remembered 
was held by. Maccullagh and Neuman and at one time by Cauchy ; the 
atter is the view taken by Fresnel, Cauchy, Beer and the majority of 
physicists who have written upon hee subject. Our readers will remem- 
ber that the question considered from the mathematical point of view 
amounts to this. Is the a ee of the ether to be considered ae 
and its elasticity variable; or is the elasticity to be considered co 
stant and the e density variable ? the former supposition leads 1o the con- 
clusion that the vibrations are at right angles to the side of ek so ; 
the latter that they are in this plane. It is only an appeal to experiment 
which can decide the question, or rather it is only this abet which 
can throw the weight of probability upon the one side or the other. 
Haidinger supports Fresnel’s view and bases his reasoning bs og the 
Phenomena of pleochroism in doubly refracting crystals. e shall 
simply translate the author’s succinct expression of his ow bated a2 
I. Let the object be a dichrodus crystal and let equal thicknesses of 
its substance be investigated. 
IL. The follo owing positions are considered as epee 
a. The vibrations of the luminiferous ether are transv 
diffeednt wave lengths 
z 
ordin 
color A, and on € ray or obs ndle of rays, £8 extraordinary a: is eae 
z€d perpendicular to the axis with the color B. 
Inference -—The vibrations are either peblicclag to . plane of 
larization or in this plane. , ante 
Hypothesis. fF 
1, The vibrations are perpendic- ‘he venaes are in the 
to the plane of polarization. 
The direction of the vibrations 
of the ordinary ray lies in its plane. 
For all azimuths there is but one 
such direction of vibration. It is 
in the direction of the axis. 
1. The direction of the v 
tions: of the 
b. To the same colors belong equal wave lengths; to different colors Ps 
