. 
62 Scientific Intelligence. 
‘4 ‘Oe Te Deatalliges in Sout yellow needles, is per- 
manent in the air, and fuses at about 100°. Very soluble in water 
and also in alcohol and ether. —-Liebig’s Annalen, ccii, a bie +d 
1880. 
9. Relation between the Velocity of ogee and the Density of 
Bodies.—Herr H. A. Lorentz refers to the fact that Max- 
well’s theory of light has been examine 4 chiefly in relation to the 
questions of velocity-and of reflection and refraction, and proposes 
rag himself to examine the relation between the index ae refraction 
and the density d of a body, under the supposition that Max- 
well's theory is true. He starts with the hypothesis that an ether 
830% between the molecules of a body, and that in the immediate 
ighborhood of the molecule the state of this ether does not 
er from that which it possesses in a vacuum. He also sup- 
equation K= 
cha as ‘of saatieg ag eat 
eq. (1) in SR stot 
must hold. Under the supposition that all the molecules are not 
equal, one can obtain aera for the index of refraction of a 
mixture. It follows that —~— : TP dd also in this case must be equal’ 
to a constant, and also that ‘aren this value and the analogous 
constants af Monta me 
(n,’+2)d. (n, 
which result om the conditions of the mixture, the relation 
@2)d= oe eer ‘aa,t a7, saa irs s Br 
- hold. “ln this latter equation a,, a,, etc. are the units of 
of the portions in the unit of weight. ’ 'The constant & in n eq. 
a 
