148 : Scientific Intelligence. 
much heated. This heating is attributed to the sudden reversals 
of maximum 
of the magnetic capacity of the iron. In the transmission of 
power by electricity one-half of the useful effect is consumed in 
the development of heat, and in the development of magnetic effect 
where it can not be practically utilized. This loss is a serious draw- 
back to the future of the electrical transmission of power. The fol- 
lowing considerations should be observed in the construction of 
dynamo-electric machines : 
(1.) All disposition of conductors which does not conduce to 
electro-motor effects should be avoided. 
, e conductivity of all wires employed to produce such 
effects should be as great as possible. 
(3.) Metals should be arranged so as to avoid Foucault cur- 
rents. 
.) The magnetism of the electro-magnets should be fully 
utilized in the most direct manner. 
5.) The division of the windings of the inducing wires, through 
which currents of changing direction flow, should be as small as 
possible; the number of divisions should be made as large as pos 
sible to avoid the extra currents which arise with each change of 
current. 
: ween the ether and the particles of the body an effect 
can be produced analogous to those produced by friction, which 
(3.) Each particle is affected by an elastic force peculiar to “g 
i i to 
influenced by the above retarding causes. The mathematical dis- 
cussion, based upon the above hypotheses, leads to results which 
agree, on the whole, very well with Verdet’s observations on the 
change of the plane of polarization of light in bisulpbide of carbon 
and in kreosote. The author considers that the divergence of re- 
sults obtained by Maxwell’s formula from the observed results 1D 
kreosote, proves its untrust worthiness. Lommel’s theory also ex- 
plains the non-ma netic rotation of the plane of polarization.—4””- 
der Physik und Chemie, No. 11, 1881, pp. 623-554. Bee 3 
