240 Serentific Intelligence. 
SCIENTIFIC INTELLIGENCE. 
J. Paysics. 
1. Terrestrial Magnetism.—Professor Batrour Srewarr, in 
a letter to Nature, July 1, 1880, eronanee the connection between 
auroras and magnetic storms, Since we have changes produced 
in stationary strata by a moving pani, cannot the reverse be 
true? May we not have discharges produced in moving strata by 
a stationary magnet? The n this case would by ‘convection 
currents produce per in the’ atmospheric strata and the earth 
as a permanent magnet would cause are disturbances, which 
in turn would react pin Hertesthisl magnetism. orking on this 
hypothesis Balfour Stewart has been led to the fact “that certain 
magnetic diurnal changes lag behind cor es ott iy solar changes, 
just as meteorological changes wou nd he also states that 
his observations up to the resent cect to Sabot that an increase 
or decrease of solar activity corresponds to an increase or decrease 
of both magnetic and meteor ological activity. The probability 
of a progress of magnetic phenomena from west to east, corre: 
sponding in character to a progress of eer ilaaion’ phenomena 
is alluded to. Magnetic che groves appears to travel faster, how- 
ever, a meteorological weather. i. 7. 
2. Onthe Reversal of Phetogrmabte Impressions.—M. J. JANSSEN 
eR diseovered that photographic images can be made to pass 
om negative to positive by the wb ett ore action of the same 
lieht which "predies ed them originally. <A a solar photo- 
ese are obtained with an exposure of ou zoey Of a secon 
ese photographs show the granulations of the photosphere, 
the neighborhood of 5, of a seconc f, ever, one 
these lates receives an impression of light during a half a 
second or one second—that is to say, during a time ten to twenty 
disappears in its turn and the developer causes no metallic de- 
posit to be formed upon the image, which appears uniforml 
sk i 
per a Rendus, No. 25, p. 1447, June 21, 1880. 
Elle btro-magnetic Rotation of the Plane of Polaviention “of 
Light in Gases.—H. A. Kunpr and H. W. C. Rénreen continue 
their research upon this subject, using a Gramme machine instead 
