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Chemistry and Physics. 69 
duces bands, when the spectrum of the spark in air is wigs _ 
ee der Physik mec Chemie, No. 5, 1879, P. 159 
A New Theory of Terrestrial "Magnet ism. 3 Phomalees 
Piliey and AYRTON Nave proposed the following theory of ter- 
restrial magnetism, which is based upon the experiments of Pro- 
fessor Rowland, of Johns Hopkins Guiversity, Baltimore, carried 
out in Professor Helmholtz’s laboratory. In’ these ex periments 
Professor Rowland showed that a magnetic needle is deflected by 
he movement of a static charge of electricity. Professor Row- 
land detailed to the writer of this notice, two years ago, in Cam- 
ridge, the same theory which is now proposed by Professors 
Perry and Ayrton. The theory is that the revolution of the earth 
beneath the électrical charge originally and at all times present in 
the atmosphere may and is sufficient to account for the magnet- 
ism of the earth. 
Professors Perry and Ayrton have eee ae, bre matter to cal- 
culation, and find that the difference of potential between the 
earth and space necessary to produce a di seitacion sufficient to 
four million Daniell cells. They prove, according to this theory 
that “if the earth be electrified, it must, from its very rotation, 
quite independently of all other bodies in the universe, a 
netic; and if it consist of a shell of iron, thick or thin, then that 
the law of distribution of magnetism produced by this electrical 
charge in mechanical rotation, will = identically that given by 
ioohea and physical chemistry. The avid wind fundamental 
ges in chemical philosophy and notation, which have occurred 
during covered b . Fran *’s memoirs, changes 
ig -3 
toward which his own researches have largely contributed, have 
required a thorough revision of the notation of his earlier papers 
The volume opens well therefore oe a reproduction of his “ Con- 
tributions to the Notation of O: and Inorganic Compounds” 
from the Journal of the Chemical nites (1866). The nine chapters 
devoted to pure chemistry contain — of the most important 
For example, the three memoirs on ithe “Isolation of the 
Alcohol Radicals,” the nine memoirs on the “Synthesis of Organo- 
metallic bodies,” the two synthetical researches on acids of the 
