124 TRANSACTIONS OF THE 
tive charge in the atom we may expect a repulsion. In the 
case of a head-on collision the alpha particle is thrown 
straight back on its path. The conclusions of these 
experiments state that the center of an atom is a nucleus 
of positive electrons each positive electron carrying a 
charge equal to the charge on a negative electron. More- 
over the number of positive electrons in this nucleus is 
equal to one-half the atomic weight thus: 
What is there around the positive nucleus? We 
have a speculation on the hydrogen atom which appears 
to satisfy in many respects. N. Bohr, a mathematical 
physicist, has conceived a hydrogen atom as made of one 
negative electron revolving around a single positive elec- 
tron. The attraction between the two charges is bal- 
anced by the centrifugal force on the revolving electron. 
Bohr assumes the negative electron can move ina number 
of different orbits and that it can jump from one orbit to 
another. Under stable conditions when the atom is not 
radiating any energy the negative electron is revolving 
in its innermost orbit. If perchance this electron is 
pulled out of its inner orbit radiation is produced by the 
electron settling back by jumping from one orbit to 
another; revolving, of course, in each orbit before jump- 
ing to the next. It is obvious the energy of the electron 
is different in its different orbits. Bohr assumes radi- 
ation of energy occurs when the electron jumps from any 
orbit to the next inner one. Such a model leaves much 
to be desired. It does not explain the mechanism of radi- 
ation. We know radiant energy is a wave phenomenon 
and a wave is generated by a vibrating body. The Bohr 
atom does not give us any vibrating body. 
In face of these objections the Bohr atom is remark- 
ably successful. A mathematical analysis of its mechan- 
ism shows the relations between the wave lengths which 
such an atom could radiate. It is a significant fact this 
relation theoretically derived does not agree with the 
relation between the wave length of the hydrogen spec- 
trum. When an electric discharge is sent thru hydrogen 
gas we get the characteristic spectrum of that element. 
Also we know there is a state of ionization in the gas at 
this time. That is, we have negative electron knocked 
off the hydrogen atoms. A hydrogen atom which loses. 
