52 
IOWA ACADEMY OF SCIENCES. 
The theory assumes that the stabilities of different atoms 
are unlike. Under the action of a strong extraneous 
electric field, or by collision, or by the forces of solution, 
an atom may be sufficiently unstable as to lose one or 
more of its corpuscles. When this happens, it becomes 
electro-positive to the extent of the excess charge on the 
surrounding positively charged sphere. On the other hand, 
other atoms may possess such great stability, or low cor- 
puscular temperature, that under similar conditions they 
are able to take in one or more additional corpuscles thus 
makin*g them electro-negative to the extent of the charges 
of the excess corpuscles taken in. We thus have a division 
of atoms in kind; electro-positive and electro-negative. 
Hydrogen is an example of the first and chlorine of the 
second. 
The valency of an atom is accounted for in a similar 
manner. When an atom is of such a nature that under 
natural conditions, it never loses more than one corpuscle, 
it is univalent and electro-positive; when it can lose two, 
it is divalent; when three, tri valent. On the other hand, 
atoms that can receive an additional atom and only one, 
are univalent and electro-negative. Those that receive 
two are divalent; three, trivalent. It is easy to see that 
the mutability of the atom within the range here indicated 
would be probable inasmuch as the simplest or least com- 
plex atoms, such as hydrogen, carry about one thousand 
corpuscles. It is clear also that the bonds ascribed to 
atoms by the chemist are merely the attractions of the ex~ 
cess charges on the atoms. All chemical affinity is electric 
attraction. 
The Periodic Law of Mendelejefi is accounted for by the 
different arrangements of the corpuscles in the atoms. To 
illustrate this. Professor Thomson employs an experiment 
first made by Professor Mayer. In this experiment a 
number of magnets are made out of a piece of steel knitting 
needle. These magnets are thrust through pieces of cork 
so that they float in perpendicular positions with the posi- 
tive poles up. Such floating magnets, of course, will repel 
each other. If a powerful negative pole of a bar magnet is 
