ELISHA MITCHELL SCIENTIFIC SOCIETY 27 
heat is a change in the velocity of vibration, and it may is 
serve to explain the variations caused in valence. 
Electricity.—Changes of valence due to electricity are prob- 
ably not unusual but few observations concerning them have 
been recorded. One of the most noteworthy is the produc- 
tion of carbon monoxide from carbon dioxide by the passage 
of the electric spark. 
CO,=CO-+0. 
Chemical Action.—The most usual method of bringing 
about a change of valence is by chemical action. When the 
change is from a higher proportion of the negative element 
to a lower itis commonly called reduction, and the reverse 
change is spoken of as oxzdation. 'These terms are apparent- 
ly relics of an older theory, and are confusing, cspecially to a 
student beginning the study of chemistry. They should be 
limited to cases of the actual removal or addition of oxygen. 
Thus, to speak of the change of ferrous to ferric chloride by 
the action of chlorine as an oxidation is careless and incor- 
Fect. 
FeCl,+Cl=FeCl,. 
It is pushing the type theory rather far to speak of the salts 
of one valence as being derived from the oxide of that val- 
ence and yet this is frequently done. 
When we take ferric chloride and let sulphurous acid act 
upon it, it is called a reduction of the ferric chloride to fer- 
rous chloride, although certainly no oxygen is removed from 
the ferric chloride nor-is oxygen added when the ferrous 
chloride is changed again to ferric chloride by the action of 
nitric acid, and still this is called an oxidation. The use of 
terms for these reactions is evidentiy in need of revision. 
What shall we call the following reaction, cited by Drechsel 
as an ‘‘oxidizing action?” 
2K MnO,+10FeSO,+8H,S0,= 
5Fe,(SO,),+K,SO,+-2MnS0,+8H,0. 
Some hydrogen is oxidized with the formation of water but 
that is not what is meant. The manganese is changed from 
its highest valency to its lowest and the iron from its low- 
