370 Researches in Magnetic Electricity. 
tric currents from an electro-magnet. The application of the ar- 
mature contributes to the development of magnetism, and on the 
simultaneous withdrawal of the armature, and the galvanic eur- 
rent, the whole amount is suddenly neutralized.* The current 
developed by the application of the armature, I have appreciated 
by the following experiments, and I find its consideration to be 
of very great importance in the application of electro-magnetism 
as a moving power. This subject will be considered at some 
future time, and at present I shall be content with giving briefly 
the reasons why we cannot increase the power with economy, 
where a great number of magnets are charged by the same bat- 
tery. 1. The motion of attracting poles towards each other, ac- 
tually diminishes the power of each magnet, by determining a 
current against the current of the battery. 2. The succession of 
similar or repelling poles, determines a current also against that 
of the battery. 3. The withdrawal of attracting poles (which 
must be effected by mechanical.power, and is of course direetly 
against an independent movement,) maintains the power of the 
magnets, as the new current is then in favor of the battery cur- 
rent. . 
Exp.—To test the value of these secondary currents, I included 
a galvanoscope in the circuit with an electro-magnet, and placed 
the needle beyond the direct influence of the magnet. On bring- 
ing up the armature, the needle returned four degrees, and on 
suddenly applying it, the needle swung nearly back, but imme- 
diately returned to nearly its original deflection of 40°. Sud- 
denly pulling off the armature, the needle swung over 90°. The 
following experiment is still more striking. Connect two electro- 
magnets, so that they shall be charged in sequence, but at the 
same time, and with the same battery. Load one of them with 
about as much as it will hold. Apply the armature to the other 
magnet, and the weight of the first magnet will immediately drop. 
The same may be repeated with either magnet. The power of 
this reacting current, as it may be called, is in proportion to the 
number of magnets in use, charged by the same battery, the num- 
* A steel magnet gains power slowly when its poles are armed and loaded sim- 
ply by determination, or insulation of its poles. Pulling off the armature again 
weakens its power. Jerking it suddenly off, weakens it still further. In this case 
- magnetic forces seem to acquire aeeectee, and go beyond their original sta- 
