Page:Scientific Memoirs, Vol. 1 (1837).djvu/634

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622
LENZ ON ELECTRO-MAGNETISM.
Angle of deviation. Mean.
1 2 3 4
° ° ° ° °
Copper and
iron spirals
Copper spir. on the 17·3 17·4 17·6 17·7 17·500
armature
Iron spirals 17·3 17·6 17·5 17·9 17·575
17·3 17·4 17·6 18·1 17·600
Copper spirals 17·4 17·4 17·8 18·2 17·700
Copper and
platina spirals
Copper spir. on the 15·2 15·4 15·8 15·8 15·500
armature
Platina spirals 15·7 15·4 15·9 15·4 15·600
15·7 15·4 15·8 15·4 15·575
Copper spirals 15·4 15·8 15·3 15·9 15·600
Copper and
brass spirals.
Brass spir. on the 18·4 18·3 18·4 18·2 18·350
armature
Copper spirals 18·5 18·2 18·1 18·3 18·275
18·4 18·2 18·5 18·4 18·375
Brass spirals 18·4 18·3 18·3 18·3 18·325

If we now combine the single means together and convert the decimals of the degrees into minutes, we obtain from this table the following results:

Copper spirals, deviation
Iron spirals, ———
Copper spirals, deviation
Platina spirals, ———
Copper spirals, deviation
Brass spirals, ———

Since in this case the resistances remain the same for every pair of observations, our chief equation (A.) gives, when treated as before, the following proportions of the electromotive powers, if we designate them for copper, iron, platina, and brass with :

These three proportions are all of them so near to unity that there will exist no doubt as to the fact, that wires of copper, iron, platina, and brass suffer one and the same electromotive action; and that I may be allowed to extend the same position by analogy, even to all other metals and substances in general, until direct experiments shall have left the matter beyond all doubt. We shall have therefore the law,

"that the electromotive power which the magnet produces in spirals