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

		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	$\alpha \;\,=17^{\circ }\;36'.0$
Iron spirals,	———	$\alpha '=17\;\;35.2$
Copper spirals,	deviation	$\alpha \;\,=15^{\circ }\;34'.5$
Platina spirals,	———	$\alpha '=15\;\;35.2$
Copper spirals,	deviation	$\alpha \;\,=18^{\circ }\;19'.2$
Brass spirals,	———	$\alpha '=18\;20\cdot 2$

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 $x,\,x',\,x'',\,x'''$:

${\frac {x}{x'}}={\frac {\sin .(8^{\circ }\;43'.0)}{\sin .(8^{\circ }\;42'.6)}}=1.00033,$

${\frac {x}{x''}}={\frac {\sin .(7^{\circ }\;47'.2)}{\sin .(7^{\circ }\;47'.6)}}=0.99912,$

${\frac {x}{x'''}}={\frac {\sin .(9^{\circ }\;\;9'.6)}{\sin .(9^{\circ }\;10'.2)}}=0.99894.$

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