Page:Scientific Memoirs, Vol. 1 (1837).djvu/628

Number of Convolutions.	Deviations.				Mean Deviations or $\alpha$.
	1	2	3	4
5	8·6	8·7	8·5	8·6	8·63
10	17·5	17·8	17·2	17·1	17·40
15	26·4	27·2	26·6	25·6	26·45
20	35·5	35·3	35·6	34·6	35·25
25	45·2	46·0	45·0	44·2	45·10
30	54·6	56·5	55·0	54·1	55·05

Hence may be calculated by means of the least squares

$\xi =1\cdot 73\;{\mbox{and}}\;\log .\sin .{\frac {1}{2}}=8\cdot 18478$

therefore we have for the calculated values of $\alpha$

Number of Convolutions.	$\alpha$		Difference.
	Calculated.	Observed.
5	8·77	8·60	+ 0·17
10	17·60	17·40	+ 0·20
15	26·53	16·45	+ 0·08
20	35·58	35·25	+ 0·33
25	45·00	45·10	− 0·10
30	54·67	55·05	− 0·38

Here then the coincidence for this kind of experiments is very great, go that we may regard the position as entirely confirmed, namely that

"the electromotive power which the magnet produces in a spiral, with convolutions of equal magnitude and with a wire of equal thickness and like substance, is directly in the same proportion as the number of the convolutions."

Moreover, we must not let it escape our attention, that in all the three series of observations the differences of the calculated and of the observed deviations are in the beginning positive, and then negative; which seems to show that the electromotive power increases in a somewhat quicker proportion than the number of the convolutions; but the differences are so small, and become, when the observations are made with great care (as the third series proves) smaller and smaller, I therefore ascribe this little irregularity to the influence of some peculiar circumstance which up to the present moment I have not succeeded in discovering.

II. On the Influence of the Distance of the Convolutions of Spirals on the production of the Electromotive Power in them.

In these experiments I employed at first the horseshoe magnet, but