^{page 25 note *} The publication of this paper was delayed partly under the idea of prosecuting the experiments of which it contains an account; but the author having engaged in some other researches, which appear to him of more immediate importance, he merely prints this communication in its original form.—April 1834.

^{page 26 note *} P. 478.

^{page 26 note †} Edinburgh Journal of Science, i. 211.

^{page 28 note *} It is surprising that Coulomb's instrument has not been more employed in this inquiry. Becquerel seems only to have used it once, and Dr Brewster had recourse to the laborious and unsatisfactory method of causing pyro-electric crystals to lift fragments of the Arundo Phragmites, which can give no comparative results.

^{page 31 note *} Ann. de Chimie.

^{page 31 note †} P. 477.

^{page 32 note *} The best pair of series gave,

^{page 33 note *}

^{page 35 note *} It is No. 3. of the Series, at the foot of p. 32.

^{page 37 note *} The disk during this time was of course slowly parting with its charge.