Mr. Brayley, who referred me to those statements, and has extensive knowledge of recorded facts, is unacquainted with any further account relating to them.
The term quantity in electricity is perhaps sufficiently definite as to sense; the term intensity is more difficult to define strictly. I am using the terms in their ordinary and accepted meaning.
Many of the spaces in this table originally left blank may now be filled. Thus with thermo-electricity, Botto made magnets and obtained polar chemical decomposition: Antinori produced the spark; and if it has not been done before, Mr. Watkins has recently heated a wire in Harris's thermo-electrometer. In respect to animal electricity, Matteucci and Linari have obtained the spark from the torpedo, and I have recently procured it from the gymnotus: Dr. Davy has observed the heating power of the current from the torpedo. I have therefore filled up these spaces with crosses, in a different position to the others originally in the table. There remain but five spaces unmarked, two under attraction and repulsion, and three under discharge by hot air; and though these effects have not yet been obtained, it is a necessary conclusion that they must be possible, since the spark corresponding to them has been procured. For when a discharge across cold air can occur, that intensity which is the only essential additional requisite for the other effects must be present.—Dec. 13 1838.
In further illustration of this subject see 855-873 in Series VII.—Dec. 1838.
The great and general value of the galvanometer, as an actual measure of the electricity passing through it, either continuously or interruptedly, must be evident from a consideration of these two conclusions. As constructed by Professor Ritchie with glass threads (see Philosophical Transactions, 1830, p. 218, and Quarterly Journal of Science, New Series, vol. i. p.29.), it apparently seems to leave nothing unsupplied in its own department.
Quarterly Journal of Science, New Series, vol. i. p. 33.
Plymouth Transactions, page 22.
Of course the heightened power of the voltaic battery was necessary to compensate for the bad conductor now interposed.
Bibliothèque Universelle, xxi. p. 48.
In reference to this law see further considerations at 910. 1358. 1705.—Dec. 1838.