A: Physiological Effects B: Magnetic Deflection. C: Magnets made. D: Spark. E: Heating Power. F: True chemical Action. G: Attraction and Repulsion. H: Discharge by Hot Air. _________________________________________________________ | | | | | | | | | | | | A | B | C | D | E | F | G | H | |_________________________|___|___|___|___|___|___|___|___| | | | | | | | | | | | 1. Voltaic electricity | X | X | X | X | X | X | X | X | |_________________________|___|___|___|___|___|___|___|___| | | | | | | | | | | | 2. Common electricity | X | X | X | X | X | X | X | X | |_________________________|___|___|___|___|___|___|___|___| | | | | | | | | | | | 3. Magneto-Electricity | X | X | X | X | X | X | X | | |_________________________|___|___|___|___|___|___|___|___| | | | | | | | | | | | 4. Thermo-Electricity | X | X | + | + | + | + | | | |_________________________|___|___|___|___|___|___|___|___| | | | | | | | | | | | 5. Animal Electricity | X | X | X | + | + | X | | | |_________________________|___|___|___|___|___|___|___|___| [A] 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._ S 8. _Relation by Measure of common and voltaic Electricity._[A] [A] In further illustration of this subject see 855-873 in Series VII.--_Dec. 1838._