good electric for charging, 106

Theory of the early electricians, 279 of Du Faye, 280 of Dr Watson, 283 of Abbé Nollet, 285 of Mr Wilson, 286 of Franklin, 287 of Æpinus, 294—347 of Mr Cavendish, 348 of two fluids, 349

experiments militating against, 352 of Professor Rusell, 362 of Mr Wilkinson, 363

Thunder, always preceded by lightning, 448 found of, 449 distance of, how measured, 450 explosion of, explained, 451 generally confined to the heavens, 452 storm, progress of, 445

N. B.—In consulting the plates on electricity, the reader is requested to follow the numbers of the figures, and not those of the plates after the first.

END OF THE SEVENTH VOLUME.

DIRECTIONS FOR PLACING THE PLATES OF VOL. VII.

PART I.

Plate CLXVIII. to face Page 162

CLXIX. 180

CLXX. 172

CLXXI.—CLXXIV. 214

CLXXV. 250

Plate CLXXXVI. to face Page 280

CLXXXVII.—CLXXXIII. 324

PART II.

CLXXXIV.—CLXXXVI. 498

CLXXXVII.—CXCIX. 808