John Tyndall,
Popular Science Monthly
(1875)
“ If you moisten the hair with oil, the comb will still be excited and exert attraction; but, if you moisten it with water, the excitement ceases; a comb passed through wetted hair has no power over the lath. After its passage through dry or oiled hair, balance the comb itself upon the egg; it is attracted by the lath. You thus prove the attraction to be mutual: the comb attracts the lath, and the lath attracts the comb. Suspend your rubbed glass, rubbed gutta-percha, and rubbed sealing-wax in your wire loop. They are all just as much attracted by the lath as the lath was attracted by them. ”
