"I have been induced by various circumstances to collect in One Volume the Fourteen Series of Experimental Researches in Electricity which have appeared in the Philosophical Transactions during the last seven years: the chief reason has been the desire to supply at a moderate price the whole of these papers with an Index to those who may desire to have them. The readers of the volume will I hope do me the justice to remember that it was not written as a whole but in parts; the earlier portions rarely having any known relation at the time to those which might follow. If I had rewritten the work I perhaps might have considerably varied the form but should not have altered much of the real matter: it would not however then have been considered a faithful reprint or statement of the course and results of the whole investigation which only I desired to supply."