For many years the English public had the privilege of listening to the discourses and speculations of Professor Faraday, at the Royal Institution, on Matter and Forces; and it is not too much to say that no lecturer on Physical Science, since the time of Sir Humphrey Davy, was ever listened to with more delight. The pleasure which all derived from the expositions of Faraday was of a somewhat different kind from that produced by any other philosopher whose lectures we have attended. It was partially derived from his extreme dexterity as an operator: with him we had no chance of apologies for an unsuccessful experiment--no hanging fire in the midst of a series of brilliant demonstrations, producing that depressing tendency akin to the pain felt by an audience at a false note from a vocalist. All was a sparkling stream of eloquence and experimental illustration. We would have defied a chemist loving his science, no matter how often he might himself have repeated an experiment, to feel uninterested when seeing it done by Faraday. The present publication presents one or two points of interest. In the first place, the Lectures were especially intended for young persons, and are therefore as free as possible from technicalities; and in the second place, they are printed as they were spoken, _verbatim et literatim_. A careful and skilful reporter took them down; and the manuscript, as deciphered from his notes, was subsequently most carefully corrected by the Editor as regards any scientific points which were not clear to the short-hand writer; hence all that is different arises solely from the impossibility, alas! of conveying the manner as well as the matter of the Lecturer. May the readers of these Lectures derive one-tenth of the pleasure and instruction from their perusal which they gave to those who had the happiness of hearing them! W. CROOKES. CONTENTS. LECTURE I. PAGE THE FORCE OF GRAVITATION, 13 LECTURE II. GRAVITATION--COHESION, 44 LECTURE III. COHESION--CHEMICAL AFFINITY, 72 LECTURE IV. CHEMICAL AFFINITY--HEAT, 99 LECTURE V. MAGNETISM--ELECTRICITY, 122 LECTURE VI. THE CORRELATION OF THE PHYSICAL FORCES, 147 LIGHT-HOUSE ILLUMINATION--THE ELECTRIC LIGHT, 173 NOTES, 195 Book Catalogue THE VARIOUS FORCES OF NATURE. LECTURE I. THE FORCE OF GRAVITATION.