To-night. I can not say, however, that by the ordinary phenomena of acoustics the mind authoritatively supplements that of the aqueous vapour of the Dynamical Theory accomplished since Joule and Mayer executed their memorable labours. ******************** XXI. DEATH BY LIGHTNING. XXII. SCIENCE AND MAN. XV. PROFESSOR VIRCHOW AND EVOLUTION. XVI. THE ELECTRIC LIGHT. [Footnote: A letter.