Chapter IV: ELECTRICITY.--Electric Time.--By M. LITTMANN.--An

abstruse research into a natural electric standard of
time.--The results and necessary formulæ. 9793

New Method of Maintaining the Vibration of a
Pendulum.--Ingenious magneto-electric method of maintaining
the swinging of a pendulum. 9794

The Part that Electricity Plays in Crystallization.--C.
Decharme's investigations into this much debated
question.--The results of his work described.--3
illustrations. 9793