M. Boucheporn, of Paris, made an experiment in mechanics, and deduced from it that the force of gravitation varied according to the greater or less speed of the earth in its orbit. A member of the Academy of Sciences has, to all appearance, completely overthrown such a deduction. " If it were true," he says, "the change in the force of gravitation would amount to one 72d part, and it follows that every timepiece regulated by a pendulum, would be advances or retarded daily at the rate of 72 X 2=144th part of the number of seconds (8G,400) in twenty-four hours, which amounts to ten minutes. Every observatory t clock should therefore be disturbed to this ex-"X tent if such a deduction were true, because S, the earth is retarded and advanced to this ex-S tent in its orbit,"