ABSTRACT
In England, Newton’s telescope, Newcomen’s and Watt’s steam-engines; in Italy the apparatus of Galileo, of Torricelli, of Volta, of the Academy del Cimento; in Holland, the instruments by which Huyghens made his discoveries, and the apparatus of Gravesande and of Otto von Guericke, certainly form precious collections, but how many other important discoveries would not have been likewise represented, if as much care had been bestowed upon preserving the instruments, as in publishing their results. The proofs given by telescopes have allowed of tolerably numerous data being obtained, which measured, at leisure, under the direction of M. Fizeau, by micro-metric means, already permit the reader to state the exactness of the figures which may be deduced from them for the chief results of the phenomenon.
