An essay on the powers and mechanism of nature; : intended, by a deeper analysis of physical principles, to extend, improve, and more firmly establish, the grand superstructure of the Newtonian system. / By Robert Young.

Young, Robert

Date:: M DCC LXXXVIII. [1788]

Credit: An essay on the powers and mechanism of nature; : intended, by a deeper analysis of physical principles, to extend, improve, and more firmly establish, the grand superstructure of the Newtonian system. / By Robert Young. Source: Wellcome Collection.

146/374 (page 118)

$[ 1*8 ] a's depending 'on die privutibn of the iiiipulfe, or it m^y be confidered as depending on the tipuiUhtium { of the conftituem aQions (f 114), as if'no impnlfe had been'given to it. Again, if a contrary and equal impulfe be given from another hand, the body will alfo become inac- ' tive, as if no impulfe were given to it, by the equilibrium of the two impulfes, j When 'an accessory activity in a body CEASES, EITHER THE BODY IS DEPRIVED OF ITS ACCESSORY ACTIVE SUBSTANCE, OR HAS RE- CEIVED A NEW AND EQUAL QUANTITY OF ACCESSORY ACTIVE SUBSTANCE, MOVING IN A CONTRAR“Y DIRECTION. The body lofes its accessory activity ' either by the privation or the equilibrium of the ACCESSORY active SUBSTANCE (u 117); for finCC the quality of a&ivity has ceafed, either by the fecond rule, the-fubftance poflefling that quality has quitted the body, or by the fifth, the quality has been deftroyed by the union of its con- trary. In order the better to underftand the feveral T ^ vrays in which matter may be ^faid ‘to be adive inaflive, the following corifiderations may be ilfeffiil. A^ivity$