VOL. XXVI.] PHILOSOPHICAL TRANSACTIONS. 421 



should immediately run into others of the same degree ; that body will not re- 

 turn into its pristine figure. — Hence appears the nature of that contexture which 

 constitutes soft bodies. 



Theorem 14. — The particles of matter, according to their different structure 

 and composition, will be endued with different attractive forces : for instance, 

 the attraction will not be so strong, when a particle of a given magnitude has 

 several pores, as when it is entirely solid, and without any. 



Theorem 15. — The attractive forces of particles perfectly solid, depend very 

 much on their figure. For should any small particle of matter be formed into 

 a circular lamina of an indefinitely small thickness ; and a corpuscle be placed 

 in a right line passing through the centre, perpendicular to the plane of the 

 circle ; and the distance of the corpuscle be equal to -^ of the semi-diameter of 

 the circle; the force with which the corpuscle is attracted, will be 30 times less, 

 than if the attracting matter coalesced into a sphere, and the power of the 

 whole particle exerted itself from one physical point ; and the same circular 

 lamella more strongly attracts the corpuscle, than another particle of the same 

 weight does, formed into a slender and oblong cylinder. 



Theorem l6. — Salts are bodies whose particles of the last composition are 

 endued with a great attractive force, though there are several pores interspersed 

 between them, that are previous to the particles of water of the last composi- 

 tion ; which being therefore strongly attracted by the saline particles, they vio- 

 lently rush upon them, and disjoin them from their mutual contact, and dissolve 

 the cohesion of the salts. 



Theorem 17. — If two corpuscles mutually tend towards each other, with at- 

 tracting forces decreasing in a triplicate, or more than triplicate ratio of their 

 distances ; the velocity of their mutual impulse will be infinitely greater than at 

 a given distance. Vide Princip. Newtoni, Prop. SQ. 



Theorem 18. — The magnitude of a body heavier than water, may be so far 

 diminished, as at length to remain suspended in it, and not descend by its pro- 

 per gravity. — Hence appears the reason why saline, metalline, and other such 

 like particles, reduced to the smallest parts, remain suspended in their 

 menstrua. 



Theorem IQ. — Greater bodies mutually tend towards each other with less 

 velocity than smaller bodies. — For the force with which the bodies a and b, 

 plate 10, fig. 22, mutually tend towards each other, is principally only in the 

 nearest particles, whilst the forces of the more remote are none at all ; there- 

 fore a greater force is not applied to move the bodies a and b, than the particles 

 c and d ; but the velocity of bodies moved by the same force are reciprocally 

 proportional to the bodies themselves; consequently the velocity with which the 



