12 OUTLINES OP NATURAL PHILOSOPHY*. 



a. Let W and W be the weights of two bodies, M 

 and M' their quantities of matter, 

 _W_ M 

 W rr M'* 



The quantity of matter in a body is called its mass. 



28. Small empty spaces are disseminated through 

 all bodies in greater or less abundance, and are 

 called pores. This property of bodies is also called 

 powsity. 



a. In solids, the pores can be seen sometimes by the 

 naked eye, and almost always by the microscope. 



b. In fluids, the dissemination of vacuity through 

 the mass is proved by experiments, though it is not 

 perceived by the eye. MUSCHENBROEK, 91. 

 N3. 



c. The ratio of the quantity of matter to the quanti- 

 ty of empty space contained within the superficies 

 of any body is wholly unknown. 



It is probable, that even in the densest bodies, the 

 quantity of solid matter is very small, compared 

 with the quantity of empty space. NEWTON'S Op- 

 tics. Book ii. Part iii. Prop. 8. 



d. From the porosity of bodies, it follows, that the 

 particles of matter are not on all sides in contact 

 with one another. They may perhaps only touch 

 one another in a few points. 



29. If 



