THE THREE CONDITIONS OF MATTER. 21 



ECTION III. 



THE THREE CONDITIONS OF MATTER. 



53. Conditions of Matter. Matter exists in 

 three conditions or forms the solid, the liquid, 

 and the aeriform. 



54. What is a Solid ? A solid is a bodij whose 

 molecules change their relative positions with 

 difficulty. 



Such bodies have a strong tendency to retain any form 

 that may be given to them. A movement of one part of 

 such a body produces motion in all of its parts. 



55. What is a Liquid?^ liquid is a body 

 whose molecules, easily change their relative po- 

 sitions, yet tend to cling together. 



Such bodies adapt themselves to the form of the vessel 

 containing them, but do not retain that form when the 

 restraining force is removed. They always so adapt them- 

 selves as to have their free surfaces horizontal. Water 

 is the best type of liquids. 



56. Experiment. Sus- 

 pend a glass or metal plate, 

 of about four inches area, 

 from one end of a scale-beam, 

 and accurately balance the 

 same with weights in the oppo- 

 site scale-pan. The support- 

 ing cords may be fastened to 



the plate with wax. Beneath FIG. 5. 



