2 ELEMENTARY GENERAL SCIENCE CHAP. 



understand what meaning the word conveys, and this can be best 

 accomplished by one or two examples. We say a strawberry is 

 sweet, or a strawberry has the property of sweetness ; the paper 

 of the book is white, or the paper possesses the property of 

 whiteness ; the sun is bright, or the sun is noted for the pro- 

 perty of brightness. Evidently, then, "properties are certain 

 effects caused by the things ivhich are said to possess them." 



Properties possessed by all kinds of Matter. There are 

 certain properties possessed in common by all kinds of matter ; 

 these are said to be general properties. 



1. Matter must occupy a certain space, or possesses extension; 

 the larger it is the larger the space occupied by it. 



2. It will further be obvious to every one that two material 

 things cannot occupy the same space at the same time. This pro- 

 perty is expressed by saying that matter is impenetrable. To be 

 quite accurate, we have to know something about the way in 

 which matter is built up. We shall see more fully later that it 

 is generally supposed that every kind of matter is built up of 

 small constituent parts, which are incapable of division, and 

 that it is really only these indivisible parts which are im- 

 penetrable. 



3. Matter offers resistance. We become aware of this, in the 

 case of solids, if we knock ourselves against the wall or the 

 table ; if we swim or wade in water we know the same thing is 

 true of water, and so we find it to be of all liquids ; if we 

 attempt to run with a screen in front of us we become conscious 

 of the resistance offered by the air to our onward progress, and 

 from this argue that gases, too, offer resistance. 



4. Matter has weight. Without knowing the full significance 

 of the expression weight, we shall have a sufficiently clear idea 

 of what is meant by this property from its familiar use in every- 

 day conversation. By lifting a solid we become conscious of its 

 possession of this property ; if we lift an empty bottle and then 

 when it is full of any liquid, we shall find it is lighter in the first 

 instance, or, as we say, the liquid has weight. By the exercise 

 of sufficient care, in just the same manner it can be shown that 

 gases have weight. 



5. Matter transfers motion to other things when it strikes against 

 them. If we throw a stick at a cocoa-nut at a fair, or send a jet 

 of water at a ball, or blow at a piece of paper, another of the 

 general properties of matter can be demonstrated, namely, the 

 power of giving motion to other things by striking against them. 



