3 oo 



Common Science 



Phosphorus (P) 



Platinum 

 Radium 

 Silver 

 Sodium 



Sulfur 



Tin 



Zinc 



(Pt) 

 (Ra) 

 (Ag) 

 (Na) 



(S) 



(Sn) 



(Zn) 



Phosphorus makes matches glow in the dark, 

 and it makes them strike easily. 



You are not acquainted with sodium by it- 

 self, but when it is combined with the poison 

 gas, chlorine, it makes ordinary table salt. 



For the rest of the elements you can refer to any text- 

 book on chemistry. 



How elements hide in compounds. One strange 

 thing about an element is that it can hide so completely, 

 by combining with another element, that you would 

 never know it was present unless you took the combi- 

 nation apart. Take the black element carbon, for in- 

 stance. Sugar is made entirely of carbon and water. 

 You can tell this by making sugar very hot. When it 

 is hot enough, it turns black ; the water part is driven 

 off and the carbon is left behind. Yet to look at dry, 

 white sugar, or to taste its sweetness, one would never 

 suspect that it was made of pure black, tasteless carbon 

 and colorless, tasteless water. Mixing carbon and 

 water would never give you sugar. But combining 

 them in the right proportions into a chemical compound 

 does produce sugar. 



Not only is carbon concealed in sugar, but it is present 

 in all plant and animal matter. That is why burning 

 almost any kind of food makes it black. You drive 

 off most of the other elements and separate the food into 

 its parts by getting it too hot; the water evaporates 



