A LITTLE CHEMISTRY 33 



is made up of molecules, each of which, contains 

 precisely twelve atoms four of carbon, six of 

 hydrogen and two of oxygen. 



Hence chemical symbols. Each kind of matter 

 is represented by some letter or letters of the al- 

 phabet, C represents carbon, H hydrogen, N 

 nitrogen, O oxygen, and so on. If the molecule 

 contains more than one atom of the same kind, 

 the number is indicated by a little numeral at the 

 right and bottom of the letter. Thus, H 2 O is 

 water; CO2 carbon dioxide; C 4 H 6 O 2 alcohol. 



Every form of matter in the universe takes its 

 peculiar character from the molecules of which 

 it is composed, and the molecules take their pecul- 

 iar character from the atoms composing them. 



The number of atoms in the molecule varies 

 from two or three to over one thousand. The 

 molecule of water has three atoms; the molecule 

 of protoplasm has over one thousand. 



The size of the molecule is almost infinitely 

 small not more than the one fifty-millionth of 

 an inch in diameter. That is to say, fifty millions 

 of these minute bits of matter, placed side by side, 

 would form a line not more than an inch in length. 



The atoms which compose these small bodies are, 

 of course, much smaller at least twice as small. 

 To form a line one inch in length would require, 

 at least, one hundred million atoms. 



But small as these bodies are, the electrons are 

 thousands of times smaller. It is estimated that 

 the mass of matter contained in one electron is a 



