56 



A YEAR IN SCIENCE 



may be decomposed into other simpler forms of matter 

 and thus be proved to be a compound. Water and 

 other familiar compounds were at one time thought 

 to be elements. 



An element may be defined as a substance Avhich can 

 not be separated into simpler substances by any known 

 means. 



Number of elements. The number of substances now 

 supposed to be elements is not large. There are eighty- 

 four elements. Probably there are some undiscovered, 

 but it is generally believed that the present number 

 will not be greatly increased. These elements are 

 analogous to the letters of the alphabet, and by their 

 various combinations make up the matter of the uni- 

 verse, somewhat as letters form words. 



About ten of these elements are gases at ordinary 

 temperatures, two are liquids, and all the others are 

 solids. 



Each element is designated by a symbol, which is an 

 abbreviation of the name, or in some cases an abbrevia- 

 tion of the Latin name. A list of the more common 

 elements with their svmbols follows : 



Aluminum 



Antimony 



Argon 



Arsenic 



Bismuth 



Bromine 



Calcium 



Carbon 



Al Chlorine 



Sb Copper 



A Fluorine 



As Gold 



Bi Helium 



Br Hydrogen 



Ca Iodine 



C Iron 



Cl Krypton Kr 



Cu Lead Pb 



F Magnesium Mg 



Au Manganese Mn 



He Mercury Hg 



H Neon Ne 



I Nickel Ni 



Fe Nitrogen N 



