82 THE ELEMENTS. 



people believe that all things are composed or made 

 up of these four elements. This is very incorrect, 

 because there are many substances which do not con- 

 tain any of these so-called elements ; and they are, 

 besides, themselves compounded of many different 

 substances. The term elements, in the sense in which 

 it is used by chemists, means a certain set of simple 

 substances, which, by combining or uniting together, 

 form all the various matters that occur in Nature. 



17. To return once more to the example of soap, 

 we may say that the elements of soap are alkali and 

 tallow ; but then the question will arise, what are 

 the elements of tallow and alkali ? which can only 

 be ascertained by chemical experiments. In this way, 

 then, we may analyze, or as it were pull to pieces, 

 different substances, till at last we find that we are 

 unable to separate or decompose them any further, 

 and the substances which then remain are called ele- 

 ments, or simple substances. It is possible that 

 chemists may hereafter discover that some of the 

 substances now called elements are really compounds, 

 and of course it is impossible to prove that they are 

 not so; all therefore that is meant by the term ele- 

 ment, or elementary substance, is that chemists have 

 not yet been able to prove them to be compounds. 



18. There are upwards of sixty of these elements, 

 but it will not be necessary to study the nature and 

 properties of the whole series, because many of them 

 are of very rare occurrence, and found only in small 

 quantities. 



