714 The Outline of Science 



holder, a pad of blotting-paper, a lump of sugar, a little starch, 

 and a hundred other things "as different as different could be"- 

 including even a diamond; and yet the label of the case might 

 correctly state that all this variety included only three elements- 

 Carbon, Hydrogen, and Oxygen. 



Perhaps this is one of the big revelations of chemistry for 

 ordinary people, that in spite of the immense variety of things in 

 the world there is only a relatively small number of things that 

 are really different, namely, the eighty or so chemical elements. 

 We do not know how many words there are in the English 

 language, but there are only about twenty-six generally recog- 

 nised-letters. It is the same in chemistry. Many different hands, 

 but not such a large number of cards ! 



Furthermore, just as there are some letters, like q and z, 

 which are not in very frequent use, in the same way it must be 

 noted that many of the fourscore or so chemical elements are rare, 

 and do not occur in more than a small percentage of the specimens 

 in the museum. Many of the "rare earths," though very im- 

 portant for man's purposes, do not play a large part either in the 

 architecture or in the bustle of the world. They lurk quietly in 

 remote corners take tantalum, for instance. It has been cal- 

 culated that there are, on a very moderate estimate, a quarter of 

 a million of very different kinds of things in this world of ours. 

 But scientific chemistry has shown that this multitude is due to 

 varied groupings of about eighty "really different kinds of stuff," 

 namely, the chemical elements. It is not easy to put the case 

 rightly, for each fresh pattern may be something very definitely 

 new and individual, just as a painter makes many pictures of the 

 same few colours. Every one knows the variety of patterns that 

 result when the pieces of coloured glass in a kaleidoscope are 

 shaken into new combinations, but this is a static diversity. It sug- 

 gests, however, what may result from the shuffling of a few ele- 

 ments, especially when some of these are what is sometimes called 

 "attractive." In general terms, the conclusion, to which common 



