Such things may be studied for two reasons. We may study them because they are interesting, and we like to see the connections between apparently widely different things without any ulterior motive, or we may study them to ac hieve some practical end. The first is called "pure" science and the second "applied" science. Pure science is, I suppose, closely connected with the small boy's desire to take bis father's watch to pieces. He does not, unless he is unusually optimistic, expect that the watch will go any better after he has taken it to pieces, he simple wants to see how the wheels go round, and to understand how it works.