1 68 The American Geologist. September, i9oa 
supply the parts which render the whole a useful machine. 
This he would he ahle to do just in proportion as he had 
mechanical insight. 
So the geologist tits together his numerous diverse facts. 
If he finds a solution of his prohlem which gives accordance 
to all the numerous facts observed, he may be sure he is on the 
right track even if he is incapable of seeing the full truth, for so 
delicate is the adjustment of facts that where they are numer- 
ous there is usually only one way to put them together. Just 
in proportion as the man has a working knowledge of the prin- 
ciples of physics and chemistry and biology and the other cog- 
nate sciences will he be able to eliminate erroneous explanations, 
combine the facts into groups under true theories, and correct- 
ly infer how the dififerent g^roups are to be adjusted, how the 
various facts which seem at first to have no definite relations 
are related. Or, to put it in another way, in proportion as he 
knows the rules of the game will he be able correctly to inter- 
pret the meaning of phenomena and from them to project into 
the unknown. The importance of understanding the rules 
of the game is not often appreciated. To the person who is 
ignorant of the principles of the various sciences all things are 
possible. So many wonderful things have happened within the 
past half century that he thinks it possible for anything to hap- 
pen. He has no principles by which he can determine whether 
or not a statement is probably true. Hence all sorts of grotesque 
notions iiourish. Indeed the very fact that so many wonderful 
things have been accomplished makes many more ready to 
reg"ard as possible almost anv alisurdity announced by some 
so-called "professor.' 
Perhaps at no time in the history of the world has the public 
shown more ready credulity than at present. Indeed, it sesms as 
if the more grotesque and preposterous an idea the more likely 
it is to receive attention. And this credulity is not confined to 
those who are altogether ignorant of science. A man may be a 
very narrow expert in orie direction of science and be wholly ig- 
norant of the rules of the game in reference to another science. 
For instance, when an eminent liiologist says 'bell-ringing, the 
playing on musical instruments, stone-throwing and various 
movements of solid bodies, all without human contact or any 
discoverable physical cause — still occur among us as they have 
