GEOPHYSICAL RESEARCH DAY. 369 



gold. The history of chemistry is a history of this one problem 

 from the fourth to the sixteenth century — 12 centuries before a 

 man arose whose broader standpoint enabled him to divert the 

 fruitless search into other channels from which a science has slowly 

 arisen which is now so broad as to overlap most of the other sciences 

 and withal so practical that hardly an industry is entirely independent 

 of it. 



The so-called practical questions may therefore as well be left 

 to take care of themselves. There has been no lack of ingenuity 

 in making profitable application of systematic knowledge whenever 

 the need for it became insistent, for the rewards of such effort are 

 considerable. And it is no longer an argument against proceeding 

 to establish relationships in a new field, that the scope of theii* appli- 

 cation can not be completely foreseen. 



Now, what more promising questions occur to one than these: 

 If the earth was originally fluid, as it appears to have been, and 

 has gradually cooled down to its present state, its component minerals 

 must at some time have been much more thoroughly mixed than 

 now; how did they come to separate in the process of cooling into 

 highly individualized masses and groups as we now find them, and 

 what were the steps in their deposition? If the whole earth was 

 hot, whence came the marble of which we have so much and which 

 can withstand no heat? What has given us the valuable deposits 

 of iron, of gold, of precious stones? What determines the various 

 crystal forms found in the different minerals, and what is their 

 relation? Some must have formed under pressure, some without 

 pressure, some with the help of water, and some without. Where 

 is the center, and what the source of energy in our volcanoes ? All 

 these questions and many more the geophysicist may attempt to 

 answer 



