252 day: geophysical research 



of a body of ore, we must infer them from present appearances 

 and environment. The experimental geophysicist, on the other 

 hand, confronting the same problem, says to himself: Can we 

 not construct a miniature volcano in the laboratory, Can we not 

 build a furnace in which an igneous rock can be formed under 

 such conditions that we can observe its minutest change? He 

 proposes to introduce temperature measuring devices and appara- 

 tus for the determination of pressure, to investigate the character 

 of the surrounding atmosphere and the quantity of water vapor 

 which may be present. He insists upon the chemical purity of 

 every ingredient which goes into the furnace and guards it care- 

 fully against contamination. In these various ways he will 

 undertake to ascertain the exact magnitude of all the causes, both 

 physical and chemical, which have been at work in his miniature 

 rock-producer, together with the physical characteristics of the 

 product. 



A very practical question now arises. Can he do all this suc- 

 cessfully at the temperatures where the minerals form? We must 

 press this question and insist upon a satisfactory answer, for 

 it is by no means obvious that the relations which the physicist 

 and chemist have established at the temperatures of everyday 

 life — energy content, density, solubility, viscosity, dissociation — 

 will continue to hold when substances are carried up to a white 

 heat. The substances, too, are different from those with which 

 the chemist and physicist have been generally familiar. Instead 

 of simple metals, aqueous solutions, and readily soluble active 

 salts, we encounter silicates and refractory oxides, inert in behav- 

 ior and capable of existing together in mixtures of great complexity. 

 We must therefore extend the range of our physics and our chem- 

 istry to a scope in some degree commensurate with the wide range 

 of conditions which the earth in its development has passed thru. 

 Let us follow for a little the actual progress of such an attempt. 



The first step is to provide the necessary temperatures. Obvi- 

 ously, the common fire-clay crucible and the smelter's furnace 

 with its brick lining, will not serve us, here, for all these are them- 

 selves mineral aggregates. The charge, furnace lining, and 

 crucible would go down together in a fall as disastrous as Humpty 



