DISCUSSION AS TO ORIGIN 283 



quirements of the mathematical physicists and explained far better, at 

 least, than the heretofore superficial phenomena of vulcanism. 



Professor Arrhenius' conclusions thus cited were that the crust of the 

 earth is solid to a depth of about 40 kilometers where there is a temper- 

 ature of about 1,200 degrees centigrade and the pressure of about 10,840 

 atmospheres — that is to say, at this depth begins a liquid molten con- 

 dition. Beyond that, 300 kilometers, the temperature must, without 

 doubt, exceed the critical temperature of all known substances, and at 

 this point the liquid magma passes gradually to a gaseous magma sub- 

 ject to extremely high pressure. The viscosity and lack of compress- 

 ibility may be greater than those of the liquid magma. These liquids 

 and gases possess a viscosity and incompressibility such as to permit 

 them to be regarded as solid bodies.* This great interior, which is the 

 foundation of Arrhenius' theories, with its celestial temperatures, and . 

 which its author considers as gaseous, is explained as being " something 

 wholly different from what we ordinarily understand as gases.' 1 f 



By experiment and deduction we know that all the rocks of the 

 earth's crust can be melted into liquids and at still higher temperatures 

 converted into gases. It is also known that hot gases can cool into 

 molten liquids, which in turn change into solids on further cooling. It 

 is not illogical to suppose that these processes are repeated, and that 

 from a greater and more primitive gaseous protomagma, as postulated 

 by Arrhenius, all the material of the earth's crust, which is all secondary 

 matter, with its variety of forms and conditions, have been evolved. 



Granting that matter in the earth's interior does exist in a gaseous or 

 potentially gaseous condition, and remembering that these gases are com- 

 posed of all known elements of the earth's substances, the mind can also 

 conceive that on escaping to the cooler surface these gases as they ap- 

 proach the outer crust and atmosphere will be gradually and success- 

 ively converted into all known primary forms of minerals, water, and 

 gases as they exist on the crust today, first condensing into liquids and 

 then into solids, producing exactly the conditions seen in the workings 

 of a volcano, which, as deeply as we can see into it or its roots as ex- 

 posed by erosion, is merely the cooling superficial crustal terminus or 

 conduit of a cooling gas column leading from the greater invisible depths 

 to the surface. 



*" Zur Physik des Vulcanismus." Geol. Foren i Stockholm Forhandl., xxii (1900), pp. 395-419. 



t At this point we may be pardoned for suggesting a new term which will assist in the discus- 

 sion of the interior theory. Tn Arrhenius' statement it will be noticed that he recognizes three 

 zones of condition— the outer crust, the molten inner layers, and the great gaseous centrum. 

 The term " crust " is an accepted one. The liquid mass is the magma. For the matter of the great 

 interior centrum from which the liquid magma and all the known substances and the superfice 

 have theoretically differentiated no name is given. For the want of a better term this grent 

 protoplasm of the inorganic world might be called " protomagma." 



XXXVIII— Bull. Geol. Soc. Am., Vol. 1G. 1904 



