June 30, 1899.] 



&CIENCB. 



897 



verj' generally admitted by careful students. 

 Lord Kelviu also admits this, bj^ implica- 

 tion, when he says (sec. 31, p. 706) "If the 

 shoaling of the lava ocean up to the surface 

 had taken place everywhere at the same 

 time, the whole surface of the consistent 

 solid would be the dead level of the liquid 

 lava all around, just before its depth became 

 zero. On this supposition there seems no 

 possibility that our present day continents 

 could have risen to their present heights, 

 and that the surface of the solid in its other 

 parts could have sunk down to their pres- 

 ent ocean depths, during the twenty or 

 twenty-five million years which may have 

 passed since the eonsistentior status began or 

 during any time however long." 



In addition to this recognized quantita- 

 tive deficiency, the present writer has been 

 led to question its qualitative adaptability. 

 The phenomena of mountain wrinkling and 

 of plateau formation, as well as the still 

 greater phenomena of continental platforms 

 and abysmal basins, seem to demand a 

 more deeji-seated agency than that which is 

 supplied by superficial loss of heat. This 

 proposition demands a more explicit state- 

 ment than is appropriate to this place, but 

 it must be passed by with this mere allu- 

 sion. It would seem obvious, however, 

 that an earth of heterogeneous constitution, 

 progi'essively reorganizing itself, would 

 give larger possibilities of internal shrink- 

 age, and that this shrinkage must be deep- 

 seated as well as superficial. In these two 

 particulars it holds out the hope of furnish- 

 ing an adequate explanation for the de- 

 formation of the earth where the hypothe- 

 sis of a liquid earth seems thus far to have 

 failed. 



But the essential question here is the 

 possibility of sustained internal tempera- 

 ture. It is urged that the heterogeneous, 

 solid-built earth is superior to the liquid 

 earth in the following particulars: (1) It 

 retains a notable percentage of the original 



potential energy of the dispersed matter, 

 while in the liquid earth this was con- 

 verted into sensible heat and lost in pre- 

 zoic times; (2) it retains the conditions 

 for a slow convection of the interior ma- 

 terial, bringing interior heat to the surface, 

 a function which was exhausted by the 

 liquid earth in the freer convection of its 

 primitive molten state ; (3) it retains larger 

 possibilities of molecular rearrangement of 

 the matter and of the formation of new 

 minerals of superior density, whereas the 

 liquid earth permitted this adjustment in 

 the prezoic stages. In short, in at least 

 these three important particulars, the slow- 

 built meteoric earth delayed the exercise 

 of thermal agencies until the life era and 

 gradually brought them into play when 

 they were serviceable in the prolongation 

 of the life historj^, whereas the liquid earth 

 exhausted these possibilities at a time of 

 excessive conversion of energy into heat and 

 thus squandered its energies when they 

 were not only of no service to the life his- 

 tory of the earth, but delayed its inaugura- 

 tion until their excesses were spent. 



Let it not be supposed for a moment that 

 I claim that the alternative hypothesis of a 

 slow-grown earth is substantiated. It must 

 yet pass the fiery ordeal of radical criticism 

 at all points, but it is the logical sequence 

 of the proposition that a swarm of meteor- 

 ites revolving about the sun in independent 

 individual orbits and having any probable 

 form of dispersion would aggregate slowly 

 rather than precipitately. If the astron- 

 omers and mathematicians can demonstrate 

 that the aggregation must necessarily have 

 been so rapid as to crowd the transformed 

 energy of the impacts into a period much 

 too limited to permit the radiation away of 

 the larger part of the heat concurrently, the 

 hypothesis will have to be set aside, and we 

 shall be compelled to follow the deductions 

 from the white-hot liquid earth, or find 

 other alternatives. 



