344 CARNEGIE INSTITUTION OF WASHINGTON. 



control and to use it as a basis for the study of the earth's atmosphere, 

 both in respect to its genesis and its maintenance through the geologic 

 ages. In later studies it was found equally indispensable to use this 

 phase of the earth's dynamic envelope as a means of inquiry into the 

 genesis, growth, and maintenance of the earth-body itself. The 

 growth of this basal dynamic concept, and of methods founded on it, 

 does not appear in its real importance in the reports put in print from 

 time to time, and so in this review it is made the thread of the story. 

 In a very similar way, the dynamic encounter of cosmic bodies came to 

 be regarded as a leading factor in the disruption and dispersion of 

 celestial matter precedent to the genetic development of the earth and 

 related bodies, but, as in the previous case, the fundamental and far- 

 reaching functions of dynamic encounter appear only imperfectly in 

 the reports of progress and in the partial publications thus far issued. 

 Not a httle misconception of the range and frequency of dynamic 

 encounter appears in even the limited literature that has been called 

 forth on the subject. For this reason the review sets forth with some 

 emphasis such growth of the concept of dynamic encounter as took 

 place in the earUer studies, preparatory to a more comprehensive 

 discussion in the succeeding parts. 



The second section of the paper treats in general terms of those 

 phases of the dynamic organization of the earth and of the related 

 cosmic units that are brought under consideration, either directly or 

 indirectly, in the studies under this grant. They are more specifically 

 defined and their range of application extended with a view to more 

 convenient use in the concrete cases later considered and in research 

 generally. The subjects treated embrace: (1) the definite recognition 

 of the distinction between the material organization and the dynamic 

 organization of cosmic units; (2) the djmamic envelopes or fields of 

 force of such cosmic units as require consideration in earth-studies; 

 (3) the electric and magnetic spheres of control that are held to sup- 

 plement — in certain cases effectively — the gravitative spheres which 

 alone were considered in the earlier studies; (4) the submerged exten- 

 sion of the dynamic envelopes beyond the spheres of control; (5) the 

 central or nuclear dynamic organizations from which the dynamic 

 envelopes spring; (6) certain pecuHarities in the distribution of force 

 within the envelopes themselves; (7) the interactions of these envelopes 

 in varying forms and degrees constituting the typical forms of dynamic 

 encounter and rendering them readily visualizable. 



The third part consists of a revised treatment of the more essential 

 and especially the more dynamical phases of earth genesis, of earth- 

 growth, of atmospheric maintenance, of basal segmentation, and of 

 other important aspects of the earth's evolution. To find a tenable 

 basis for the interpretation of such fundamental factors of the earth's 

 evolution has all along been the prime object of the whole series of 



