DIASTROPHISM AND THE FORMATIVE PROCESSES 131 



supported some years later by the studies of Clerk-Maxwell, '^ and 

 their common results were afterward verified by the spectroscopic 

 observations of Keeler, who demonstrated that the rings are formed 

 not of gas, as once supposed, but of discrete particles revolving in 

 independent orbits, in other words are minute satellites or satel- 

 Ktesimals. From a recent study of the albedo of the rings. Bell 

 has concluded that the largest masses in them probably do not 

 exceed three meters in diameter — at least they are not more than 

 a few meters across — while the majority of the visible particles are 

 very much smaller, ranging down to the dimensions of wave- 

 lengths of light.^ 



For the immediate purposes of our study, the important point 

 is not so much that bodies entering this zone of disruption either 

 from without or within are reduced to relatively small particles, 

 though this is important, as that these conditions of stress from the 

 controlling body stand in the way of the organization of any new 

 body within this zone. " So far as the aggregation of independent 

 bodies of any notable mass is concerned, this is an inhibitive zone. 

 Considered with reference to the controlling body, it may perhaps 

 be said to be a protective zone, tending to preserve its isolation, 

 independence, and undivided sovereignty. 



In view of uncertainties as to the precise qualifications the 

 Roche limit might require in the case of a rotating nebular spheroid, 

 Moulton worked out a limit of similar nature but on a different 

 basis, the purpose of which was merely to fix a more certain limit 

 within which the organization of nebulous matter would be in- 

 hibited.^ This limit was placed at 1.38 times the radius of the 

 nebular spheroid, or a little more than half the radial extent of the 

 Roche limit. 



V. Accepting as a working basis the Newtonian doctrine of the 

 unlimited penetration of the force of gravitation, it is a logical 

 deduction that all space is under the immediate domination of 



^"On the Stability of Motion of Saturn's Rings," Scientific Papers of James 

 Clerk-Maxwell, Vol. I, pp. 288-375. 



^ Louis Bell, "The Physical Interpretation of Albedo, II. Saturn's Rings," 

 Astro physical Journal, L (July, 1919), pp. 1-22. 



3 F. R. Moulton, "An Attempt to Test the Nebular Hypothesis by an Appeal to 

 the Laws of Dynamics," Astrophys. Jour., XI (1900), pp. 122-26. 



