The Jeans grouping

More precise determination of the distribution of state The Jeans grouping. The knowledge of the distribution of state Za is insufficient to determine the number of collisions for the subsequent time interval At. For that we also have to know how many pairs of molecules are in the process of making collisions of the various kinds at time k.183 We might abbreviate this as the grouping of the molecules. 

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Xa) Almost the whole volume of every Z -star is taken up by the corresponding Jeans grouping and those very close to it. Only a relatively very small part is occupied by groupings appreciably different from the Jeans grouping. 

Xb) The Jeans grouping gives for the subsequent time interval At exactly that system of collision numbers which satisfies the StosszahlansaUs.186... 

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