Nipher — The Laic of Contraction of Gaseous Nebulae. 147 



dM 

 Equating these two values of ^ttt' 



dR^ ^ ~E dR~~ nP \dR) ^~J~ ^"-O.-.-C^) 

 This equation is satisfied by the primitive, 



Since 



\(2 — ny 2'TrkRI (11 )• 



Bj (6) and (11), 



r= 



1 



^ 2 -^ / 4w — 3ji2 



(7 \ (2— n) 27rA;i?2 



(12). 



These three equations satisfy equations (1) (3) and (4). 

 The mass internal to R is 



M= iir I R^SdR. 



{ 



Inserting S from (11) and integrating, 



nr A ( ^ — '' \ / ^ (4n — 3n^)\-^, i-sn 



^ = M4=37i/ [27rk(2-nf) R'"' • (13) 



The weight of a gramme at the surface of this mass is 



3=4f =4rff2-=liiV^^'=^'i'^— • (1*) 

 " IC U — ShM 2Tri-(2 — n)2) pi- ^ ' 



