Nipher — The Law of Contraction of Gaseous Nebulae. 157 



(19)' 



(20)' 



(21)' 



(22)'. 



Equation (23) also becomes (see (26) ), 



A 



Pv^ = i.ou kjyr . (23)' 



Equations (24) and (25) need not be rewritten. 

 The work done in compressing a mass M, from an infinite 

 volume to a sphere having a radius B is 



00 



Tr=47r \BTdB. 



f 



The value of P being obtained from (19) this integral is 



= 0.636 J^ 

 2B 



If an isothermal distribution of temperature were possible 

 during the compression, n would be unity and the coeflScient 



