﻿a 
  Spherical 
  Gaseous 
  Nebula. 
  

   Fig. 
  4. 
  

  

  T 
  E 
  3 
  is 
  the 
  curve 
  of 
  temperature, 
  and 
  D 
  3 
  E 
  3 
  is 
  the 
  curve 
  of 
  density, 
  for 
  a 
  

   gas 
  for 
  which 
  fc=l§. 
  T 
  E 
  4 
  and 
  D 
  4 
  R 
  4 
  are 
  corresponding 
  curves 
  for 
  

   a 
  gas 
  for 
  which 
  &=lf. 
  

  

  