Nipher — Primitive Conditions in the Solar Nebula. 119 



An inspection of this equation shows that for any fixed 

 value of Tj there will be a definite value of H^ which will 

 make the radius R of the isothermal T a maximum. 



The condition for this maximum is 



The condition thus determined is 



L 4 — 37Z J 0.9975(4 — 37i)7i2aT ^ ^ 



According to this equation, the higher the temperature of 

 the isothermal the smaller must be the radius of a contracting 

 nebula when the radius of the isothermal has reached its 

 maximum. This shows that the outer isothermals are con- 

 tracting, while the inner ones are enlarging. The maximum 

 radius It of any isothermal is found by substituting the value 

 i?Q of (59) in (58). The maximum R is 



I 4 — 3n J 



(2— n)^ kM^ 



0.9975(4—3/1)71 2CT 

 E = L J __ (60) 



[^^ 4 — 3?i J 



In like manner this value B^ in (57) gives for the value of 

 X when B for any isothermal is a maximum 



2-n 



(-\=x ^[4 — 3h"|2» 



[^o/R-rnl I 2—71 J ' ^ ^ 



In the former paper it was shown that for oxygen, hydro- 

 gen, nitrogen, and air, 7i= 1.101. Hence 



ic = 0.901. 



