PRIMITIVE CONDITIONS IN THE SOLAR NEBULA.* 



Francis E. Nipher. 



In a recent number of these Transactions,! the author hft&'-' 

 deduced the general equations for the contraction of a gasD^ 

 ous nebula. The nebula was considered as a heat engine. 

 The piston face is any spherical surface, concentric with the 

 gravitating center. The load on the piston is the weight of 

 layers of the gas superposed upon the piston face. As con- 

 traction proceeds, this load increases in a perfectly definite 

 way, due to the increasing weight of superposed layers, as 

 their distance from the center decreases. It was shown that 

 in the equation JPv n =A , the values A and n were both con- 

 stant. The value n was found to be 



ZC p + W 6/c— 4 

 n ~ 2C P + 3C _ 5^3 ~~ 1 ' 101 ' 



where C p is the specific heat at constant pressure ; C is the 



(Pv\ . 

 constant for the gas, I Tp\ in heat units, and k is the ratio 



of the specific heats = 1.41. In other words the value of n 

 is constant for all gases. 



The equations of that paper enable one to draw some very 

 interesting conclusions concerning the nature of the primitive 

 solar nebula. 



If the nebulous gas be assumed to extend to an infinite 

 distance, and it be assumed that the condensation has reached 

 such a stage that the mass of the present solar system is in- 

 ternal to Neptune's orbit, we may compute by means of equa- 

 tions (19) and (20) the pressure and density at that radial 



* Presented by title to The Academy of Science of St. Louis, March 21, 

 1904. 

 t Trans. Acad, of Sc. of St. Louis, Vol. XIII; No. 5. 



(Ill) 



