Nipher — On Gravitation in Gaseous Nebulae. 67 



be very much smaller than would be the case in the atmos- 

 phere of the hydrogen sun. In fact the pressure of gases of 

 all kinds in interplanetary space must be practically obliter- 

 ated, by reason of the low temperature. The facilities for 

 refrigeration on the outskirts of our universe seem to be 

 very effective. And this may also serve to aid in under- 

 standing the conditions existing on the sun. 



If the gaseous mass here discussed were initially under 

 isentropic conditions, it would remain in equilibrium. It 

 could not contract, nor could its temperature change. If it 

 be assumed to lose heat with equal facility from all parts, it 

 will contract and the temperature will rise uniformly through- 

 out. The greater the heat loss per second, the more rapidly 

 will the mass pass through its history of condensation. If 

 heat escapes from the denser parts near the core, with less 

 facility than from the less dense parts, then the temperature 

 throughout the mass at any instant may become a function 

 of the radius. This seems to be the condition around our 

 own sun. 



A gas having greater density than hydrogen, under stand- 

 ard conditions, would have a proportionately smaller con- 

 stant (7. 



The temperature computed above for the hydrogen sun 

 would be proportionately greater than 20,000,000 degrees. 

 Equation (23) in fact shows that for a fixed radius R of 

 spherical core, in such a gaseous mass, and containing a 

 given internal mass M, the product T C is constant for all 

 gases. Hence, d and P at the surface of the sphere, com- 

 puted numerically for the hydrogen mass, would have the 

 same numerical values for any other gas, under the conditions 

 which this entire discussion assumes. 



The average density of the entire spherical mass would 

 then be independent of the nature of the gas, and would be 

 1.296 grammes per cubic centimeter, as was above shown. 



The conditions surrounding our own sun do not appear to 

 differ in a way that can negative the conclusion that, in 

 order to account for its increased average density and low 

 temperature, some liquid condensation may be assumed 

 to have already taken place. With the law of gase- 



