174 ON THE INTERACTION OF NATURAL FORCES. 



- of the radius of the sun would generate work in a water 

 10000 



mass equal to the sun, equivalent to 2,861 degrees Centigrade. 

 And as, according to Pouillet, a quantity of heat corresponding to 

 1 degree is lost annually in such a mass, the condensation 

 referred to would cover the loss for 2,289 years. 



If the sun, as seems probable, be not everywhere of the 

 same density, but is denser at the centre than near the surface, 

 the potential of its mass and the corresponding quantity of heat 

 will be still greater. 



Of the now remaining mechanical forces, the vis viva of the 

 rotation of the heavenly bodies round their own axes is, in 

 comparison with the other quantities, very small, and may be 

 neglected. The vis viva of the motion of revolution round the 

 sun, if fj. be the mass of a planet, and p its distance from the 

 sun, is 



K 



Omitting the quantity x~ as very small compared with ^-, and 

 dividing by the above value of Y, we obtain 



L = 5 p 

 V 3 M' 



The mass of all the planets together is - of the mass of 



738 



the sun ; hence the value of L for the entire system is 



