4 Trans. Acad. Set. of St. Louis. 



And hence we see that in condensing from a state of infinite 

 expansion the planet Jupiter has developed less than TofiV irffth 

 part of the heat produced by the condensation of the sun. 

 From this it is obvious that the sum of the potentials of all 

 the other planets upon themselves is very much smaller than 

 that of Jupiter alone ; and as the potential of the sun upon 

 itself is uncertain by at least twice the potential of Jupiter 

 upon itself, we may regard the potential of the sun upon 

 itself as furnishing sensibly all the energy developed by the 

 solar nebula in condensing from a state of infinite expansion. 

 Accordingly, having shown that (5) will give the total work 

 of condensation of the solar nebula, we may now express the 

 resulting energy in heat units. 



To elevate the temperature of a mass M of specific heat t, 

 B degrees centigrade, we require an amount of heat Mtd. 



We shall express the mechanical equivalent of the unit of 

 heat by Ag, in which A is the altitude through which a kilo- 

 gramme must fall, and g is the force of gravity. In French 

 measure Ag will be 424 Kilogrammeters. Then the resulting 

 heat developed by the falling mass will correspond to the 

 work, and we shall have 



W=MtdAg. (8) 



We may put T for W, and then for the condensation of 

 the sun we shall have 



3 M 2 r 2 q 



T - Mtd Aq = x eT — (9) 



* 5 R m v ' 



Accordingly, 



3 M r 2 1 

 = £ f£ L_ J_ (10) 



" 5 R m At K ' 



To determine 6 numerically, we make use of the following 



values : — 



M =330,000, 



m = 1, 



A = 424, (metres) 



r = 6,378,190, 

 R = 697,235,650, " 



t =jl (water). 

 Then 



0= 27,246,740° C. (11) 



