The great body of population dynamics, like those of the motion of the celestial bodies, can be solved-and what is most remarkable, there is a surprising analogy between the formulas employed in these calculations. I believe that I have achieved to some extent what I have long said about the possibility of founding a social mechanics on the model established by celestial mechanics-to formulate the motions of the social body in accordance with those of celestial bodies, and to find there again the same properties and laws of conservation.