THE STABILITY OF THE SOLAR SYSTEM 301 



years later, utilising these same methods, the theory was to 

 receive at the hands of Leverrier and Adams a brilliant and 

 clinching verification in the discovery of a new and unsuspected 

 member of the solar system. 



This tacit partnership, undisturbed by the pitiful jealousies 

 which disfigure so many pages of scientific history, closed with 

 the death of Lagrange in 1813. He was almost wholly a mathe- 

 matician. The range of Laplace was larger. He extended and, 

 through wider applications, gave almost new life to the Theory 

 of Chance that is, the calculus of probabilities. He was asso- 

 ciated with the chemist Lavoisier in many of the latter's in- 

 vestigations. Together they produced an important memoir, 

 which is one of the foundations of the modern theory of heat. 

 Lagrange speculated little ; the mind of Laplace was sometimes 

 given to wider flights. It was in one of these that he divined 

 and sketched the grandiose conception which endeavours to 

 account not merely for the present motions and actions, but 

 the origin of worlds as well. He was not alone in working 

 out this theory ; though he did not know it, he had a precursor 

 in a near contemporary. Moreover, he threw it out as little 

 more than a suggestion, at the close of the theoretical portion 

 of his more popular Exposition du Systtme du Monde. The 

 evidence which has given weight and prevalence to the Nebular 

 Hypothesis has largely come since his day ; with it some diffi- 

 culties which he could in no wise foresee. This, assuredly one 

 of the profoundest flights of the human imagination, may well 

 form matter of a later discussion. 



Thanks to Newton, we know what makes the world go. 

 Thanks to Laplace, we know with precision how it goes. How 

 large is this machine ? 



