470 PRINCIPLES OF CHEMISTRY 



'flupposs that in their movements, when heavy ones take the place of those 

 that are lighter, similar changes take place, provided that the system or the 

 molecule is preserved throughout the change. 



It seems probable that in the heavenly systems, during incalculable 

 astronomical periods, changes have taken place and are still going on similar 

 ta those which pass rapidly before our eyes during the chemical reaction of 

 molecules, and the progress of molecular mechanics may we hope will in 

 course of time permit us to explain those changes in the stellar world which 

 have more than once been noticed by astronomers, and which are now so 

 carefully studied. A coming Newton, will discover the laws of these changes. 

 Those laws, when applied to chemistry, may exhibit peculiarities, but these 

 will certainly be mere variations on the grand harmonious theme which 

 reigns in nature. The discovery of the laws which produce this harmony in 

 chemical evolution will only be possible, it seems to me, under the banner 

 of Newtonian dynamics, which has so. long waved over the domains of 

 mechanics, astronomy, and physics. la calling chemists to take their stand 

 under its peaceful and catholic shadow I imagine that I am aiding in estab- 

 lishing that scientific union which the managers of the Boyal Institution 

 wish to effect, who have shown their desire to do so by the flattering invita- 

 tion which has given me a Bussian the opportunity of laying before the 

 countrymen of Newton an attempt to apply to chemistry one of his immortal 

 principles. 



