VIIL] -Cjp j&imtific &pjerte xrf f) 0s5fibhmi. 167 



successive steps in the ladder of knowledge, as M. 

 Comte would have us believe, but three branches 

 springing from the common stem of molecular physics. 



As to astronomy, I am at a loss to understand how 

 any one who will give a moment's attention to the 

 nature of the science can fail to see that it consists of 

 two parts : first, of a description of the phenomena, 

 which is as much entitled as descriptive zoology, or 

 botany, is, to the name of natural history ; and, secondly, 

 of an explanation of the phsenomena, furnished by the 

 laws of a force gravitation the study of which is as 

 much a part of physics, as is that of heat, or electricity. 

 It would be just as reasonable to make the study of 

 the heat of the sun a science preliminary to the rest 

 of thermotics, as to place the study of the attraction of 

 the bodies, which compose the universe in general, 

 before that of the particular terrestrial bodies, which 

 alone we can experimentally know. Astronomy, in fact, 

 owes its perfection to the circumstance that it is the 

 only branch of natural history, the phsenomena of which 

 are largely expressible by mathematical conceptions, 

 and which can be, to a great extent, explained by the 

 application of very simple physical laws. 



With regard to mathematics, it is to be observed, in 

 the first place, that M. Comte mixes up under that 

 head the pure relations of space and of quantity, which 

 are properly included under the name, with rational 

 mechanics and statics, which are mathematical deve- 

 lopments of the most general conceptions of physics, 

 namely, the notions of force and of motion. Eelegating 

 these to their proper place in physics, we have left pure 

 mathematics, which can stand neither at the head, nor 

 at the tail, of any hierarchy of the sciences, since, like 

 logic, it is equally related to all ; though the enormous 

 practical difficulty of applying mathematics to the more 



