iv Advertisement. 



according to a different system ; and Gregory, with many 

 changes and substitutions, has been principally used in 

 that which is comprehended under hydrodynamics. 



This volume constitutes the first part of a course of 

 Natural Philosophy. The next, containing Electricity 

 and Magnetism, will be published in a few weeks. 



Cambridge, Sept 24, 1825. 



