[ 1 6 ] [BookL 



C II A P. IV. 



OF ATTRACTION AND REPULSION. 



)?ive Kinds of AttraSicn.Cobefion-^-Combination Cryftallixatim 

 explained. Grai-i'.aiioii Specif Gravity, what. Magnetic and 

 elettrical Attraction. Rep:d.. 



IT has been found by experience, that all matter, of 

 whatever kind, is fubject to certain general laws; 

 and the principal of thefe are attraction and repul- 

 fion. Five different kinds of attraction have been 

 enumerated by modern philofophers. i. The at- 

 traction of cohefion ; 2. Of combination, or, as it is 

 called by chemilb, elective attraction j 3. Gravity j 

 4. The magnetic attraction; and, 5. The attraction 

 bf electricity. Whether the fame principle acts in 

 ail thefe cafes; Or whether each of thefe effects de- 

 pends upon a diftinct caiife; human fagacity has not 

 been able to difcover ; nor is there any inftance in 

 which the principle of attraction feems to approach to 

 the nature of a general law, except in that of gravity j 

 and yet even this is not without an exception j fmce 

 by every experiment that we liave hitherto been able 

 to make, there is no reafon to believe that the element 

 of fire, or heat, is fubject to the common laws of gra- 

 vitation. Unlefs, therefore^ it could be proved that 

 the principle of attraction is the fame in all thefe cafes 

 that have been enumerated, we, perhaps, arc fcarcel7 

 correct in confidering it as a general property of 

 matter; and even fuppofing the caufe to be the fame, 

 it rriay, after all, belong rather to fome particular fpe- 

 cies of matter^ which acts upon or impels all other 

 bodies, than to mdtter in general. 



I. The attraction of COHESION may be obferv- 

 cd in aliroft all the 'common operations of nature, 



and 



