260 On the Tendency of 



law observed by inelastic fluids ; but he 

 suggests that *' if two kinds of air of very 

 *' different specific gravities, were put into the 

 '* same vessel, with very great care, without 

 '^ the least agitation that might mix or blend 

 " them together, they might continue separate, 

 ** as with the same care luine and water may 

 " be made to do." 



The determination of this point, w^hich 

 seems at first view but a trivial one, is of con- 

 siderable importance ; as from it we may ob- 

 tain a striking trait,, either of the agreement or 

 disagreement of elastic and inelastic fluids in 

 their mutual action on each other. 



It is, therefore, the subject of the following 

 experiments to ascertain whether two elastic 

 fluids brought into contact, could intermix 

 with each other, independently of agitation. 

 The result seems to give it in the affirmative 

 beyond a doubt, contrary to the suggestion of 

 Dr. Priestley ; and establishes this remarkable 

 fact, that a lighter elastic fluid cannot rest 

 upon a heavier, as is the case with liquids ; 

 but, they are constantly active m diffusing 

 themselves through each other till an equi- 

 librium is effected, and that without any regard 

 to their specific gravity, except so far as it 

 accelerates or retards the effect, according to/ 

 ck*c»nastanc'es. 



