208 On the Combination of Potassium and Oxygen. [Sept. 



be very great, if so vast an effect as that of cohesion be their 

 difference, when d is very little increased ; and since the repul- 

 sive force is corpuscular, and cannot operate between the large 

 spheres, the force must inevitably be enormously great, if the 

 hypothesis be true ; but none whatever is observed. 



Again : according to this hypothesis, take away the force of 

 repulsion, and that of attraction is very great, at a distance 

 equal to the distance between two adjacent particles ; increase 

 this distance (by breaking the solid) and the force totally 

 vanishes ; break rods of glass or other brittle matter at different 

 temperatures ; the same effect results ; but at different temper- 

 atures, the particles are at different distances from each other ; 

 therefore this force of attraction ceases to operate at different 

 distances, although the weight of the body does not vary. 

 Nothing need be said to prove that no such force is known to 

 exist ; it is totally unlike any force of which we can form an 

 idea ; for let a force vary inversely as any power or function 

 of the distance, the only place where a body can attract another 

 in such a manner that by increasing the distance by the smallest 

 quantity, the force shall vanish or be indefinitely reduced, is on 

 the surface ; but here we have to suppose one at a distance, 

 which cannot result from a variation according to any function 

 whatever of the distance (except the force increase directly as 

 some power of it, then cohesion would be produced at an infinite 

 distance), and this is not the only difficulty, for we have to sup- 

 pose this distance to be moveable. Hence this hypothesis is 

 more untenable than the other. Therefore we must suppose the 

 particles of solids to be in contact with eaoh other, and upon this 

 hypothesis it is impossible to see how the phenomenon in ques- 

 tion can be produced ; in fact, there is no parallel. In no case 

 of combination, where one of the bodies is solid, do we meet 

 with a condensation nearly so great as in this instance. Even 

 were we to suppose the particles of solids not to touch each 

 other, the condensation so very much exceeds that which takes 

 place in every other case, that we should naturally expect to find 

 some peculiarity in potassium, which gives rise to the anomaly, 

 which certainly appears to favour the supposition that potassium 

 is a compound of hydrogen and a base hitherto unknown. 

 However, future experiments only can ascertain the cause of so 

 singular a phenomenon ; and until experiments point out the 

 cause, whatever is supposed at present must be very uncertain 

 and unsatisfactory. 



