1 4 Dr. Hare's reply to Professor Olmsted. 



and of course, to two poles of the compound particle form- 

 in <*• water. Elevation of temperature may favor this change 

 by its mysterious influence on the electric polarities of the 

 particles ; as in the case of the tourmaline : — or because the 

 enlargement of the calorific atmospheres, renders the preser- 

 vation of their independency more difficult. 



That caloric is alternately an exciting cause of combina- 

 tion, and decomposition, we all know. Mercury is oxydised 

 at one temperature, and revived at another. At one tempe- 

 rature hydrogen yields chlorine to silver, at another, decom- 

 poses the chloride of that metal. At a low temperature, 

 potassium absorbs oxygen more greedily than carbon, or 

 iron, while the reverse is true, when these are heated to in- 

 candescence. I have long suspected that heat promotes and 

 modifies chemical action, by influencing electrical polarities. 

 The elements of water are severed by the voltaic poles. If 

 in this case their polarity is influenced in one way, elevation 

 of temperature, when it causes their reunion, must have an 

 opposite effect, and of course must influence polarity. 



I suppose in this case a change in the attractive power of 

 the poles, of combining atoms, analogous to that which may 

 be induced in iron bars, which attract or repel each other ac- 

 cordingly as the magnetism communicated to their poles, is 

 alike or unlike. 



Platina sponge, a cold metallic mass, is found to cause the 

 union of the hydrogen and oxygen in a gazeous mixture : 

 yet it is utterly inconceivable that the presence of inert par- 

 ticles, combining with neither of the elements of water, can 

 cause an increase of attraction between them. 



That the phenomena just alluded to, belong to a depart- 

 ment of chemistry, with which we are but imperfectly ac- 

 quainted, I admit ; but on that very account inferences, 

 founded on them, ought not to be allowed to invalidate the 

 demonstration, of which the existence of a material cause of 

 heat is, upon other grounds, susceptible. 



Professor Olmsted cannot discover that there is 



" Any more difficulty in conceiving why a heated body should 

 communicate its influence to another body without the aid of air, 

 than why the Sun should communicate his attractive influence to Sa- 

 turn or Uranus without the aid of such a medium 31 ! ! ! 



It would seem then that Professor Olmsted is of opinion, 

 that the planets owe their power of attracting each other, and 

 all the bodies on or near their surfaces to the Sun, as they 



