Br Biichner^s Hypothesis regarding Magnetism. 237 



or rather to some defect of equilibrium in their chemical consti- 

 tution ? Of this we are ignorant. It seems to me, that it may 

 be admitted, that, as light emanates from the sun toward the 

 earth, magnetism in return emanates from the earth toward the 

 sun, in a state of neutralization in the equatorial zone, which 

 receives the greatest quantity of light, and in a state of polariza- 

 tion toward the poles of the globe, which receive the least of it. 

 It cannot be refused to admit, that light, caloric, electricity and 

 magnetism, are in a certain mutual relation of causality : the ques- 

 tion is merely, what is this relation ? The following hypothesis 

 appears to me the most simple and most natural. 



" The planets receive from the sun light and electricity in the 

 neutral state ; they decompose these principles, and reproduce, 

 in their turn, caloric, and the two polarised electric principles. 

 But caloric dilates bodies, and breaks in them the equilibrium 

 of their cohesion, and of their chemical constitution. Then ca- 

 loric itself undergoes a modification, which is stiil enigmatical to 

 us, in virtue of which it is transformed into magnetism. All 

 ponderable bodies are conductors of magnetism, for which they 

 appear to have little affinity. Organised and living bodies, such 

 as our own, are sensible to light and heat ; but we want a sense 

 for the magnetism with which we are constantly surrounded and 

 penetrated : hence the difficulty of understanding this agent 

 aright. If we inhabited the sun, perhaps, in place of a sense 

 for perceiving light, we should possess a sense for perceiving 

 magnetism. 



", In the present hypothesis, magnetism would not emanate 

 from the earth only, but also from all bodies in the universe that 

 are illuminated hy the sun. We may consider as proofs of these 

 magnetic emanations; 1^^, The magnetic currents which are 

 established in the conducting wire of an electro-chemical appa- 

 ratus, or in a thermo-magnetic metal ; for the earth itself, con- 

 sidered in this point of view, is nothing else than a great thermo- 

 magnetic apparatus ; and, S^/z/, the circumstance that, in the most 

 elevated regions of the earth's atmosphere which man has hither- 

 to been able to attain, the magnetic needle remains as strongly 

 polarised as at the very surface of the globe. 



" Further, if we reason according to the ordinary laws of na- 

 ture, we cannot regard it as probable that the planets, placed as 

 they are right opposite to the sun, act an entirely passive part. 



