188 C. F, GAUSS ON THE GENERAL THEORY OF 



nal in reference to the earth. We may hope, that from the ge- 

 neral attention now directed to these phaenomena, much light 

 may shortly be throA^Ti upon their causes. But it should not be 

 forgotten that these changes are comparatively very small, and 

 that there must therefore exist a much more powerful and con- 

 stantly acting principal force, of which we assume the seat to be 

 in the earth itself. A consequence which follows from this con- 

 sideration is, that the facts which are to serve as the foundation 

 on which the study of the principal force must be based, ought 

 properly themselves to be first freed from the effects of the ano- 

 malous changes. This can only be done by mean values, drawn 

 from numerous and continued observations ; and until we shall 

 possess such purified results, from a great number of stations di- 

 stributed over the whole surface of the globe, the utmost that can 

 be looked for is an approximation, in which there must still re- 

 main differences of the order of these anomalies. 



2. 



The foundation of our researches is the assumption, that the 

 terrestrial magnetic force is the collective action of all the mag- 

 netized particles of the earth's mass. We represent to ourselves 

 magnetization as a separation of the magnetic fluids. Admitting 

 this representation, the mode of action of the fluids (repulsion 

 of similar and attraction of dissimilar particles inversely as the 

 square of the distance) belongs to the number of established 

 physical truths. No alteration in the results would be caused 

 by changing this mode of representation for that of Ampere, 

 whereby, instead of magnetic fluids, magnetism is held to con- 

 sist in constant galvanic currents in the minutest particles of 

 bodies. Nor would it occasion a difference if the terrestrial 

 magnetism were ascribed to a mixed origin, as proceeding partly 

 from the separation of the magnetic fluids in the earth, and partly 

 from galvanic currents in the same ; inasmuch as it is known, 

 that for each galvanic current, may be substituted such a given 

 distribution of the magnetic fluids in a surface bounded by the 

 current, as would exercise in each point of external space pre- 

 cisely the same magnetic action as would be produced by the 

 galvanic current itself. 



3. 



For the measurement of the magnetic fluids we take, as in 



