96 GAUSS AND WEBER ON TERRESTRIAL MAGNETISM. 



ceased. The disentanglement of the comphcations which thus 

 occur in the phaenomena at every individual station, will un- 

 doubtedly prove very difficult ; nevertheless, we may confidently 

 hope that these difficulties will not always remain insuperable, 

 when the simultaneous observations shall be much more widely 

 extended. It will be a triumph of science, should we at some 

 future time succeed in arranging the manifold intricacies of the 

 pheenomena, — in separating the individual forces of which they 

 are the compound result, — and in assigning the source and mea- 

 sure of each. Now and then we find at some places a small 

 change, without any apparent counterpai-t at any of the other sta- 

 tions. Such occurrences ought not to be at once looked upon 

 as evidences of local magnetic action. In so gi^at a mass of 

 numbers an error may sometimes take place. Cases have fre- 

 quently occurred to us where a revision of the original observa- 

 tions, when these were in "our hands, has shewn an error of cal- 

 culation in the reduction, or an evidently accidental error in the 

 writing. In other cases, in which we had received only an ex- 

 tract of the observations, a reference to our correspondent has 

 led to a similar conclusion. As, however, it is impracticable to 

 discuss all such cases by correspondence, those obsei-vers who 

 do not communicate the original obsei-vations are requested, 

 when they discover such cases in the cm^es representing them 

 (as, for instance, at Leipzig, on the-26th of November, 1836, 

 for 6'^ 15™ Gottingen mean time), to refer to the original re- 

 gister. If errors are thus discovered, they can be corrected in 

 a following number. Even when the original papers do not 

 decidedly indicate any error, yet we cannot have perfect assu- 

 rance with respect to cases which rest only on a single set of ob- 

 sei*vations : it may happen, even to a practised observer, to wi'ite 

 down in the same set repeated eiToneous decimals. By such 

 a conjecture, (somewhat hazarded it is time,) the above-men- 

 tioned number 11*69 would be reduced to 6*69, and thus corre- 

 spond with the others. 



But supposing the case of such an insulated movement to be 

 established beyond all doubt, it does not follow that it is to be 

 considered as local in the most limited sense. As the source of 

 every anomaly must have its seat somewhere, it may be that 

 the disturbing force is in the neighbom'hood of the station it- 

 self. If feeble, i< s action may still be perceptible at that station, 

 on account of its proximity, and may disappear (i. e. be no longer 



