260 Magnetic Influence of Solar Light, 



A glance at the two concluding columns of this Table will 

 shew a very decided magnetic effect due to the presence of 

 the steel wire, to the extent of from 5 to 6 seconds of in- 

 crease of intensity in the time of performing ten oscillations. 

 Accordingly, on approximating the wire to the unmagnetic 

 testing needle, immediate, though certainly not very strong, 

 attraction between the two was exhibited, the needle freely 

 following the wire through considerable arcs, and by apply- 

 ing the magnetic testing needle, it was found that each oxida- 

 ted part had become a north, each polished part, a south 

 pole. This distribution of the polar forces, is precisely the 

 converse of that obtained by Baumgartner, but is conforma- 

 ble to some of the cases observed by Moser and Reiss. In 

 using the magnetic needle as a means of discovering the 

 kind of magnetism that may be resident in any part of a 

 magnetised body, it is only necessary to bear in mind, that 

 like poles repel, unlike poles attract each other. In the 

 present instance it was observed, that on approaching the 

 north pole of the testing needle to the oxidated parts of the 

 wire immediate repulsion was manifested, indicating the 

 presence of polarity like in kind to itself, while on ap- 

 proaching it to the polished parts, attraction ensued, shew- 

 ing unlike, or southern polarity. 



While these results indicate with perfect clearness the 

 truly magnetic condition of the steel wire, there are certain 

 points now to be mentioned, which make it exceedingly 

 doubtful whether this was due to the action of solar light. 

 The method of observation employed was, in the first place, 

 objectionable, as it does not shew the condition of the wire 

 previous to exposure, a point of most essential importance, 

 since its having been left undetermined, renders it doubtful 

 how much of the effect on the testing needle was really due to 

 the exposure of the wire, how much to the previous state of 

 the wire itself. It was further found that during exposure, 

 the wire had been inadvertently placed in the magnetic 



