10 pRiosTON — Radiating Phenomena in a Strong Magnetic Field. 



wliich fig. 3 corresponds to fig. 1, and fig. 4 to fig. 2. The action of the double 

 image prism is tlius to separate the middle from the side constituents, while, 

 at the same time, it possesses the advantage of showing all the constituents 

 simultaneously,* and shows each of them unblurred by overlapping with the 

 others. 



The question now before us is, can the quartet shown in fig. 2 be derived 

 from the triplet of fig. 1 by reversal of the central line .4, or does the doubling 

 of A depend upon other causes ? 



In answer to this question, as has been already remarked, the appearance of 

 the doublet A is against the reversal hypothesis, and it is further established 

 beyond all doubt, by means of my improved magnetic field, that the distance 

 between the components of A increases proportionately to the strength of the field 

 just as the distance between the side lines B and C increases with the strength of 

 the field. Further, when B and C are each a doublet or a trij^let, the distance 

 between the members of each of these doublets or triplets increases with the 

 strength of the field in the same direct ratio. In fact, as the strength of the 

 field increases, the system of lines which constitute A^ B, and C separate 

 laterally according to a uniform scale ; and, in face of these facts, the reversal 

 hypothesis becomes quite untenable. 



The general phenomenon, therefore, which remains to be explained is the 

 resolution of each member of the normal trij^let (fig. 1) into a doublet or a 

 triplet or some other system ; and, as we shall see immediately, the electro- 

 magnetic theory proposed by Dr. Larmor f may be extended to embrace all the 

 plienomena yet observed. Before proceeding to consider this explanation, 

 however, it may be well to refer briefly to a particular tjTpe of modification 

 which was recently announced as having been observed by. MM. Becquerel and 

 Deslandres,J and subsequently by Messrs. J. S. Ames, R. F. Earhart, and 

 H. M. Reese.§ This particular type is referred to by them as an examj)le of 

 "reversed polarization," that is a case in which the modified line shows as a 

 triplet in the magnetic field, but in whicli the vibrations in the centre line A are 

 parallel to the lines of force while the vibrations in B and are perpendicular 

 to the lines of force — the revei'se of the normal case. Stated in this way, the 

 phenomenon is very startling, and seems, at first sight, quite contradictory to all 

 theoretical expectations. But if we return to fig. 4, and take into consideration 

 the remarks already made, viz. that the components of A may be widely 



* This device was employed iudependently by the author and MM. Becq^ucrcl and Deslandres. 

 A double-image prism was also used, ia a different way by M. Coruu. 

 t Dr. J. Larmor, Phil. Mag., vol. xliv., p. 505, 1897. 

 t Comptes llendus, t. 126, p. 997, April, 1898. 

 § Astrophysical Journal, vol. viii., p. 48, June, 1898. 



