46 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ter is indeed changed very slightly ; that it is impossible for 

 him to escape the conviction that the seat of the selective 

 absorption which produces the Frauenhofer lines is below the 

 envelope which exerts the general absorption shown by the 

 diminished brightness of the borders of the solar disk. But 

 the phenomena of the solar faculse, or bright spots, prove that 

 the exterior envelope is very thin, and rests upon the photo- 

 sphere, whence Hastings concludes, from both these prem- 

 ises, that the origin of the Frauenhofer lines must be in the 

 photosphere itself, in accordance w^ith Lockyer's views. A 

 farther modification of this apparatus has enabled Hastings 

 to bring into the same field of view the sj^ectra of two oppo- 

 site edo:es of the sun. The rotation of the sun on its axis 

 was then very clearly demonstrated by its effects on the 

 spectral lines, their relative positions being manifestly dis- 

 placed by reason of the change in the refrangibility, due to 

 the fact that one limb of the sun was approaching while the 

 other was receding from the observer. 4 D, 1873, 369. 



THE CONNECTION BETWEEN MAGNETISM, AUEOKAS, AND 



SOLAR SPOTS. 



Professor Loomis, the well-known meteorologist, has made 

 a careful comparison between the relative extent of solar 

 spots, the diurnal inequality of the magnetic declination, and 

 the number of auroras so far as they have been catalogued 

 from the year 1776 to the year 1872, and his conclusions 

 may be stated as follows : 



A diurnal inequality of the magnetic declination, amount- 

 ing at Prague to about six minutes, is independent of the 

 changes in the sun's surface from year to year. The excess 

 of the diurnal inequality above six minutes, as observed at 

 Prague, is nearly proportional to the amount of spotted sur- 

 face upon the sun, and may therefore be inferred to be pro- 

 duced by this disturbance of the sun's surface, or both dis- 

 turbances may be ascribed to a common cause. The corre- 

 spondence between the auroral curve and the sun's spot 

 curve, thouo'h not as close as between the macjnetic curve 

 and the sun's spot curve, is certainly quite remarkable. In 

 only two cases is there any sensible difference in the dates 

 of minimum of the two classes of phenomena. There is, how- 

 ever, some disaccordance between the dates of maximum, 



