26 ANNUAL RECOKD OF SCIENCE AND INDUSTRY. 



nucleus shows that the repulsive force is exerted, not only 

 between the sun and the tail, but also between the separate 

 atoms of which the tail is formed. Since, thus, repulsion is 

 proved, and even apparent as we may say, we must attach 

 some value to the determinations that have been made by 

 Bcssel, Pape, and Bond, who were obliged to make certain 

 hypotheses as to the development of the tail, while, on the 

 other hand, the third comet of 1862, like many others, seems 

 to have developed its tail in such a manner that we have at 

 present no safe foundation for computing the amount of the 

 repulsive force existing therein. 19 C, VIIL, 109. 



PECULIAR AURORAL PHENOMENA. 



The nature of the auroral light is the subject of a com- 

 munication by Lemstrom, who concludes that the white flam- 

 ing appearances occasionally seen on the summits of mount- 

 ains iu Spitzbergen and in Lapland are of the same nature 

 as the northern lights. Similar appearances have also been 

 seen in other parts of the world. Electrical currents that 

 develop themselves in the earth when the auroras are present 

 are not induction phenomena caused by the atmospheric 

 auroral currents, at least not in northern regions. 19 (7, VII., 

 383. 



THE SPECTRUM OF THE AURORA BOREALIS. 



The late Professor Angstrom, who at no time accepted the 

 theory that the spectra of gases varied with the pressure and. 

 temperature and chemical process, advanced the opinion that 

 the spectrum of the aurora borealis is composed of two dif- 

 ferent superposed spectra, the one consisting of extremely 

 feeble bands of light, belonging to the spectrum of the nega- 

 tive pole, the other consisting of a single strong yellow line, 

 which is characteristic of the aurora, and which, Angstrom 

 believed, owes its origin to fluorescence or phosphorescence. 

 12.4, X., 211. 



THE GEOGRAPHICAL DISTRILUTION OF AURORAS. 



Iii a recent paper in Petermann's geographical notices, 

 Professor Fritz, of Berne, gives the results of his researches 

 into the geographical distribution of auroras. Having as far 

 as possible eliminated the sources of error arising from the 



