Progress of Foreign Science. 337 



During an aurora borealis, he made a series of observations 

 from noon to noon without intermission, which evidently shewed 

 that this meteor displays an enfeebling operation on the magnet; 

 proving in this respect, the connexion between electricity and 

 magnetism *. From analogous researches he has been led to 

 infer, that the magnetic intensity is always impaired when the 

 moon passes through the equator. 



During a residence of a few days last year in Copenhagen, 

 M. Hansteen lodged in the round tower, which serves as an 

 observatory. As he was repeating here the above-described 

 observations on the vibrations of his horizontal needle, he found, 

 to his great astonishment, that for 300 vibrations not less than 

 836.57 ' were required : and in a garden contiguous to the 

 tower, only 779' for the same number of oscillations. This 

 tower is 126 feet high, with very thick walls, and has, built in its 

 centre or axis, a hollow cylinder, round which the stair winds 

 in 7 convolutions. After he had made several observations 

 below, which shewed that the mean period of 360 vibrations 

 was 787', he returned to the tower, and found the following 

 duration of 300 oscillations; first, aloft on the tower ; then at 

 regular stages of descent to the bottom : 



Top. 1st platform 3. 4^. 6^. bottom 



842.37 836.57 837.3 834.43 804.07 813.0. 



Not a little astonished at these results, he continued his ob- 

 servations, and deduced at last the general result, that at the 

 under end of every perpendicular body the magnetic needle 

 oscillates quicker when it is placed northward of the body, or 

 when it presents its south pole to it ; but that It oscillates more 

 slowly when placed southward of the body, so as to present its 

 north pole to it. And inversely, it was found, that, at the upper 

 extremity of the vertical body, the needle vibrated always slower 

 on the north side, and quicker on the south side. He 

 thence concludes, that every perpendicularobject, of whatsoever 

 matter composed, possesses at its upper end a magnetic south 

 pole, and at its under end a magnetic north pole. This result 

 IS of such importance, that we hope some of our philosophers 

 and astronomical observers, accustomed to minute precision of 

 research, will verify these experiments of the learned Dane. 



From a comparison of Col. Beaufoy's observations on the mag- 

 netic declination needle, M.Arago has shewn, that, since the month 

 of April, 1819, the direction of the movements of the needle 



variationi are unfavourable to such an annual change as the Norwegian 

 Professor iiidicatvii. 



♦ Baron liuinlxililt made a similar remark some years ago at Berlin ; 

 but uiilitiiS tlie obscrvutiuuR of the horixoutal needle be combined with 

 siuiuliaueouH (ibscrvations of the <iij)jiiug-ncedle, the variation of iutcusity 

 cauuut be held to be deuioustratcd. 



