612 Foreign and Miscellaneous Intelligence. 



one in a place so remote as Kasan ? From the position of these two 

 places, it is obvious that these irregularities cannot in any way be 

 connected with the diurnal motion of the sun, as the hourly variations 

 obviously are. What is most remarkable in the irregular variations 

 is, that the motion of the needle is much more frequently towards the 

 east than in the contrary direction. 



From a series of observations on the irregular variations at dif- 

 ferent places, M. Kupffer has discovered that there is a regular 

 period during the night in which the needle has a uniform movement 

 as it has during the day. He finds that at St. Petersburg!! the needle 

 marches towards the west from nine o'clock in the evening till almost 

 one o'clock in the morning ; that the arc travelled over by the needle 

 is three minutes, whereas the diurnal arc travelled over from nine in 

 the morning till two in the afternoon is nearly fifteen minutes at 

 St. Petersburg!!, and twelve at Kasan. The observations have been 

 chiefly made at the same moment at St. Petersburgh, Nicolai'eff, and 

 Kasan ; and such is the coincidence, that choose any hour in a whole 

 table of observations, at which the needle has suffered irregular oscil- 

 lations at St. Petersburgh, and it will be found to have suffered simi- 

 lar perturbations at Nicolai'eff. In a long series of observations, 

 only two exceptions have been found to this general rule. The 

 author observes, the sign of the diurnal variation changes in crossing 

 the irregular line called the magnetic equator, and gives a simple rule 

 for remembering the direction in which the daily variation takes 

 place. ' If we stand at the southern extremity of the needle, in the 

 northern magnetic hemisphere, with the face to the needle, its north 

 pole turns towards the left from eight o'clock in the morning till two 

 in the afternoon ; the same thing takes place from eight o'clock in 

 the evening till two in the morning ; but from two o'clock till eight, 

 whether in the morning or evening, it marches towards the right. 

 Over the whole of the southern magnetic hemisphere, the periods are 

 the same, but the deviations are in the opposite directions.' The 

 author remarks, that the extent of the hourly variations depends on 

 the length of the projection of the needle on the plane of the 

 magnetic equator ; that in all probability it depends on the diurnal 

 revolution of the magnetic equator, and is probably a phenomenon 

 closely allied to those of revolving discs of metal discovered by 

 M. Arago*. 



II. CHEMICAL SCIENCE. 

 \ 



1. MATTEUCI ON THE ORIGIN OF THE ACTION OF THE VOLTAIC PILE. 



A HIGHLY important discussion is at present in progress, relative to 

 the original source of electricity in the voltaic pile, not originating 

 with, but to a considerable extent renewed by, the endeavours of 

 M. A. de la Rive, to prove that chemical action is the sole cause ; 



* Voyage dans les Environs du Mont Elbrouz dans le Caucase. Par M. Kupffer, 

 Membre de 1' Academic des Sciences de St. Petersbourg. 



