Intelligence and Miscellaneous Articles. 



423 



Another fact, which has since created some interest, w a s also dis- 

 covered hy me whilst experiment- 

 ing with the same apparatus. I ob- u » 



served that when the compass 

 needle was placed above the poles 

 of the voltaic magnet, as in fig. 2. 

 on breaking the connexion with 

 the voltaic battery, the needle was 

 suddenly deflected half a revolu- 

 tion from its previous position ; on 

 restoring the connexion the needle 

 completed its revolution in con- 

 tinuation : by timing the operation 

 a continuous rotatory motion was 

 produced in the needle in various 

 positions (and also in several needles 

 at the same time) adjacent to the 

 voltaic magnet. 



This rotatory effect is well known 

 to all who have repeated Oersted's 

 original experiment, in which the 

 voltaic wires alone are used to af- 

 fect the needle. 



This rotatory motion was applied 

 lately (and described in your va- 

 luable Journal for July) to an 

 apparatus copied from that con- 

 structed by Mr. Saxton, which construction is merely a modifica- 

 tion of one invented by Professor Ritchie, and exhibited two years 

 ago by his assistant (my late talented and ingenious friend Francis 

 Kirby of the London University). Professor Ritchie described his 

 apparatus in the Philosophical Transactions, part ii. p. 319. The 

 only difference between them is, that invented by the learned Pro- 

 fessor makes the voltaic magnet rotate, while that of Mr. Saxton 

 causes the steel magnet to rotate. 



39, Charles-street, Parliament-street, 

 August 1835. 



E.M.Clarke. 



LETTER OF PROFESSOR ROSENBERGER TO THE EDITOR OF THE 

 ASTRONOMISCHE NACHRICHTEN J WITH AN EPHEMERIS OF 

 HALLEY's COMET. 



The positions refer to the mean equinox of the 16th November, 

 1835. Regard has already been had to the aberration, through the 

 change of time, which is the foundation of the calculation (mean noon 

 Berlin). The elements are those transmitted on the 6th of October, 

 namely, 



log. a = 1-25498073, e = 0*96744336, 



- T=Nov. 1605351 m. t. Berlin. 



n = 55° 1 1' 21"-40 w = 1 10° 43' 59"'42 i = 162° 9' 48"*53. 



