88 GAUSS AND WEBER ON TERRESTRIAL MAGNETISM. 



tween which they occur ; and the number of six terms, fixed on 

 as the rule for the annual publication, is completed by the addi- 

 tion of an extra term in August. 



Of the apparatus employed, three are exactly similar to those 

 at Gottingen, but of smaller dimensions ; namely, that of Dr. 

 Wenkebach, first used at the Hague, and subsequently at 

 Breda; the travelling apparatus with which M. Sartorius of 

 Waltershausen, and Dr. Listing, observed in Palermo, Catania, 

 and Messina ; and the apparatus already mentioned at p. 22, in 

 the Berlin Magnetic Observatory, which latter, however, will be 

 shortly replaced by a larger one, of Meyerstein's. The other 

 apparatus in Breslau, Freiberg, Gcittingen, Leipzig, Milan, Mar- 

 burg, Munich, and Upsala, are all alike. 



The participators in the observations represented in the six 

 terms, as far as the names have come to our knowledge, were 

 as follows : 



In Berlin, besides Prof. Encke, MM. Bremiker, Galle, Madler, 

 and Wolfers. 



In Breslau, besides Prof. V. Boguslawski and his sons, MM. 

 Bratke, Brier, Dittrich, Hiiniger, Jacobi, Isaac, Klingenberg, 

 Koch, Kiirber, Kiintzel, Maywald, Miiller, Dr. Pappenheim, 

 Reichelt, Reisern, Ribbeck, Riemann, Roedsch, Wiedemann, 

 and Wilde. 



In Catania, Dr. Listing, MM. Sartorius von Waltershausen, 

 and Zobel. 



In Freiberg, besides Prof. Reich, MM. Feigner, Neubert, 

 and Walther. 



In Gottingen, MM. Brass, Lieut. Engelhard, Dr. Goldschmidt, 

 Meyerstein, Schroter, Dr. Stern, Lieut, von Stolzenberg, Prof. 

 Ulrich, Dr. Wappaus, Dr. E. Weber, and Prof. W. W^eber. 



At the Hague, (in the September term,) besides Dr. Wenke- 

 bach, MM. von Cranenburgh, Rueb, and Simons. 



In Leipzig, besides Prof. Mcibius, MM. Brandes, Faber, Hiilse, 

 Kiihne, Michaelis, Netsch, and Zunck. 



In Milan, besides M. Kreil, MM. Capelli, Stambucchi, and 

 Delia Vedova. 



In Marburg, besides Prof. Gerling, MM. Beck, Deahna, Eich- 

 ler, Fliedner, Hartert, Hartmann, Ise, Kutsch, Landgi'cbe, Lotz, 

 and Oppermann. 



In Messina, Dr. Listing, MM. Sartorius von Waltershausen, 

 and Tardy. 



