750 REPORT— 1898. 



convinced me of tlie advantap:e wliicb would be gained if Captain Chaves, 

 Director of the Meteorological Observatory of Ponte Delgada, came to Europe to 

 study the practical details of the magnetic service there. I therefore communicated 

 my ideas to the Portuguese Government, who recalled Captain Chaves to undertake 

 a mission in this sense. 



Captain Chaves, after having finished bis studies at the observatory of St. Maur 

 under the enlightened direction of M. Moureaux, has pointed out to me the 

 importance of taking the present opportunity of magnetically reconnoitring the 

 archipelago, as a preliminary to the definitive installation of the observatory. 

 This would be useful, not only to determine the value of the difi'erent magnetic 

 elements, till now almost unknown,^ but besides, to determine in the island of 

 St. Michael, Avhich appears likely to present conditions favourable to the installa- 

 tion of the central observatory of the Azores, the locality most suitable for the 

 combined services of meteorology and magnetism. 



Feeling certain that the views of Captain Chaves are just, and well knowing his 

 competence, being also aware that the Portuguese Geodetic Commission finished 

 last year the survey of the island of St. Michael, and that this year it will finish 

 the survey of the neighbouring island of Santa Maria, I have resolved to under- 

 take the charge of the above-mentioned magnetic reconnaissance. 



With this end I am now having the necessary instruments constructed ; and I 

 announce to the International Commission that I hope to be able to put Captain 

 Chaves in the position to be able to commence the magnetic reconnaissance of the 

 Azores towards the month of April of next year. 



8. On Magnetic Observatories in Cape Colony. By Dr. Beattie 



and Mr, Morrison. 



9. Sur le MoiLvement diurne dtt, Pole Nord d'un Barreau Magnetique 

 suspendu par le centre de gravite. Par J. B. Capello. 



[PLATES VI.-VIIL] 



En combinant les variations diurnes de Tinclinaison avec celles de la decli- 

 naison, sur un plan perpendiculaire a, la direction de I'inclinaison, r^sulte line 

 courbe fermtSe. 



Les variations oii ecarts de I'inclinaison sout positives vers le sud, et celles de 

 la dSclinaison positives vers I'ouest. 



II faut avertir que les ecarts de la declinaison doivent etre multiplies par le 

 cosinus de I'inclinaison, afin de les projeter sur un plan perpendiculaire a la meme 

 inclinaison. 



II est interessant de comparer ces courbes obtenues en divers points on stations 

 du globe. 



La 1"® Planche contient les courbes de Kew, Paris (Pare S' Maur), Perpignau 

 et Lisbonne en 1894 et 1895. 



Les courbes de Kew et de Lisbonne sout deduites des jours trauquils (cinq 

 jours choisis a chaque mois), celles de Paris et de Perpignan sont dt^duites de tcus 

 les jours. 



La 2^™® Planche contient les courbes de Lisbonne et de Kew de 1896; de 

 S' Petersbourg (1873-85) et des jours dits normaux, et celle de Lisbonne de 

 1864-72, excepte les perturbations, d'apr^s la metbode du General Sabine. 



La S"""® Planche contient les variations diurnes du Bifilaire, du vertical et de 

 I'inclinaison a Lisbonne et Kew, 1894-95-96. 



' In fact, even the value of the Declination, one of the most important magnetic 

 elements, is given for one and the same place, Hoita in Fayal, with differences 

 amounting to 1° 22' in an interval of two years. Thus Preston in 1889 gives 25° 52' 

 and the Acor7i in 1891 gives 24° 30'. 



