xllV NOTES. 



Asia, as quite unconnected with the line of no declination of Australia, the Indian 

 Sea, Western Asia, and Lapland. 



( 193 ) p. 149. I have spoken elsewhere (Asie Centrale, t. iii. p. 458 461) 

 of this identity, founded on my own observations of the declination on the Cas- 

 pian, at Uralsk on the Jaik River, and in the steppe near Lake Elton. 



( 194 ) p. 149. Adolf Erman's Map of the Magnetic Declination, 1827 1830. 

 Elliot's Map shows decidedly that the Australian line of no declination does not 

 traverse Java, but runs parallel to the south coast of that island, at a distance of 

 a degree and a half of latitude to the south of it. According to Erman (not 

 according to Gauss), the Australian line of no declination passes between Ma- 

 lacca and Borneo, through the Sea of Japan, to the closed oval group of Eastern 

 Asia, entering the continent at the north shore of Ochotsk (in lat. 59^), and 

 yet redescends through Malacca, so that the ascending and descending portions of 

 the line are there only eleven degrees apart; and in this representation the west 

 Asiatic line of no declination (from the Caspian to Russian Lapland) is an im- 

 mediate continuation of the portion which comes down from north to south. 



( 195 ) p. 150. In 1843, in my Asie Centrale (t. iii. p. 469476), I remarked, 

 from documents preserved in the archives at Moscow and at Hanover, that Leib- 

 nitz (who had proposed the first plan for a French expedition to Egypt) had 

 also been the first who had sought, by availing himself of the relations established 

 in Germany, in 1712, with Czar Peter the Great, to get the position of the lines 

 of declination and inclination determined throughout the Russian Empire an 

 extent exceeding that part of the moon's surface which is seen from the Earth 

 and to arrange that this determination should be repeated at given epochs. In 

 a letter written to the Czar, which Pertz has discovered, Leibnitz refers to a 

 small hand-globe (terrella), still preserved at Hanover, on which he had drawn 

 the curve for which the declination is 0, his " linea magnetica primaria." He 

 maintained that there is only one line of no declination, dividing the globe into 

 two nearly equal parts, having four " puncta flexus contrarii," or sinuosities, 

 running from Cape de Verde towards the American coast in 36, and then 

 directing itself through the Pacific towards the east of Asia and New Holland. 

 He made this line pass not through the poles of the Earth, but nearer to the 

 South Pole, where he supposed the declination to be 5, than to the North, where 

 he supposed it to be 25. He further considered the movement of this important 

 curve to be, in the beginning of the 18th century, towards the north ; and east 

 declination, from to 15, to prevail over great part of the Atlantic, through- 

 out the Pacific, in Japan, and in part of China and of New Holland. He pro- 

 posed that, the surgeon Donelli being dead, he should be succeeded by another. 

 " who might give few medicines but many good scientific counsels for making the 



