cxlviii NOTES. 



distant from the Himalaya. The brothers Hermann and Robert Schlagintweit 

 were the first who, in the months of July to September 1856, succeeded in the 

 adventurous attempt of proceeding frcm Ladak across the range of the Kuen- 

 lun, and reaching the territory of Khotan. According to these always careful 

 observers, the strike of the highest water-dividing range at the northern boun- 

 dary of Thibet, and on which the Karakorum Pass, 18,300 feet high, is situated, 

 is S.E. N.W., therefore parallel to the portion of the Himalaya, which is over 

 against it (. e. that to the west of Dhawalagiri). The rivers of Yarkand and 

 Karakasch, which form part of the great water-system of the Tarim and Lake 

 Lop, take their rise on the north-eastern declivity of the Karakorum chain. 

 From the area of this system of waters, the travellers passed over Kissilkorum, 

 and by the Hot Springs (49 cent., 110 0< 2 Fahrenheit), to the little Alpine 

 lake of Kiuk-kiul in the east and west Kuen-lun range. (Report of Mag. Sur- 

 vey, No. VIII. Agra, 1857, p. 6.) 



( 57S ) p. 418. Kosmos, Bd. i. S. 27, 48, 181; Bd. iv. S. 3447, 164 

 169, and 369, mit Anm. 39 and 40 (English edition, vol. i. p. 27, 46, 131; 

 present volume, Notes 33 47, 463, and 464). 



( 574 ) p. 418. Arago (Astron. populaire, t. iii. p. 248) assumes almost the 

 same thickness for the crust of the earth : 40,000 metres, about 5^ German 

 geogr. miles, or 22 English; Elie de Beaumont (Systemes de Montagnes, t. iii. 

 p. 1237) makes the thickness one fourth greater. The earliest-made assumption 

 was that of Cordier, in mean value 14 German or 56 English geographical miles: 

 Hopkins's Mathematical Theory of Stability would require it to fall between 

 688 and 860 English geographical miles. On geological grounds, I fully con- 

 cur with Naumann's doubts of so enormous a distance between the fluid in- 

 terior and the craters of active volcanoes. See his excellent Lehrbuch der 

 Geognosie, Bd. i. S. 62 -64, 7376, and 289. 



( 575 ) p. 419. A very remarkable example of the manner in which appre- 

 ciable alterations of composition may take place, through the gradual accumu- 

 lation of very minute quantities, has been recently presented by Malagute's 

 discovery, confirmed by Field, of the presence of silver in sea-water. Notwith- 

 standing the enormous extent of the ocean, and the small surface of the hulls of 

 the ships which traverse it, the trace of the silver in the sea-water has become 

 perceptible on the copper-sheathing of vessels. 



( 576 ) p. 420. Bunsen, Ueber die chemischen Prozesse der vulkanischeu 

 Gesteinsbildungen, Poggend. Annalen, Bd. Ixxxiii. S. 242 and 246. 



( 577 ) p. 420. Comptes rendus de 1'Acad. des Sciences, t. xliii. 1856, p. 366 

 arid 689. The first exact analysis of the gas which issues forth with noise 

 from the great Solfatara of Pozzuoli, and which was collected with much difil- 



