578 TRANSACTIONS OF THE 



vation of lands; for instance, at a mean height of 3,900 metres 

 (nearly 14,000 feet) in September, as an approximate medium of 

 the year, the temperature varies at 9 o'clock A. M. from 14 to 16 

 degrees (centigrade probably), equal to Fahrenheit 5 7 to 62 degrees. 

 In winter the dryness is somewhat less. In this region the fine 

 wool goat (duvet normal) is found at an elevation of from 2,500 

 to 3,000 metres (from about 8,000 to 13,000 feet). The diminu- 

 tion of temperature of one degree, centigrade, coiresponds with 

 a difference of height of 180 or 190 metres (570 to 580 feet), the 

 variation of moisture l>eing small. 



The yaks of the pure breed, which are not like the dehoubous> 

 crossed with the zebu of the Indies, go on these mountains as 

 high as nearly 18,000 feet. The yak is one of the animal king- 

 dom most acclimated to cold, and to verj low atmospheric pres- 

 sure. The yaks of pure blood descend during winter to about 

 5,000 feet elevation, in the Bantlin, for a few weeks only. They 

 cannot exist in the humid parts of the Himalaya mountains. Ex- 

 periments with them have been made at Simla, Dant, Jiliug, &c., 

 and failed. The drought of the region of the wild yaks is ex- 

 treme, much greater than that of the fine wool goat. The dehou- 

 bous always cross well with yaks and buffalos or zebus, which 

 live in the w^armest regions, but sufier when the humidity is 

 greater than it is in the temperate parts of France. 



Note. — The existence of the yak (or Thibet ox), as wild, has 

 been often doubted, but we have frequently found them wild, 

 chiefly on those slopes of mountain chains which separate the 

 Indus of Sutleges, near the sources of the Indus and the environs 

 of the Gastok, but the greater numbers are found at the foot of 

 the northern slope of the chain of Karkoram, as well as in the 

 south of Kuenluen in Turkistan, in western Thibet, pjirticularly 

 in the Hadak. The true yak can hardly exist at 8,000 feet ele- 

 vation in summer. We have found large herds of them at over 

 18,000 feet elevation, and we have found some as high as 19,500 

 feet, far above the limits of vegetation, and more than 1,000 feet 

 above that of the snow. 



The hybrid of yak with the Indian cow is called choobou. It 

 is remarkable that these are most useful to the people of the 

 Himalaya mountains. 



