1857.] Report on the Progress of the Magnetic Survey. 215 



perature of the ground are chiefly caused by jungles (in cooling it,) 

 or dry soils (in heating it.) The temperature of the surface of the 

 ground in the Punjab was never found to reach 40° it is therefore 

 considerably lower than in central India and the North-Western 

 Provinces, where I had often found 45° and even 50° Cent, as the 

 max. temperature of the surface. 



Coinciding with the lower temperature of the ground is the fact 

 that in the Punjab a thermometer with blackened bulb rises (put 

 on black wool,) but very little when exposed to the sun's rays, whilst 

 I saw it rising in Sind to 77°, in Leh in Ladak, elevation ll,800f., 

 it rose on the 8th July to 96° Cent. 8 degrees more than the boiliug 

 point of water at this height. 



Htdeogbaphical observations. 



Careful observations were made for ascertaining the discharge 

 of rivers, their temperature, the form and height of their banks, 

 etc. Observations of the breadth were made by long base lines 

 and triangulations. 



In order to make accurate observations on the depth and velocity 

 an anchor was used, which I carried with me for the purpose. 



The discharge was measured for the following rivers : — 



Jhelum at Pind Dadan Khan, Jhelum near Shapore, Chenab 

 near Jhuug, Bavi at Pasi Shah, Chenab at Mooltan, Sutlej or 

 Ghara at Bhawlpore, Indus at Sukkur, Iudus at Tatta and the dif- 

 ferent branches between Tatta and Sukput. 



In all these rivers a series of observations was made to ascertain 

 the mean velocity directly. 



Large (bamboo) sticks, weighed at one extremity with a bag con- 

 taining sand or stones, whilst a bladder was fastened to the upper 

 end to prevent their sinking, were floated vertically. 



The temperature of the Punjab rivers was surprisingly cold. 

 The banks of the Punjab rivers are exceedingly low, if compared 

 with those of the rivers in Hindostan proper, the Ganges, Jumna, 

 Nerbudda, Tonse, &c. 



I was enabled to collect, whilst travelling along the shores of the 

 Indus, many interesting data on the inundations of the Indus 

 in 1850. 



