4'86 Notes, chiefly Geological, from Goott/ to Hydrabad. [May, 



friend's remarks, yet it cannot be denied that great and long conti- 

 nued pressure in general tends to consolidation. That it has not 

 produced this effect on the gravel of some of the deeper wells at 

 Hydrabad is, as Mr. Malcolmson observes, strictly the case, but 

 consolidation has been counteracted in a great measure, by the conti- 

 nual state of moistness in which the debris is kept by the percolation 

 of the spring water in its way upwards and the constant separation and 

 shifting of the particles by water in motion. The temperature of 

 a perennial spring of pure water in the garden of an Arab outside the 

 city walls, I found to be 80° Faht. Temp, of air in shade— 89°. 



The temperature of the Bhugga, whence many of the Mahomedan 

 nobles and the Minister Chundoo Lai procure water, was 79° 2'. Faht. 

 Temperature of air in shade 87°. 



The mean temperature of Hydrabad is I believe about 80°. — Height 

 above sea by boiling point of water 1 702 feet. 



On my way to Hydrabad, at Mahanundipet, about 42 miles north 

 of the Kistnah, date, June 4th, 1839, at 10° 15' a. m., I witnessed a 

 phenomenon rather rare in this part of India, viz. — an annular solar 

 rainbow. Its radius, taken to the inner circle from the sun's centre, 

 was 22° 30/ It continued advancing with the sun towards the zenith, 

 but disappeared gradually, before the meridian was attained, at an 

 attitude of about 75°. 



The sky was lightly veiled with thin grey clouds (cirri), amid which 

 the sun shone with a watery light, and defined disc, encircled by four 

 differently coloured, contiguous zones. The prismatic tint of the band 

 nearest the sun was orange, then yellow, pale green, and violet in suc- 

 cession. The united breadth of the four zones amounted to 38'. 



The wind was blowing strong and steadily from the west. The 

 thermometer in shade 80°. It had been on previous days usually 

 from 83° to 86° in the shade. At this time the temperature of the 

 open air was 86°. All the lunar halos in this country which I have 

 measured have a radius from 22° to 23° ; and there is, in general, a 

 slight depression in the thermometer at the time of their prevalence. 



