TRANSACTIONS OF THE SECTIONS. 41 



the month of May, since the mean depression for the month at 4 p.m. was 31°"29» 

 the mean temperature at tiiat hour being 103°"35, which by Giaisher's factors would 

 give a dew-point of 56°'4, or nearly 47° below the temperature of the air. Apjohn's 

 formula would make the dew-point 53°'4, or 50° below the temperature of the air. 

 The mean temperature of 103°-35 at 4 p.m. in May far exceeds anything I ever ex- 

 perienced in India. The fall of dew was greatest in the first and fourth quarters of 

 the year, when the mean temperature is lower than during the other two quarters ; 

 but the greatest quantity of dew did not fall in the coldest months, with the excep- 

 tion of January. The evaporation was necessarily greatest in the hot quarter; but 

 somewhat singularly the next greatest amount was in the Monsoon quarter, when 

 nearly 20 inches of rain fell. 



Notice of Aurora Borealis seen al St. Ives, Hunts, Oct. 1 , 1 850. 

 By J. K. Watts. 



The phasnomena consisted of flashes, chiefly red, which often rose to the zenith. 

 There was no arch. The appearance lasted from 8 '55 to 9' 15. 



Notice of a Snoiv-Storm. By J. K. Watts. 



A remarkable thunder-storm, accompanied with snow, passed over the town of St. 

 Ives, Hunts, on Wednesday the 21st of August, 1850. For several previous days 

 the state of the weather had been unfavourable, with heavy rains and strong winds, 

 doing considerable damage to the corn crops in the neighbourhood, some of which 

 were entirely destroyed. On the morning of the storm, however, the sky remained 

 clear, a cold wind blowing directly from the north, until about 11 o'clock a.m., when 

 the wind, after shifting to and from all points, suddenly veered round to the south- 

 east, bringing masses of heavy cloud, apparently highly charged with electric fluid. 

 This state of the atmosphere continued till 1 o'clock p.m. ; cold rain falling at in- 

 tervals with three distinct currents of air, the upper and lower of them blowing from 

 the south-east with a great volume of dense rolling vapour, and the middle one from 

 the opposite direction, viz. the north-west, driving thin light cirro-cumulus clouds 

 before it with great rapidity. At about 2 o'clock a large black cloud approached the 

 town from the south-east, preceded by an extremely cold current of air. The ther- 

 mometer fell rapidly, and there was every sign of great atmospheric commotion. 

 When the storm approached the town, a large quantity of snow fell covering the roofs 

 of the buildings to some depth, and vivid discharges of electric fluid took place, with 

 deafening reports of thunder. This was followed by a driving shower of hail of large 

 dimensions, and a most piercing wind, the air being very oppressive as though 

 charged with sulphureous vapour. The wind then veered to the south, driving the 

 storm rapidly away towards the villages of Broughton and Ripton-Regis, where 

 pieces of ice fell of a large size, doing great injury to vegetation. 



When the storm had subsided one current of air only was perceptible, as the whole 

 body of vapour travelled in one direction towards the north-west. In the evening 

 the weather cleared up and the atmosphere became warmer. 



Account of a Lunar Rainbow, seen Aug. 23, 1850, between Haddenham and 

 Earith, near St. Ives. By J. K. Watts. 



The weather had been somewhat tempestuous for several days previously, with cold 

 rains and variable winds, and on the preceding night the moon was at the full. On 

 the night in question, the sky presented a most singular appearance : from the 

 horizon in the north-east across to the north-west, it was perfectly clear, the moon 

 and stars shining brilliantly ; while extending from the south-east to the north-west 

 and down to the horizon was one continuous mass of black cloud, so that one half 

 of the sky was quite light and cloudless, and the other half intensely dark. At 

 about 10 o'clock some small rain fell, evidently from the edge of the cloud above me, 

 and it was clearly perceptible that at a short distance from the spot where I was, it 

 rained heavily. Presently a broad and silvery-white arch appeared, being completely 

 semicircular ; and directly after, a second or outer bow, as perfect in every respect as 



