360 Report on the Dust Whirlwinds. [No. 4. 



in the former direction. A few drops of rain fell at 7.30 (of 6th) 

 the wind at that time being S. W. Towards morning the violence 

 of the thunder increased and a storm of wind and rain was audible* 

 The early part of the 7th was still cloudy, occasional puffs of dust 

 swept past, — and in various directions revolving pillars of sand indi- 

 cated the presence of whirlwinds of small size at different parts of 

 the surrounding plain. 



The wind at 9 a. m. of the 7th was N. by E. and at noon E. by S. 

 having gradually veered to that point by N. E. About 2 p. m. the 

 sky at S. E. was very hazy as if portending rain and wind. A small 

 cyclone soon afterwards made its appearance and passed over our 

 house, taking a direction in its onward course or track of N. E., the 

 wind at the same time blowing from S. E. As the body of the storm 

 advanced from the station, it was seen first to curve gently to W. 

 but in a few minutes appeared to be broken up. The wind during 

 the remainder of the evening continued at S. E. the atmosphere 

 was clear, — and several slight squalls continued to come on at 

 intervals. 



This storm appears to be interesting on account of the meteorolo- 

 gical appearances that accompanied it. From the position of its 

 body as compared with the wind point, it appears evident that 



a. The circular current of air was from L. to E. or with the 

 hands of a watch. 



6. — \2th March, 1853. Since the occurrence of the storm just 

 described the sky had continued dull and cloudy, presenting all the 

 indications of approaching rain. During the day (of the 12th) there 

 were occasional gusts of wind from various and uncertain directions, 

 at the same time that there was more fine sand floating through the 

 atmosphere than could be well accounted for by the slight breezes 

 that prevailed. It was difficult to say what part of the sky pre- 

 sented the most threateniug appearance, and towards evening this 

 increased. About 6, 30 p. m. rain began to fall ; the shower com- 

 ing from about S. W. and about 10 to 11 p. m. rain was falling 

 in torrents. 



The greater part of this storm having occurred at night, no notes 

 were taken from which to trace the shifting of the wind. 



Imperfect as the description of this storm is and although not 



