1854.] Beport on the Dust Whirlwinds. 379 



of the air in these whirlwinds was more rapid on the side corre- 

 sponding to the onward track than on the opposite. 



On 5th July, about 6 a. m. a heavy fall of rain took place from 

 N. by E. attended at first by a good deal of wind. About 9 (a. m.) 

 the shower ceased, the thermometer outside the house (in the shade) 

 being then 78° E. During the remainder of the day, a pleasant 

 breeze continued from E. but without rain. 



It ought to be noted here that the prevailing descriptions of cloud 

 were electric cumuli ; which were chiefly in S. E. before the occur- 

 rence of the fall of rain. 



On the morning of 6th July, about 5 o'clock, a heavy fall of rain 

 took place with thunder and lightning, a particular note of this 

 shower was unfortunately not kept, but 2 8 inches of rain were 

 ascertained to have fallen in about 2-| hours, which was the time 

 during which it continued. 



After this the weather continued to become gradually less hazy, 

 and the sky less cloudy until the evening of the 10th when sunset 

 occurred with the ordinary clear weather which usually characterises 

 the hot season in the plains. 



Note. — Although no distinct " storm" is described in the obser- 

 vations that have just been made, I am nevertheless inclined to 

 hope that they will not be without interest in a meteorological point 

 of view, as being a record of the changes and appearances which 

 generally characterise the hot season. 



It will be observed that the number of " storms" of which I have 

 had it in my power to give even a general, and in some instances 

 very imperfect summary, is only twenty-one, and it must be con- 

 fessed that in more than one of these, the degree of atmospheric 

 perturbation was hardly of that degree which would fully justify the 

 appellation. 



Erom attention to the phenomema presented by even this small 

 number, however, a few interesting points, connected with them 

 may be said to be ascertained, and these may be divided into the 

 following heads. 



1st. The line of circular motion, tracks of storms, &c. 



2nd. Formation, and general phenomena of storms. 



The remarks under each head bearing reference only to these 



