60 Formation and Dispersion of a Tliunder Showef. 



cloud, and a visible prolongation and . elevation of the cirri was 

 taking place. In a short time rain could be discovered precipita-. 

 ted from the cloud, and the roaring noise continued without in- 

 terruption, exhibiting a singular contrast to the quiet and immo- 

 vable state of the cloud. At this time the cloud was about three 

 miles distant, and the angle of elevation shows its height to have 

 been about six hundred feet. 



The general movement of the cloud, it was soon apparent, was 

 to the N. W., and in about twenty minutes after the first indica- 

 tions of a shower, I was driven within doors by a fall of the larg- 

 est drops of rain I think I have ever seen. They were not nu- 

 merous, but in falling seemed as large as cherries, and dashed 

 upon the earth with the seeming force of a hailstone. No hail 

 was observed by me, but the size of the drops excited general no- 

 tice. A heavy shower of perhaps ten minutes followed these 

 drops, but during the whole, though the roaring noise continued 

 unabated, not the shghtest wind in any direction could be felt, 

 but the water poured down perpendicularly like a cataract. This 

 was particularly observable when the shower had passed so that 

 the line of fall was about one hundred rods to the west of us. 

 While it was a blue sky over head, at that distance from us for 

 ten minutes the water was pouring down in a vast sheet, and one 

 mile west of us more water fell than during any other shower of 

 the season. Before the shower had become perpendicular to us, 

 or perhaps twenty minutes after the first rain fell from the cloud, 

 thunder was heard in it ; and after it passed, several electric ex- 

 plosions occurred. About five miles to the N. W, it ceased to 

 rain, and the cloud rapidly melted away ; and in two hours from 

 its commencement nothing was to be seen of it except the train 

 of cirri, resembling a streak of white smoke high up the sky. 



But the most singular part of this electric shower remains to be 

 noticed. During the time of its passage, on the eastern margin 

 of the cloud, about two miles northeast of us, little rain fell, but 

 hail and snow were both precipitated from the atmosphere. On 

 the west side of the cloud the thermometer was but little af- 

 fected, not more than is usually the case in summer showers ; on 

 the eastern or northeastern side, the cold was perceptible, and the 

 thermometer fell rapidly ; but in neither case was there any appa- 

 rent atmospheric movement to account for such a change. I may 

 remark here, that while the cloud remained stationary just west 



