l6 PHILOSOPHICAL TRANSACTIONS. [aNNO 1 755. 



minus electricity of the Leyden experiment only, which that gentleman dis- 

 covered. 



evil. On the Extraordinary Agitation of the Waters in Several Ponds in Hert' 

 fordshire. By the Rev. Thomas Rutherjortk, D.D., F. R. S. p. 684. 

 On the 1st. of Nov. last (1755) there was an unusual motion of the water in a 

 pond at Patmer-hall, a farm in the parish of Albury, and county of Hertford. 

 Mr. Thomas Mott, the occupier of the farm, stated that there are two ponds in 

 his yard, parted from each other by a causey, just wide enough to allow of a 

 convenient passage for a waggon and driver : the causey runs from north to 

 south ; so that one of the ponds is to the west, and the other to the east of it. 

 At the western end of the former are 1 drains, one higher than the other, to 

 carry off the waste water ; and on each side, at the other end, close to the cause- 

 way, is a mouth, or opening, where his cattle go to drink. The pond itself is 

 about 8 roods over, and 1 2 roods long. The other pond is of the same size ; 

 except that there is a dove-house in the middle of it, which stands on a small 

 island. On the first day of Nov. last, between 10 and 11 o'clock in the fore- 

 noon, his servants, who were then close to these ponds, heard a rumbling noise 

 like the wind ; and 3 ducks, which were then in the western pond, immediately 

 flew out of it into the other, as if they were frightened. At the same instant the 

 water in the western pond rose at the head of it, so as to run out of the lower 

 drain, which was 10 or 12 inches above the level. It continued to move back- 

 ward and forward for some time ; but it did not swell any more at the head, but 

 only rose and fell by turns at the two mouths ; so that the motion was then from 

 north to south. When it rose at either of the mouths, it flowed about 6 feet 

 beyond what was then the water-mark. The other pond was quite still during 

 the whole time. 



Mr. Mott further stated, that at Wickham-hall, another farm about two 

 miles and a half from him, in the parish of Bishop-Stortford, in the same county, 

 a pond was moved at the same time in the same manner ; and that the first 

 motion of it was from east to west. And that a like motion was observed in a 

 pond at Thaxted, in the county of Essex. At Royston also, in the county of 

 Hertford, an unusual motion was observed in the pond, at 10 o'clock in the 

 forenoon, Nov. 1, last past. The pond is a large one, and almost round. The 

 bank of it, towards the north, is faced with a brick wall ; and the bottom rises 

 in a slope towards the south, so as to go 5-J- feet beyond the water-mark. In 

 its return it rose against the brick wall, the top of which was about one foot 

 above the level of the water, so as to run over it. The water afterwards moved 

 from north to south, and back again, 5 times before it stopped. 



