25*2 PHILOSOPHICAL TRANSACTIONS. [anNO I716. 



has a limit; for if n be equal to ^in, the point v will fall on b; and the whole 

 disk of a planet at that distance from the sun would be the maximum, viz. when 

 in its superior conjunction with the sun. And the like if n were less than ^m; 

 the arch gv in such case not intersecting the semicircle be. 



jin Account of a very uncommon sinking of the Earth near Folkestone in Kent, 

 In a Letter from the Rev. Mr. John Sackette, A. M. to Dr. Brook Taylor, 

 R. S. Seer. N° 349, p. 469. 



Concerning the pressing forward of the cliffs, and sinking of the hills in the 

 neighbourhood of our town of Folkestone; fig. 5, pi. 5, represents a sketch of 

 the situation of the country, showing a straight road from what is called the 

 Mooring Rock to Tarlingham House; the manner of the country, as to the 

 rising and falling, being much the same, for about a mile on either hand of the 

 road described. 



a represents the Mooring Rock, about halfway between high and low water 

 mark ; b the foot of the cliff, 50 yards from the rock ; c the top of the cliff, 

 about 6 yards high; cd a plain of 50 yards; de a cragged cliff, of 6o yards 

 high; EP a plain above a mile long; fg a hill of steep ascent, near half a mile; 

 GH the land from the top of the hill to the house, near a mile; i Tarlingham 

 House, lying near 24- miles, N. N. W. from the rock; egh a line of sight; kbl 

 the shore at high water mark. 



The Mooring Rock, though surrounded with many others, is a very noted 

 one, and has immemorially borne this name, as vessels are usually moored here, 

 while they are loading with the other rocks. It has remained fixed thus beyond 

 the memory of man, and old men have observed, that for 40 years and upwards, 

 the distance between it and the foot of the lesser cliff ab, has been much the 

 same; this creates great surprise: for they can prove by good marks, that the 

 lesser cliff bc has been constantly falling in; insomuch that from time to time, 

 in their memory, near 10 rods forward to the land has been carried away by the 

 sea. From whence, as it appears that the plain between the top of the lesser 

 cliff and the foot of the higher cd, has been formerly double the breadth that 

 it is at present, so the distance between the rock and the foot of the lesser or 

 lower cliff ab, should have increased in proportion, and would have been double 

 at present to what it has been formerly ; but this distance remaining the same, 

 or rather less, as several think, is very surprising; nor can it be accounted for 

 otherwise, than by supposing that the land pressing forward into the sea is 

 washed away by the high tides, and as often as this happens, it presses forward 

 again. This pressing forward of the land into the sea would be incredible, were 

 it not shown to be matter of fact; and that not only at this one place of obser- 



