VOL. XIII.] PHILOSOPHICAL TRANSACTIONS. 553 



wanted only some courage to find out the bottom of it. The captain resolved 

 to adventure, and on the 18th and igth of Sep. l682, he took several of his 

 men, with ropes and tackling fitting to descend, with lines to measure any 

 length or depth, also with candles, torches, and a speaking trumpet. What 

 he found does much lessen the credit and terror of this hole, as will appear by 

 the figure he took thereof, and the description following : 



** It is down the tunnel from the superficies to the opening of the cavity be- 

 low 39 yards. Then the hole spreading into an irregular oblong figure, is in 

 the greatest length 75 yards, and in the greatest breadth 41 yards; from the 

 highest part of the roof to the water was then 19 yards; the water was now in 

 a pool, at the north end, being the deepest part, it was in length 27 yards, in 

 breadth 12, and only 5 yards and ^ deep; two rocks appeared above the water 

 all covered with mud, but the water sweet and good ; there was a large circle 

 of mud round the pool, and far up towards the south end, which showed that 

 the water has at other times been 6 yards higher than at present. 



" The tunnel or passage down was somewhat oblique, very ragged and 

 rocky ; in some places it was 2 yards wide, and in some 3 or 4, but nothing ob- 

 servable therein, save here and there some of that spar which usually attends 

 the mines of lead ore. In the way, 30 yards down, there runs in, southward, 

 a passage of 29 yards in length, parallel to the superficies above; it was 2 and 

 3 yards high, and commonly as broad, and alike rocky as the tunnel, with some 

 appearances of spar, but nothing else in it except a few bats. 



" The cavity below was in like manner rocky, and very irregular ; the can- 

 dles and torches burnt clear, so as to discover the whole extent thereof; nor 

 was the air any thing offensive. The 3 men that went down the first day staid 

 below 2 hours and i. The next day the captain went down with 7 or 8 men, 

 who staid below for an hour, and observed all things. 



*' The bottom of this hole, where the land- waters gather, is 59 yards down 

 from the superficies of the earth, and by good calculation the same bottom is 

 20 yards above the highest rising of the Severn, and lies into the land about 3 

 miles distant from it." 



The profile and ground-plot of the concave in Pen-park, before described, 

 fig. 1, pi. 16. — A is the superficies of the earth; B the lead-ore pit; C the 

 tunnel or passage down; D the long gallery; E the concave or cell; F the 

 upper edge of the mud; G two small rocks that appear above the water; H the 

 upper part of the water; I the bottom of the water; K the highest mark of 

 the water; L two rocks. 



VOL. II. 4 B 



