TRANSACTIONS OF SECTION E. 547 
The whole of the office work was carried out by Dr. Bruce and Mr. Mathieson, 
who accompanied Dr. Bruce in the field during the summer of 1909, while com- 
pleting the survey of the southern extremity of the Foreland. 
Mr. Mathieson was able to cross his work with that of Dr. Bruce, and the 
result has been highly satisfactory, in that the observations of the one surveyor 
have been checked by those of the other. 
Besides the topographical survey of the Foreland, Dr. Bruce was able to 
take a number of soundings in Foreland Sound. 
Owing to the inaccessibility of most of the mountain peaks the method adopted 
for the survey was to measure two base lines—one at the north end 12,000 feet, 
and another across the flat land at the south end 20,146 feet. These were 
measured by a Chesterman steel tape, and from their extremities a network of 
triangles was spread over the whole island. More than eighty summits were 
observed. 
The coast line was surveyed by a measured traverse, which was connected 
with the triangulation at every available point. Fjords at the south end pre- 
sented difficulties, where measurements had to be taken by the subtense method, 
and also along the 20 miles of crevassed glaciers on the east side, where trigono- 
metrical points were fixed at suitable intervals, as actual measurements were 
out of the question. 
Additional observations were also made from the mainland at three important 
stations in order to bring the Foreland into satisfactory relationship with the 
mainland. 
The heights and horizontal angles were observed by 6-inch theodolites, and 
nearly all the altitudes were observed from at least two independent points. 
The Devil’s Thumb was observed from more than fifteen points, and heights 
obtained varying from 2,590 feet to 2,610 feet, giving a mean of 2,602 feet. 
Similarly, Saddle Mount was observed from over twenty stations, and the heights 
obtained varied from 1,400 feet to 1,410 feet, giving a mean of 1,406 feet. This 
mountain was stated by early explorers to be 600 feet, but later it rose to 
800 feet, then to 1,000 feet, and, latterly, to 1,200 feet. 
The magnetic variation was 14° 40’ in 1909, and the dip 73° 23’. The latitude 
was observed in five different places, many observations being taken at most of 
the places. 
The area of the island is about two hundred and fifty square miles, half of 
which is below the 100-feet contour, and one-fifth of which is covered by glaciers. 
The remainder consists of high mountain peaks and huge moraines. 
2. Gaping Ghyll, Yorkshire: Its Exploration and Survey. 
By ©. A. Hi, M.A., M.B. 
Gaping Ghyli, the best known of the Yorkshire pot-holes, is situated on the 
south-eastern flank of Ingleborough, the opening being about 1,350 feet 
above O.D. It consists of a vertical shaft in the limestone, 360 feet in depth, 
ending in a huge chamber from which passages extend for a distance of upwards 
of a mile. A stream, the Fell Beck, is engulfed in this chasm and reappears 
at Beck Head at a slightly lower level than the entrance to the famous Clapham 
Cave. 
The first mention of Gaping Ghyll is found in Defoe’s ‘Tour of England,’ * 
where it is called Gaper Gill. <A partial descent of the hole was made in 1872 
by Mr. Birkbeck, of Settle, who then ascertained its true depth. The first 
complete descent was achieved by M. Martel, of Paris, in August 1895, by means 
of rope ladders.” 
In May 1896 the members of the Yorkshire Ramblers’ Club made the second 
descent by means of a boatswain’s chair lowered from a windlass. About a 
quarter of a mile of passages was surveyed on this occasion, and a plan and 
section afterwards published in the Club Journal.® 
? Seventh edition. 1769, vol. iii., p. 293, 
* Martel, Zrlande et Cavernes Anglaises, 1897, chap. xxiv. 
* Y.R.C. Journal, No. 2, Jan. 1900. 
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