# Transactions of the Geological Society, 1st series, vol. 4/Barometrical Measurements

XIX. Barometrical Measurements.
By WILLIAM ALLEN, F.R.S
member of the geological society.
The following measurements were made with a single Barometer of the construction proposed by Sir Henry Englefield, and have been calculated according to the formula recommended by him in his memoir on the subject, which is inserted in the 14th volume of Nicholson's Journal. I shall give in detail the observations made upon Snowdon; and of the other measurements I shall mention only the results.
Snowdon. :
| Observ. | Observ. | Hour | Hour | September 8th, 1806 | Therm. | Barom. |
| 1 | A.M. | 9 | 00 | Goat Inn, Beddgelert | 61 | 29.69 |
| 2 | —— | 10 | 25 | Llyn Cader | 61 | 29.162 |
| 3 | P.M. | 1 | 25 | Summit of Snowdon | 50 | 26.164 |
| 4 | —— | 4 | 00 | Llyn Cwellyn | 56 | 29.30 |
| 5 | —— | 4 | 45 | Llyn Cader | 57 | 29.12 |
| 6 | —— | 6 | 00 | High water-mark at Pont-aber-glas-Llyn | 55 | 29.78 |
| 7 | —— | 6 | 30 | Goat Inn at Beddgelert | 53 | 29.6 |
It appears from observations 1 & 7 that the Barometer had fallen at Beddgelert in 9$\scriptstyle {\frac {1}{2}}$ hours 0.09 inches, and from observations 2 & 5 that it had fallen at Llyn Cader in 6$\scriptstyle {\frac {1}{4}}$ hours 0.042 inches. The descent of the mercury may therefore be estimated at about 0.008 inches an hour, for which due correction has been made in each observation on calculating the measurements. ​
| | Feet. |
| From Observations 6 and 7, the height of Beddgelert Inn above high water-mark | = 162.7 |
| From Observations 1 & 4, the height of Llyn Cwellyn above Beddgelert | = 314.2 |
| above the Sea | = 476.9 |
| | From Obs. 1 & 2 | From Obs. 1 & 3 | mean |
| The height of Llyn Cader above Beddgelert | 489.3 | 480.2 | 484.7 |
| above the Sea | 652. | 642.9 | 647.4 |
| | From Obs. 1 & 3 | From Obs. 3 & 7 | mean |
| The height of Snowdon above Beddgelert | 3457.5 | 3409. | 3433.2 |
| above the Sea | 3620.2 | 3571.7 | 3595.9 |
In the following measurements only one observation was made at the lower station, unless the contrary is stated.
Cader Idris. :
| The height of the highest Peak above Dollgellau | 2879 |
| The height of the highest of the three Heads above Dollgellau | 2840 |
| Ingleborough ||
| The height of Ingleborough above the Bay-horse Inn, Ingleton | 1881 |
| Ingleton is 90 feet below Settle; the height of Settle has been accurately taken, and is stated at 621 above the sea; therefore the height of Ingleton above the sea is | 531 |
| and the height of Ingleborough above the sea is | 2412 |
| Whernside ||
| The height of Whernside above Ingleton | 1930 |
| above the sea | 2461 |
| Pen-y gant. ||
| The height of Pen-y gant above Settle | 1858 |
| above the sea | 2479 |
| Shap Fells. ||
| The height of the highest point in the road between Kendal and Shap above Kendal | 1187 ​ |
| Helvellyn. ||
| From two observations made the same day at Paterdale.—Day rainy.-The Barometer varied .194 in 5 hours.—The Inn at Paterdale is 24 feet above Ullswater. |
| The height of Grisdale brow above Ullswater | 988 |
| ──── of RedTarn | 1935 |
| ──── of the top of Helvellyn | 2686 |
| Saddleback. ||
| Threlkeld, where the first observation was made, is 235 feet above the level of Keswick Lake, which is 228 feet above the sea. |
| above Keswick Lake. above the Sea The height of Saddleback—the Pummel 2615 2843 the Crupper 2561 2789 ||
| Skiddaw. ||
| The Oak Inn at Keswick, where the first observation was made, is 28 feet above the lake, which is 228 feet above the sea. |
| above Keswick Lake. above the Sea The height of Latrigg 330 558 of Half-way stone 1408 1636 of the summit of Skiddaw 2789 3017 ||
XIX. Barometrical Measurements.
By SAMUEL WOODS, Esq.
member of the geological society.
In the following measurements only one observation was made at the lower station, unless the contrary is stated. They are calculated according to the formula of Sir Henry Englefield.
| Branch of the Mendip hills just above and eastward of Cross; the point appears to the eye to be one of the highest in the Mendip range. Height above Cross | 670 ​ |
| Helvellyn. ||
| Height above the sea ||
| Feet ||
| Dunkerry Beacon, one of the highest points of Exmoor, near Minehead. Weather cloudy, with light rains. From two observations, one at Porlock Quay, the other at Minehead Quay, the Barometer had fallen 0.14 inches in 5 hours | 1784 |
| Top of Brendon hills in the road between Minehead and Dulverton | 1210 |
| North hill above Minehead | 1000 |
| Highest point in the road between Barnstaple and Ilfracomhe | 900 |
| Linton Church-yard, in the North of Devonshire | 428 |
| Exmoor, about 4 miles south of Linton; one of the highest points on the Devonshire side of Exmoor | 1608 |
| Hill called Hangman, near Comb-Martin | 1093 |
| Hill about 1 mile east of the Hangman | 1168 |
| Yester, near Okehampton, one of the highest points of Dartmoor, above the Inn at Okehampton, 1561 feet | 2077 |
| The height of the Inn at Okehampton | 516 |
| Hastings, Sussex. ||
| General Roy's station near the Windmill on Fairlight Common | 588 |
| East Cliff | 190 |
| Hill above the East Cliff | 313 |
| Castle Hill | 180 |
| Castle Cliff | 135 |
| Dover. ||
| Western height | 382 |
| Shakespear's Cliff | 310 |
| Summit of Castle-hill, beyond the turnpike | 390 |
| Dorking, Surry. ||
| Heights above the bed of the Mole. ||
| Feet ||
| Box-hill about | 300 |
| Headley Church, and the highest part of the wood on Mickleham Downs | 466 |
| Norbury park | 292 |
| Bench beyond the summit of the park | 320 |
| Leith hill tower | 803 |
| Beech Trees on the south side of Headley Common | 585 |