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

by William Allen and Samuel Woods

XIX. Barometrical Measurements.

By WILLIAM ALLEN, F.R.S

member of the geological society.

[Read 19th November, 1812.]

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.		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

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XIX. Barometrical Measurements.

By SAMUEL WOODS, Esq.

member of the geological society.

[Read 19th November, 1812.]

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