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  "text": "XVI. An Account of large subterraneous Caverns in the Chalk Hills near Norwich; by Mr. Wm. Arderon, F. R. S. comprised in a Letter from Mr. Henry Baker F. R. S. to the President.\n\nRead March 24, 1747-8.\n\nAs the Inspection and Study of Nature is the particular Province of the Royal Society, and every Attempt to improve our Knowledge is certain of your Favour, I take the Liberty to lay before you the Substance of a Letter from my industrious Correspondent and Friend Mr. William Arderon, F. R. S. containing the Description of a large Vault or Cavern, extended under several Hills near the City of Norwich, with some Observations and Experiments made by him there.\n\nAbout a Quarter of a Mile from the City of Norwich, on the East Side thereof, and near the Entrance of Moushold-Heath, is a large subterraneous Cavern, which has been formed in a long Series of Time, by the digging out of Chalk for the making of Lime. There's but one Entrance into it, whose Breadth is about two Yards, and its Height nearly the same; however the Height gradually rises, till at last it measures in some Places from twelve to fourteen Yards. But notwithstanding the Entrance is so small, the whole Area within is of such a large Extent, that twenty thousand Men might with great Ease be plac'd therein, as I believe will scarcely be doubted, when I assure you, that, from the Entrance to the furthest Part of these darksome Cells, measures full four hundred Yards; and that these Passages are frequently ten or twelve Yards wide, with Branchings out\nout on the Sides, into various Lanes and Labyrinth-\nkind of Windings, that every now and then open\ninto one another; which renders it no easy Task to\nfind the Way out, when a Person has been a little\nbewilder'd in these subterraneous Mazes.\n\nMost of these Vaults are arched at Top, whereby\nthe immense Weight, which every Moment presses\non them, is well supported; a Weight no less than\nthat of Hills, whose perpendicular Altitude above the\nTops of these Arches is twenty or thirty Yards, if\nnot much more. I have frequently, says my Corre-\nspondent, gone into these Caverns out of Curiosity;\nbut could never perceive the least Appearance of\nthose Damps* which are so common in Mines, and\nother subterraneous Places, where the Air is stagn-\nnant for want of a due Current; which shou'd seem\nto be the very Case here, as there is but one En-\ntrance into it. The Passage indeed is horizontal,\nand open to the West Wind; but the included Air's\nbeing free from Putrefaction, may possibly be owing\nto the large Quantity of Salt which the Chalk con-\ntains.\n\nHow deep or thick these Rocks of Chalk are, no\none, so far as I can find, can tell; for, in sinking\nthe lowest Wells, they have never, that I know of,\nbeen dug thro'; and consequently must be exceed-\ning deep. The Chalk at the further End of this\nCavern is so very soft, that it may be moulded with\nthe Hand like Paste; which I take to be its original\nConsistence, and what it always retains, till it be-\ncomes expos'd to the Air. In the very lowest Parts\n\n* Those are commonly caused by sulphurous Vapours, which\nnever appear in Chalk.\nof these Vaults I have pick'd up several Kinds of Fossils, figur'd by marine Bodies; such as *Echini*, *Pectunculi*, common or fluted Cockle, *Belemnitæ*, &c. and, by diligent Search, other Sorts might perhaps be found. Sounds made beneath these arched Roofs are strongly reflected from Side to Side; so that the least Whisper may be heard at a considerable Distance. The Beat of a Pocket-Watch was heard distinctly full twenty Yards from where it was plac'd.\n\nI visited this Place on the 1st Day of November last, in order to try the Temperature therein, as to Heat and Cold; and carried with me a Thermometer regulated by one of Mr. Hauksbee's, which I set down at the further End of these Caverns; and letting it remain there for some time, I found the Mercury rested at $52^\\circ$. which comparing with the Register I had kept, was, I found, within half a Degree of a Medium betwixt the greatest Heat and the sharpest Cold we have known in this City for ten Years past; and it is very probable, if the two Extremes had been taken more exactly, the Temperature in these Caverns would be found to come yet nearer to the Medium of Heat and Cold in this Climate.\n\n**Hauksbee's Therm.**\n\n| Greatest Degree of Heat | July 18. 1746. | 15 |\n|-------------------------|---------------|----|\n| Greatest Degree of Cold  | Jan. 9. 1740. | 88 |\n\nWhich added together make ——— ——— 103\n\nThe Medium of which is ——— ——— 51½\n\nI find,\nI find, by inspecting Mr. George Martin's Collection, and Comparison of the Scales and Degrees of Heat with various Thermometers, that the Temperature of Heat in these Caverns coincides with that in the Cave at the Observatory at Paris, within one Degree; which I think comes very near, considering the Observations were made with different Instruments, and formed upon different Principles.\n\nAt the Foot of a high Hill, adjacent to these Vaults, issues out a curious Spring, whose Water I found exactly of the same Temperature with that underground; though, when the Thermometer was exposed to the open Air, it stood at $57^\\circ$.\n\nPermit me, Sir, to subscribe myself, with the utmost Truth and Respect,\n\nLondon, March 15,\n1747-8.\n\nYour most obedient\nhumble Servant,\n\nHenry Baker.\n\nA terrible Thunder-Storm, June 12, 1748, shook the Earth to such a Degree as to throw down those Chalk-Vaults.",
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    "title": "An Account of Large Subterraneous Caverns in the Chalk Hills Near Norwich; By Mr. Wm. Arderon, F. R. S. Comprised in a Letter from Mr. Henry Baker F. R. S. to the President",
    "authors": "Henry Baker",
    "year": 1748,
    "volume": "45",
    "journal": "Philosophical Transactions (1683-1775)",
    "page_count": 5,
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