* Heave the vast spars. l. 116. Water in descending down elevated situations if the outlet for it below is not sufficient for its emission acts with a force equal to the height of the column, as is seen in an experimental machine called the philosophical bellows, in which a few pints of water are made to raise many hundred pounds. To this cause is to be ascribed many large promontories of ice being occasionally thrown down from the glaciers; rocks have likewise been thrown from the sides of mountains by the same cause, and large portions of earth have been removed many hundred yards from their situations at the foot of mountains. On inspecting the locomotion of about thirty acres of earth with a small house near Bilder's Bridge in Shropshire, about twenty years ago, from the foot of a mountain towards the river, I well remember it bore all the marks of having been thus lifted up, pushed away, and as it were crumpled into ridges, by a column of water contained in the mountain.
From water being thus confined in high columns between the strata of mountainous countries it has often happened that when wells or perforations have been made into the earth, that springs have arisen much above the surface of the new well. When the new bridge was building at Dublin Mr. G. Semple found a spring in the bed of the river where he meant to lay the foundation of a pierre, which, by fixing iron pipes into it, he raised many feet. Treatise on Building in Water, by G. Semple. From having observed a valley north-west of St. Alkmond's well near Derby, at the head of which that spring of water once probably existed, and by its current formed the valley, (but which in after times found its way out in its present situation,) I suspect that St. Alkmond's well might by building round it be raised high enough to supply many streets in Derby with spring-water which are now only supplied with river-water. See an account of an artificial spring of water, Phil. Trans. Vol. LXXV. p. 1.
In making a well at Sheerness the water rose 300 feet above its source in the well. Phil. Trans. Vol. LXXIV. And at Hartford in Connecticut there is a well which was dug seventy feet deep before water was found, then in boring an augur-hole through a rock the water rose so fast as to make it difficult to keep it dry by pumps till they could blow the hole larger by gunpowder, which was no sooner accomplished than it filled and run over, and has been a brook for near a century. Travels through America. Lond. 1789. Lane.
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