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This is intended to difplace the damp air or gas, but is not 

 very efficacious, becaufe the damp air is of a greater fpe- 

 cific gravity than pure air ; fo that ten gallons of frefti air 

 is perhaps blown into the well, before two gallons of 

 noxious air is difplaced : and this probably happens be- 

 caufe the atmofpheric air is fpecifically lighter than the 

 noxious air, and afcends through the latter to the top of the 

 well, difplacing but a fniall quantity of it. Such bel- 

 lows, &c. are feldoni to be procured on the fpot when 

 wanted, and are too weighty and cumberfome to carry about. 

 If water is thrown down in a Ihower, it will fometimes clear 

 the air ; but this is laborious, in a deep well, to draw it up 

 again. 



The following appaiatus may be ufed with great fuccefs 

 in fuch cafes ; and as with ^fty^ feet of pipe its weight 

 amounts only to thirty pounds, it may eafily be carried to 

 any diftance. Tubes of every kind being perpendicularly 

 fituated, and having their internal air rarefied, caufe a cur- 

 rent or ilream of air to afcend through them. Suppofe fix 

 lengths of metal pipe, each eight feet long, and two inches 

 diameter, all made of tin plate, except the upper one, which 

 is of copper, the better to bear the heat ; let a cylindrical 

 vefTel be alfo made of copper, holding about two gallons, 

 fixed fall to the upper pipe, and having tlu-ough the fides of 

 it a number of holes to admit air for the fupport of the fire, 

 which is kindled within it. The veflel muft be fo fixed as 

 to have at leaft five feet of pipe above its top. 



The method of placing it in the well is, firft, to lower 

 down the bottom length, into the upper end of which, the 

 lower end of the fecond length is joined, paffing a wire 

 through both to prevent their drawing apart again in holes 

 made for that purpofe ; then fill the joint round with oil- 

 putty, fo as to render it air-tight. The upper end of each 

 length of tube is wired, to prevent bending ; which wiring 

 alfo forms a receptacle for the putty. Then proceed in the 

 fame manner, with the remainder of the pipes, until the 

 bottom one nearly reaches the furface of the water, but not 

 quite. The fire-pan is to be fupported on two timbers, 

 placed for that purpofe acrofs the top of the wall, and a 

 conical cover may be fitted over it to prevent the heat from 

 paffing away too rapidly, and to confine it to the fides of 

 the pipe. The apparatus being thus fixed, it foon be- 

 comes filled with air of the fame quality as that in the well ; 

 and as their power of gravity is the fame, both the external 

 and internal air become ftationary, from which there can be 

 no good effeft. To put the experiment into execution, fill 

 the fire-pan with lighted charcoal or wood, &c. the copper- 

 pipe which is furrounded by the fire, being by this means 

 heated, a rarefaftion of the internal air takes place, which 

 air by this means is hghtened, and the external denfe air, 

 continuing to prefs with the fame weight as firft into the 

 bottom of the tube, the equilibrium is deftroyed, and a fuc- 

 ceffion of noxious air pafles up through the pipe, as through 

 the funnel of a chimney, till the whole quantity is carried 

 off ; after which the pure air, which has in the meantime 

 introduced itfelf into the well, begins to pafs off by the fame 

 paffage fo long as the fire is continued, though the ftream of 

 air paffing out of the top of the vertical-pipe feems fmall, yet 

 the effeft is great, becaufe that ftream confifts entirely of 

 noxious air that is required to be removed. The effe£t will 

 be greater when the fire-pan is placed lower on the pipe, as 

 by that means more external air becomes rarefied ; but if the 

 fire-pan is placed too low down in the well, the charcoal fire 

 produces carbonic acid gas in great quantities, and renders 

 the air in the well unfit for refpiration. 



Well, in jlgrkuhure, a term fometimes applied to a 

 fort of pipe-chimney or vent-hole left in a ftack, rick, or 



W E L 



mow of hay, or other fimilar materials, in order to pre* 

 vent its being overheated. Such vent-holes fhould be 

 avoided as much as poffible in all cafes, as injuring and 

 deftroying much hay about them, and being hurtful in , 

 other ways. See Stacking Hay. 



Wells, Ebbing and Flonving, in Rural Economy, fuch 

 as have their waters rifing and falling in an almoll mo- 

 mentary alternate manner. See Spring, and Well. 



Wells, Farm or Field, in Jlgriculture, fuch as are dug 

 in thefe fituations for the ufe of live-ftock. 



Wells of this fort are of much ufe and coHvenience, as 

 they prevent the trouble and difadvantage of driving cattle 

 to diftances for the purpofe of getting water. See Pond. 



Well, in the Military Art, denotes a depth which the 

 miner finks into the ground, from which he runs out 

 branches or galleries, either to prepare a mine, or find 

 out, and difappoint, the enemy's mine. 



Well, in a Ship, an apartment formed in the middle of 

 a (hip's hold to inclofe the pumps, from the bottom to the 

 lower deck. It is ufed as a barrier to preferve thofe ma- 

 chines from being damaged by the friftion or compreffion 

 of the materials contained in the hold, and particularly 

 to prevent the entrance of ballafl, &c. by which the tubes 

 would prefently be choaked, and the pumps rendered in- 

 capable of fervice. By means of this enclofure, the artifi- 

 cers may likewife more readily defcend into the hold, in 

 order to examine the ftate of the pumps, and repair them as 

 occafion requires. Falconer. 



Well of a Fijhing Veffel, an apartment in the middle of 

 the hold, which is entirely detached from the reft, being 

 lined with lead on every fide, and having its bottom pierced 

 with a fufficient number of fihall holes, paffing alfo through 

 the ftiip's floor, fo that the falt-water running into the well 

 is always kept as frefh as that in the fea, and yet prevented 

 from communicating itfelf to the other parts of the hold. . 

 Falconer. \ 



Well alfo implies in the fame range, or even with a fur- 

 face. 



WELL-Z)ra;n, in Agriculture, that fort of vent or dif- 

 charge for the wetnefs of land, which is conftrufted in fome- 

 what the well or pit manner. See Vi siA^-Draining, and 

 SpRiNG-Z)ra;n/«^. 



WELL-Draining, that means of clearing lands from wet- 

 nefs which, in certain flat fituations, is accomphftied by mak- 

 ing large deep pits or wells, and the conftant or occafional 

 ufe of fuitable machinery. In the execution of the bufinefs 

 of forming a draining well in loofe ground, a ftrong wooden 

 frame is neceflary to be funk, as the work of digging the 

 well or pit proceeds ; the fides of which being made, fo as 

 in the end to be fufficiently open or permeable, to admit 

 the water to enter freely within it, and clofe enough to pre- 

 vent grofler njatters from interrupting the machinery ; efpe- 

 cially when of the mill kind. The fize of the frame for 

 this purpofe muft, confequently, be adapted and fuited to 

 the nature of the engine which is employed. The laves of 

 a mill, it has been obferved, would require a length of 

 frame, which muft neceffarily be proportionally ftrong ; but, 

 that for a pump, a frame of inconfiderable expence would 

 be fufficient ; whether of wood or uncemented brick-work. 



In this fort of draining, which is applicable in many cafes 

 of cold wet flat lands lying in the valley-trafts in moft parts 

 of the country, the wetnefs is drawn ofl^ by thefe forts of 

 powerful machinery, working in the fpring time, after wet 

 feafons, or at other periods when neceflary or wanted. See 

 SpRl^G-Draining. 



WELL-Grown, in Ship- Building, implies, that the grain of 

 the wood follows the fliape required, as in knee-timbers, &c. 



Well- 



