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leaves, and making a very pretty appearance. We do not 

 find that they have any fcent. Ca/yx rofe-coloured, half an 

 inch in diameter. Corolla and Jlamsns flefh-coloured. The 

 name of Poiretia, given by Cavanilles, was not publiflied till 

 three years after our Sprengel'ia. 



2. S. montana. Mountain Sprengelia. Br. n. 2. — 

 « Anthers \mconnefted, beardlefs. Calyx partly coloured. 

 Points of the leaver ftiort."— Gathered by Mr. Brown in 

 Van Diemeu's illatid. We have feen no fpecimens of this 

 Ipccics. 



Mr. Brown's PoKCELETiA (fee that article), as well as 

 his Anderfoma, Prodr. Nov. HoU. v. I. 553. Ait. Hort. 

 Kew. v. I. 321, feems very nearly related to the prefent 

 genus, both in afpccl and charafter. 



SPRETZA, m Geography, a river of Bofnia, which 

 runs into the Bofna. 



SPREWIL, a town of North Carolina, on the fouth 

 coait of Albemarle found. N. lat. 35° 56'. W, long. 



76° 39'- 



SPRIG, a fmall eye-bolt, ragged at the point. 



Sprig is alfo a fmall branch or fpray. It likewife fig- 

 nifies a brad. 



SPRIGE, in Geography, a lownlliip of Ohio, in the 

 county of Adams, containing 1664 inhabitants. 



SPRIGNO. See Spigno. 



SPRING, FoNS, in Natural Hiftory, a fountain or 

 fource of water, rifing out of the ground. 



The origin of fprings or fountains has been much con- 

 troverted among our late naturalifts. Meflrs. Mariotte 

 and Perrault afcribe them to rain, to which others have 

 added dew ; their doftrine is, that the rain-water penetrates 

 the earth till fuch time as it meets a clayey foil, or ftratura; 

 which proving a fufiicient folid bottom to fuftain and ftop 

 its defcent, it glides along it that way to which the earth 

 declines, till meeting with a place, or aperture, on the fur- 

 face, through which it may efcape, it forms the head of a 

 river. 



Now, that the rain is fnfficient for this effeft, appears 

 hence ; that, upon calculating the quantity of rain and 

 fnow which falls yearly on the traft of ground, that is 

 to furnifh, for inltance, the water of the Seine, it is found 

 that river does not take up above one-fixth part of it. 



Springs ordinarily arife at the bottom of mountains : the 

 reafon, they fay, is, that mountains coUeft the moll waters, 

 and give them the greateft defcent the fame way : and that 

 if we fometimes fee fprings on high grounds, and even on 

 the tops of mountains, they muft be brought from other 

 remoter places confiderably higher, along beds of clay, 

 or clayey ground, as in their natural channels. If, then, 

 there happen to be a valley between a mountain on whofe 

 top is a fpring, and the mountain that is to furnifh it \vith 

 water, the fpring muft be looked on as water condufted 

 from a refervoir of a certain height through a fubterra- 

 neouo channel, to make a jet of an equal or fomewhat lefs 

 height. 



This theory M. de la Hire (Parifian Mem. for 1703) has 

 taken under examination, in its moft effential article, and 

 that where the authors feem to have been the leaft diitruft- 

 ful. He has endeavoured to find by experiment, whether 

 rain or fnow-water could penetrate the earth as low as the 

 clayey ftratum : with this view he procured a leaden veflel 

 eight feet deep, having a pipe at the bottom : this he buried 

 in the earth, and filled with foil of fand and loam, expofing 

 the furface to receive all the rain that fell. After fifteen 

 years' trial, he found that no water had run through the 

 jpipe at the bottom. Again, he took another veflel, eight 

 inches deep, which he filled with earth, and expofed in like 



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manner. No rain penetrated fo as to run out at the bot- 

 tom from June to February ; but after that time it yielded 

 a quantity after moft rains. Another veflel of twice the 

 depth, or fixteen inches, gave a refult much like that of 

 eight inches. When herbs were planted in this lalt-men- 

 tioned veflel, he found that as foon as ever any of thefe 

 came up, and were grown to any bulk, fo far was the rain 

 that fell from being able to gather itfelf at the depth of 

 fixteen inches, that it was not fufficient even to feed the 

 plants, but there was a neceffity for watering them. 



With refpeft to the firft-mentioned faft, fays Mr. Dal- 

 ton, (Manchefter Memoirs, vol. v.) we need not won- 

 der that no water penetrated through eight feet of earth 

 at Paris, where the annual rain is but 20 inches, when 

 only eight or nine inches penetrated through three feet of 

 earth here, where the rain is 33 or 34 inches annually. 

 But it does not follow, that rain may not defcend down 

 declivities of the ground into vallies or lower parts, at Paris 

 as well as here, and being accumulated, may penetrate into 

 the earth to a confiderable depth, efpecially if it meet with 

 channels or chafms of any kind, or declining ftrata of earth, 

 that are impenetrable by water. Paris, Mr. Dalton believes, 

 however, is not very liberally fupplied with fprings, as might 

 be expefted. As to the experiment upon vegetation, it 

 only proves that the rain in fpring and fummer is fometimes 

 not fufficient to fupport vegetable life, a faft which may 

 readily be granted ; but then in his experiment the plants 

 were precluded from a fupply of moifture from the earth 

 beneath the veflel, which is a referve of the utmoft confe- 

 quence in dry feafons. 



This circumftance of water afcending again in the earth, 

 on whatever principle it is effefted, cannot be denied. There 

 were four inches and three-quarters of rain here in July laft, 

 none of which pafled through the earth in the evaporating 

 veflel ; this earth, however, at the end of the month, was 

 far from that degree of drynels which is unfit for the fup- 

 port of vegetation. During the firll four days of Auguft 

 there fell about three inches of rain, and only half an inch 

 penetrated through the earth in the evaporating vefTel, 

 Confequently three feet in depth of earth that was mode- 

 rately moiit imbibed nearly three inches of rain, before it 

 was faturated ; whence we may conclude, that three inches 

 nearly had afcended and been evaporated. This evidently 

 fhews, that earth is capable of holding a very great pro- 

 portion of water, that in fummer the water afcends to fup- 

 ply the exigencies at the furface, and that earth far under 

 the point of faturation with moifture is itill fit to fupport 

 vegetation. 



This obfervation fuggefted the following queftion — How 

 much water is there in a given depth of earth, when the 

 foil is at the point of faturation, or in that ftate, when it 

 begins to yield water from the lower pipe of the evapo- 

 rating gauge I 



To determine this, Mr. Dalton took a quantity of garden 

 foil, that had been foaked with rain a day before, and prefTed 

 it into a crucible ; in this ftate he found its fpecific gravity to 

 that of water, as fis-e to three. It was then expofed to a 

 moderate heat, till it appeared, as near as he could judge, of 

 the fame moifture as garden foil two inches deep in dry 

 fummer weather ; afterwards it was expofed almoft to a 

 red heat, till it became a perfeftly dry powder ; in the for- 

 mer cafe it loft one-twelfth of its weight, and in the latter 

 one-third. When it had lofl one-fixth, it did not appear 

 too dry to fupport vegetation. When it had loft two- 

 ninths, it appeared like the top foil in fummer. Hence it 

 follows, that every foot of earth in depth, fo faturated, 

 contains feven inches of water, and that it may part with 



a quarter 



