G R A 



tliat tlie larger ftonea of the bladder are diffolved or dim1- 

 nifhed hy the aftion of alkaline medicines, yet the fmaller 

 concretions appear to be prevented from forming, and great 

 relief from the pain and irritation, imder all the varieties of 

 concretion, is produced by the ufe of them. PeiTy's fol- 

 vent, Mrs. Stephens' medicines, and Chittick's Receipt for 

 the Hone, are all of the alkaline clafs. It is probable that 

 thefe alkaline medicines operate principally on the flnids in 

 the hrft palfages, by nentrallzing the acids occafioned by 

 indigeflion, rather than by paffuig in the circulation, and 

 combining with the uric acid in the kidnies or bladder. 

 Tliis would appear, partly from the faft, that the carbo- 

 nated alkalies are equally or even more beneficial than the 

 pure or cauftic alkalies, in relieving the fymptoms of Hone 

 or gravel ; but it is principally proved by a circumllance, 

 recently afccrtained by the experiments of Mr. Home and 

 Mr. Brande, tliat the abforbent e \rths, efpecially magnefia, 

 are conliderably more eflicacious in relieving thole fymp- 

 toms, and in diminidiing the quantity of uric acid in the 

 urine, than the alkalies thcmfelves. The magnefia is to be 

 given in moderately large dofes, two or three times a day ; 

 and if it proves purgative to tl'.e bowels, a few drops of the 

 tincture of opium may be added to it. (See Philofoph. 

 Tranfaft. part i. for 1810.) 



Of the alkalies, it would appear that the potafs is, on the 

 whole, more beneficial in thefe complaints than the foda: 

 the pure or caullic potafs may be given freely, beginning 

 with dofes of fifteen or twenty drops, and gradually increaf- 

 ing it, well diluted with any thin drink; and it may be con- 

 tinued for a confiderable time with perfeft fafety. But the 

 carbonate of potafs is not lefs nfeful, and, efpecially when 

 dilTolved in water faturated with carbonic acid gas, it is 

 more agreeable, and probably more efficacious. The effi- 

 cacy of thefe acidulous alkaline waters was at firft indeed 

 attributed to the carbonic acid which they contain, and not 

 to the alkali. (See a Medical Commentary on Fixed Air, 

 by Dr Dobfon ) The foda water acidulated by the fame 

 gas operates in a iimilar way, and is another agreeable mode 

 of taking the medicine. Lime-water is likewife pofiefied of 

 fome remedial powers, but is lets efficacious than the alka- 

 line water. 



All thefe aqvieous liquors operate in fome meafure, per- 

 haps, upon another principle ; that of increafing the quan- 

 tity of fluids which pafs through the urinary organs, and 

 thus of diluting the irritating uric falts, and conlequently 

 dimiiiifhing the diftrefs which they occafion: and they may 

 likewife operate negatively, by rendering the patient un- 

 able to drink the ufual quantity of wine or other ftrong 

 liquors. Other matters, which tend to increafe the flow of 

 urine, feem to relieve the fymptoms of gravel, upon the 

 principle of dilution; efpecially fmall dofes ot the nitrous 

 Ktlier, or fpirltns xthcris nitrofi, of the pharmacopoeias. 



When extreme pain is excited, either by the palling of a 

 fmall concretion along the canal of the ureter or of the ure- 

 thra, opiates will afford a temporary relief to the iutFerings 

 of the patient, and will perhaps aid in relaxing any fpaf- 

 modic contraction that may take place in thefe pafTages, 

 and thus expedite the palfage of tlie calculus. The fame 

 object may be promoted by the ufe of the warm bath, by 

 fomentations to the loins and pubes, and by warm glyfters. 



For the modes of relieving the fymptom:, conneftcd 

 with the prefcnce of the larger calculi of the bladder, and 

 of extracting thefe concretions by furgical means, fee 

 SroNF.: — fee alio Nei-iiral<iia and Nephritis. 



GRAVELAINAS, in Geography, a town on the S.W. 

 -coaft of the ifiand of Negroponte, on the fcite of the an- 

 cient Eretria; 10 miles S. E. of Negroponte. 



-G R A 



GRAVELINES, a fea-port town of France, in tli? 

 department of the North, and cliief place of a canton in 

 the diftrict of Bergues, fituated in the Englifla channel, at 

 the mouth of the river Aa. Although it is not large, it 

 is well fortified with baftions, half-moons, and horn-work, 

 and the adjacent country is interfedled by canals, one pafs- 

 ing to Dunkirk by Bourbourg, and another direftly to 

 Bergues. It was built in 11 60, and ceded to France by 

 the peace of the Pyrenees; 9 miles W.S.W. of Dunkirk. 

 N. lat. 50" 59', E.long. 2°. 



GRAVELLANO, a town of Italy, in the department 

 of the Gogna ; 30 miles N. of Novara. 



GRAVELLING, among Farriers, a diforder incident 

 to travelling horfes, occafioned by little gravel-ftones get- 

 ting in between the hoof and the (hoe, which, fettling to 

 the quick, fret and fefter the part. 



It is cured by pulling off the fhoe, drawing the place to 

 the quick, picking out all the gravel, and poulticing the 

 foot, rather than itojiping it, according to the old pra&ice, 

 with horfe-grcafe and turpentine poured in hot. 



GRAVELLY IjANd, a term applied to fuch land as 

 refts upon a fub-fl:ratum of the gravel kind, or which is 

 much intermixed with that fort of material. This fort of 

 land is generally light and dry when under the plough, but 

 apt to burn in the furamer feafon, when in the condition 

 of grafs. 



The manures fliould be adapted to the particular natures 

 of thefe lands; but where they are of the more light de- 

 fcriptions, they may be greatly improved by the ufe of 

 marie, loamy clay, chalk, mud, and other fimilar matters, 

 as well as diflcrent forts of earthy comports. See Soil. 



Gravelly Soil, a term fignifying that fort of foil, 

 which is chiefly conftituted of gravelly matters. See Soil, 



GRAVEN, in GiOgrnphy, a town of Norway, in the 

 diocefe of Bergen; 42 miles S.S.W. of Bergen. 



GRAVENAU, a town of Bavaria; 20 miles N. of 

 PafTaii. N. lat. 48-^ jl8 . E. long. 13 ■ 22'. 



GRAVENWERT, a town of Bavaria; 15 miles N. 

 of Amberg. 



GRAVER, a ftecl inftrument, ferving to engrave on 

 metals. 1'lie graver confills of four fides or faces, and 

 the point ufiially terminates in a lozenge: in fome it i» 

 round, and in others fquare. The round point is befl for 

 fcoring lines, the fquare for cutting broad and deep, and 

 the lozenge for more delicate and fine flrukcB and fcratches. 

 I^e Bofle recommends thofe of a form betwixt the fquare 

 and lozenge. See ENGRAViKt;. 



The gravers (hould be made of the befl: fteel, which 

 mufl: be drawn out into fmall rods with a charco;J fire. 

 Thefe rods, after having been cut into the proper lengthg 

 for gravers, fliould be foftened, by heating them in a char- 

 coal fire, and fiifTering them to cool very flowly: let them 

 next be filed into the defired form, and brought back to a 

 hard temper by heating tliein red-hot, and in this ftate 

 dipping their ends into foft foap. This fliould be done 

 in a perpendicular direction; for, if they be turned in the 

 leafl: degree obliquely, the graver will warp and be crooked. 

 If the temper of tlie graver be too hard after this treat- 

 ment, ami prevent the whetting it properly to an edge, it 

 may be foftened, by laying its end on a large burning 

 piece of charcoal till it begins to grow yellow, and then 

 thrufting it into a lump of tallow, or dipping it in water; 

 but if water be ufed, the graver mull not be too hot. It 

 may be known whether ths graver be tempered to a pro- 

 per hardnefs by touching the edge of it with a file, which, 

 if any efleft attends it, proves the temper to be too foft. 

 The bell proof of too great hardnefs is the breaking of the 



poiut 



