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R O X 



teracts the force of aggregation, and relieves the molecules 

 from their bonds of union with each other, it certainly is a 

 requifite ; but if bv folution be meant that action of 

 affinities, by which not only the force of aggregation is over- 

 come, but the combinations which conltitute the molecules 

 are deftroyed, it obvioufly is not only unneceflary, but pre- 

 judicial, to cryftallization. Mechanical fufpenfion in a fluid 

 medium of fuch denfity that the crystalline polarity may be 

 enabled to counteract the power of gravity, is, with julticc, 

 confidered by Mr. Smithfon the only requifite for the 

 formation of cryflals. The circumitances here detailed ap- 

 pear an additional confirmation of this remark, and perhaps 

 go ilill farther, by fhewing that even the fluidity (in the 

 common fenfe of the word) of the fufpending medium is not 

 an indifpenfible condition. For it appears impofiible to 

 annex the idea of fluidity to the union of the minute globules 

 which form the jafpideous fubltance, itill lefs to that fub- 

 ftance when formed, or to thofe fpheroids whofe obltinate 

 impenetrability is fo ftrongly defined. And if, by any 

 power of imagination, thefe can be fuppofed to be fluid 

 at the time they retain this conformation ; how can it be 

 fuppofed that the compact, hard, tenacious flone into which 

 they are changed, could retain thefe characters in a fluid 

 ftate ? Yet the fubfequent formation of cryftals proves that 

 either all thefe contradictions mull be, or that the particles 

 of bodies apparently folid, mull be capable of fome internal 

 motion, enabling them to arrange themfelves according to 

 polarity, while they are folid and fixed, as far as they have 

 reference to the ordinary characters of fluidity. 



Inltances, even more remarkable, of the motion of the 

 particles of bodies in a folid ftate, have very long been 

 known and authenticated, though perhaps they have not 

 been generally regarded with the attention they deferve. 

 Glafs veflels are well known to be convertible into Reaumur's 

 porcelain by the internal arrangement of their particles 

 without lofing their external form, and confequently at a 

 temperature very much below that requifite for their fufion. 

 The change of glafs into Reaumur's porcelain does not 

 arife from an evaporation of the alkali, as has been alleged, 

 but from a regular arrangement of the particles of the 

 glafs. It commences by the formation of fibres perpen- 

 dicular to the furface of the glafs, and penetrating into it. 

 At nearly the fame time fmall radiated globules arc formed 

 in the interior of the glafs, and the union of thefe with the 

 fibres, by their mutual mcreafe, forms the whole into a new 

 fubltance ; and if the requifite temperature be longer main- 

 tained, the fibres dilappear, and the whole becomes fine- 

 grained and almolt compadt. This fubltance, from the im- 

 proved ftate of its aggregation, is much ilronger and more 

 tenacious than before, and is not fulible at a heat fuffitient 

 to fufe the glafs it was formed from ; but if that aggregation 

 be once deitroyed, the glafs refulting from its fufion is 

 equally fulible with the original glafs ; and a repetition of 

 the procefs will again form Reaumur's porcelain, which may 

 be again fufed, and fo on repeatedly ; for the quantity of 

 alkali evaporated during the operation is extremely fmall. 

 Tin' hardnefs and brittlcnefs of metals rapidly cooled, con- 

 trailed with the foftuefs and tenacity refulting from their 

 gradual refrigeration, are all analogous inltances ; and all 

 the procefles in which annealing i; employed) and more re 

 markably the tempering of tteel, offer (trong proofs of the 

 internal motions and arrangements of the particles of matter 

 at temperatures very much below the heat requifite for their 

 fluidity. Mr. W.itt further adduces the (tincture and texture 

 of calcareous llalactites as offering proofs of the internal 

 motion of the particles of folid bodies at the common tem- 

 perature of the atmofphere. Succeffive depofitions of cal- 



careous carbonate form a ftalactite which at firfl is fibrous. 

 A continuance of the procefs caufes the fibrous llrudture to 

 difappear, and the ilaladtite becomes irregularly crystalline. 

 The irregularities afterwards vanifh, and it becomes per- 

 fect calcareous fpar, divifible into large rhomboids, with the 

 form peculiar to that mineral, and all the gradations may be 

 found in the fame fpecimc n. For a more particular account 

 of thefe experiments, and the ingenious observations of Mr. 

 Watt, we mull refer the reader to the volume of the Philo- 

 fophical Tranfadtions above cited. The proofs and illuf- 

 trationsof the arrangements which take place in the internal 

 particles of folid bodies, offer the only plaufible explanation, 

 which has yet been given, of the formation and decompo- 

 fition of cryftals under various circumitances in which they 

 occur in mineral veins, and alfo of the prifmatic forms ob- 

 fervable in currents of lava, and in bafaltic and other rocks. 

 SeeTitAP, and Volcanic ProduSs. 



ROW-LOCKS, among Ship-Carpenters, fmall fpaces left 

 in the gunwale, v> here two thoals are let in, at fuch a diftance 

 from each other, as to admit the oar, at the end of the loom, 

 to lie on to row the boat. 



In the fides of the fmallcft veflels of war, a number of 

 little fquare holes, called row-ports, are cut for this purpofe 

 parallel to the furface ot the water. 



ROWNING, John, in Biography, an Englifh mathe- 

 matician and philofopher of confiderable ingenuity, was 

 fellow of Magdalen college, Cambridge, and afterwards redtor 

 of Anderby, in Lincolnfhire. He was chiefly known for 

 mechanical contrivances and inventions. In 1738 he pub- 

 lished a compendious fyftem of natural and experimental 

 philofophy, in 2 vols. 8vo. which was frequently referred 

 to thirty or forty years ago, and which has paffed through 

 many editions, but is now fuperfeded by many other fimilar 

 works of more value. He has likewile two pieces in the 

 Philofophical Tranfadtions, one containing a description of 

 a barometer, in which the fcale of variation may be increafed 

 at pleafure ; the other, giving directions for making a ma- 

 chine for finding the roots of equations univcrfally. He 

 publifhed likewile " A PreliminaryDifcourfeonthe Fluxio;:- 

 ary Method." Mr. Rownin.if. died in November 1 7 7 1 , in 

 the 7 2d year of his age. 



ROWRA1I, in Geography, a town of Hiudoollan, in the 

 circar of Gohud ; 10 miles S. ol Raat. 



ROWS of Trees. See Parallelii-.m. 



ROWSING, in Sea Language, denotes pulling upon a 

 cable or rope, without the allillauce ot caplterns, Sec. 



ROWT, in Rural Economy, a term fignifying to low as 

 cattle. 



ROWTEE, in Geography, a town of Hindooltan, in the 

 circar of Sumbul ; 15 miles S.S.W. of Nidjibabad. 



ROWTOMPOUR, a town of Hindooltan, in Oude ; 

 16 miles S.S.W. of Kairabad. 



ROWTY, in Agriculture, a term fignifying over-rank, 

 or too llrong. 



ROXBOROUGH, in Geography, a townlhip of Phila- 

 delphia county, in Pennlylvania. 



ROXBURGH, a village in Roxburghlhire, Scotland, 

 was formerly a place of confiderable importance, as may be 

 conjedturcd from the circumllance of its having given name 

 to the county. It was for feveral centuries a royal burgh ; 

 and was regarded as one of the lirlt towns in the Scottilh 

 kingdom, tor opulence, and magnificence oi appearance. It 

 was totally deftroyed by king JameG II., and never after- 

 wards recovered ; and as its fcite is now converted into 

 arable fields, the plough has nearly obliterated all traces of 

 its exillence. Somi "1 its ancient cattle, however, 



are yet vilible about two miles eallward from the village. 



'II, u 



