SERPENTINE. 



choidal ; the fragments are tranflucent at the edges ; the 

 luflre is fomewhat refmous, and when powdered, it has an 

 unftuous foapy feel. The fpecific gravity varies from 

 about 2.6 to 2.7. Serpentine feems nearly aUied to the 

 mineral called hornblende, from which it differs in its conlli- 

 tuent parts by containing more magnefia and lefs iron. 

 Chrome has been found in fome Terpentines. The analyfis 

 of different ferpentines fhews a confiderable variation in the 

 proportion of their conftituent parts, 

 from 45 to 29 Silex, 



18 23 Alumine, 



23 34 Magnefia, 

 3 4 Iron, 



II 10 Water and lofs. 



Some ferpentines contain 6 per, cent, of lime. 



The difciples of Werner 'divide Terpentine into two 

 fpecieo, the one called the noble Terpentine, the other the 

 common ferpentine ; the former they ceniider as older, and 

 having a different geological pofition to the common ferpen- 

 tine ; but for this diftinftion there does not appear fufii- 

 cient reafon, as the fame beds will furnirti fpecimens of 

 both kinds. The noble ferpentine has the richelt variety 

 of colours and the greatelt degree of tranflucency. Ser- 

 pentine, though not very rare in many alpine diltrifts, is 

 by no means fo common as granite, (late, and limeltone. 

 Serpentine occurs in beds in gneifs and primary limeftone, 

 and in mica-flate : it alfo covers many rocks in amorphous 

 mafTes, and may be obferved graduatmg into chlorite or talc- 

 flate. Serpentine has been remarked to exilt generally at a 

 low level in alpine diitrifts ; but there are fome remarkable ex- 

 ceptions to this, particularly in the fummits which furround 

 the central parts of mount Rofa, in Switzerland. Thefe 

 fummits have an elevation of more than 1700 fathoms, 

 formed of beds of ferpentine lying in a poiition generally 

 horizontal. 



Serpentine is more abundant in Europe, than any other 

 part of the globe that has been yet explored. The whole 

 front of the Alps facing Italy contains ferpentine almoil in 

 every part, although there is very little in the fide towards 

 Switzerland. It extends through Italy, where it is culled 

 gabbio. Oneof the fineft varieties is at the hills of Im- 

 pronetta, near Florence : it contains much of that green, 

 femitranfparent, and fattiny fubilance, which SaulTure calls 

 fmaragdite, on account of its fine emerald-green colour. 

 France has fome mountains of ferpentine, efpecially in 

 Limoufin. 



The fineft ferpentines of Spain are from Sierra Nevada ; 

 two leagues from Grenada, they have a green bafe filled 

 with gliflening plates of a yellow colour. Superb columns 

 have been made of it, which decorate the churches and 

 palaces of Madrid. According to Patrin, ferpentine is 

 almoil entirely wanting in northern Afia, with the excep- 

 tion of the eaftern part of the Ural mountains, which fepa- 

 rate Europe from Afia. There are fome hilk of ferpen- 

 tine, which at great intervals accompany their bafe, follow- 

 ing their direftion from north to fouth ; there are alfo 

 fome detached branches which appear near Tobolllc, which 

 is not far from thefe mountains. But from hence to the 

 river Amur, a fpace of about three thoufand miles, fcarcely 

 any veftiges are found either in the great chains of Altai, 

 Sayennes, or the mountains of Daouria. The ferpentines 

 moft known in Europe are thofe of Saldbergh in Sweden, 

 and Zeobhtz in Saxony, from which vafes of every kind 

 are turned and exported to diltant countries. The ferpen- 

 tine of Bayreuth is filled with garnets of the fize of a pea, 

 difperfed equally through the mafs. When the Hone is 

 pohihed, they prefent a pleafing mixture of fine red fpots 



in a green bafe. Trinkets and other ornaments are made 

 of it. 



The mountain called Roth Horn, or Red Horn, which 

 faces mount Rofa towards Italy, is elevated 1506 fathoms; 

 it is compofed of immenfe maffes of terpentine of an irre- 

 gular ftiape. The furface of this ferpentine becomes a 

 deep red by the adfion of the atmolphere, which oxygenates 

 the iron it contains. It is this colour, and the elongated 

 form, that have occafioned the mountain to be called Red 

 Horn. 



The ferpentine of this mountain is covered by a ileatite 

 of a fea-green colour, mixed with carbonate of lime and 

 grains of felfpar. On this ferpentine are laid beds of 

 micaceous fchill, intermixed with limeftone, compofed of 

 more than one half of mica. Thefe are again covered by 

 ferpentine : all the beds are nearly horizontal, riling a little 

 towards mount Rofa. 



Mount Crevin, another mountain near mount Rofa, is an 

 inaccellible obelilk of a triangular form, wliich is elevated 

 2309 fathoms above the fea. It is compofed of three dif- 

 tinft mades ; the uppermoft, which forms the fummit, is of 

 a yellow ifabella colour. It is compofed of ferpentine 

 mixed with micaceous fchift, containing limcitone and quartz. 

 The middle is of gneifs and micaceous Ichift, and the lovifer 

 one or bafe of the pyramid is ferpentine ; but the moft re- 

 markable hill of ferpentine is in the chain of mountains 

 that leparatesthe marggravate of Bayreuth from the Upper 

 Palatinate. Its elevation above the plain is about 300 feet ; 

 it extends in a direftion from eaft to weft. The rocks 

 which crown the fummit are of very pure ferpentine, 

 divided into beds, and repofing on gneifs and hornblende. 

 M. Humboldt having brought his compafs near thefe rocks 

 of ferpentine, faw with furprife, that the north pole of the 

 needle flew round to the fouth. He further obferved, that 

 the rocks on the northern and fouthern declivities have op- 

 pofite poles. The eaftern and weftern extremities of the 

 hill do not exert any aftion on the magnetic needle, though 

 the appearance of the ftone is the fame as on the north 

 and fouth declivities. In the magnetic parts of the hill 

 certain rocks are alfo obferved, which are not magnetic in 

 junftion with fimilar rocks, that exert a Itrong aftion on 

 the needle, fome of them at the dillance of 22 teet. The 

 mountain not only exerts its aftijn on the needle in its 

 whole mafs, like fome other hills, it is manifeft even in 

 fmall fragments. 



Humboldt obferved, that minute fragments are brifkly 

 moved on prefenting them to the point of a weak magnet ; 

 but they have not the leaft attraftion for iron not mag- 

 netized. Humboldt convinced himfelf that this ferpentine 

 does not contain an atom of magnetic iron, all which it con- 

 tains is in the ftate of oxyd. Its fpecific gravity is much 

 lefs than that of other ferpentines, fcarcely reaching to 

 2000, that of common ferpentine being upwards of 2700. 

 This mountain of ferpentine, taken in the aggregate, may 

 be regarded as one large natural magnet, having two poles, 

 the part equidiftant from each difplaying no figns of 

 magnetic power, as is the cafe with fmdl natural and 

 artificial magTiets. Like them too, if a fragment be broken 

 from the mafs, each fmall piece has it? north and fouth 

 pole, and a central part, which is not magnetic. That par- 

 ticular kind of foft ferpentine, which is capable of being 

 turned into veflels that refill the aftion of the fire, is called 

 pot-Hone, and has been already defcribed. See PoT- 

 Slone. 



Steatite and amianthus, a fibrous aftjeftus, are almoft 

 always ailociated with ferpentine. (See Asbestus and 

 Steatite.) The fineft amianthus occurs in Corfica form- 



2 ing 



