in commerce, a sort of stuff deriving all its confidence merely from being fulled, or wrought with laces and size, without either spinning or weaving.

Felt is made either of wool alone, or of wool and hair. Those of French make, 3½ yards long, and 1½ broad, for cloaks, pay each £1.14s.1½d. on importation; and draw-back £1.12s.3d. on exporting them again.

FELT-SPAR, or Rhombic Quartz, the petunse of the Chinese, a genus of siliceous earths, according to Cronstedt, resembling the jasper in most respects. Its German name is feld-spat, from the word feld, which signifies a field, and likewise a compartment or regular surface. Hence, according to Mr Forster, the word feld-spat signifies a spar composed of little compartments of rhombic or other figures. It strikes fire with steel, and melts in a violent heat. M. Bayen, who analysed it by acids, obtained a considerable quantity of argillaceous and siliceous earths, a smaller quantity of magnesia, and a still smaller of calcareous earth and iron. It is found either sparry or crystallized. The former species has several varieties. 1. White. 2. Reddish brown, occurring in the Swedish and other granites. 3. Pale yellow. 4. Greenish, resembling the schorl or cockle spar, but less fusible, and more irregular in the figure. The crystallized kind is found in an iron mine in Westmanland in Sweden, seldom in the form of veins, and still more rarely constituting the substance of whole mountains, but generally mixed either with quartz or mica; in which case it is called granite. When mixed with jasper, along with some particles of quartz, cockle, and horn-blende, it is named porphyry.

Another kind of this stone, named by M. Bayen white felt-spar, is found in the duchy of Lorraine. It is of an opaque white colour, spotted on the outside with ochre. It consists of shining particles, which give it a sparry appearance; it is very hard, and strikes fire with steel, is affected by acids; and when analysed by them, appears to contain one half its weight of siliceous earth, the other being composed of magnesia and iron.

Analogous to the felt-spar is that beautiful stone named Labrador-flone, lately brought to Europe. It was discovered some years ago by the Moravians, who have a colony among the Equimaux, in the country of Labrador in North America. It is found of a light or deep-grey colour, but for the most part of a blackish grey. When held in the light in various positions, it discovers a variety of colours, such as the blue of lapis lazuli, glass-green, apple-green, pea-green, and sometimes, but more seldom, a citron-yellow. Sometimes it has a colour between that of red copper and tombuck-grey; at other times the colours are between grey and violet. For the most part these colours are in spots, but sometimes in stripes on the same piece. The stones are found in pretty large angular pieces, appear foliated when broken, and the fragments of a rhomboidal figure. Their specific gravity, is about 2.755, and in other respects they agree with the felt-spar. Werner informs us, that he has seen a piece of felt-spar at Gayer, which showed a great variety of colours, but very pale.

Mr Kirwan observes on the felt-spar, in general, that it is found of many different colours, as white, yellow, red, brown, green, violet, &c., sometimes crystallized in rhombs, cubes, or parallelopipeds; at other times without any regular figure. It breaks like spar, but the texture is close though lamellar. The specific gravity, according to our author, is from 2.400 to 2.600, but Mr Gerhard says he found it as high as 3.500; in which case Mr Kirwan is of opinion that it was mixed with some metallic particles. It is harder than the fluor spar, but less so than quartz. It also melts without addition more perfectly and easily than the fluors, forming a whitish glass, which does not corrode the crucibles as that from fluor does. It is entirely dissolved without effervescence by the microcosmic salt and by borax; but unites with difficulty to fixed alkalies. In its crystallized state it decrepitates in the fire, but not otherwise. It is found in loose masses, about two inches long at most, without forming either veins or strata. It is also found mixed with sand or clay; or it is sometimes found imbedded in other stones, as granite, &c. One hundred parts of the white spar contain 67 of siliceous, 14 of argillaceous, 11 of ponderous earth, and 8 of magnesia. According to Mr Kirwan, it is undoubtedly the stone used by the Saxons, as petunse, in their porcelain manufactures.

Cronstedt, who supposes this stone to be of the same nature with jasper, remarks, that "if the rhombic quartz and jasper were of the same species, that fort of porphyry which is made up of these two bodies ought only to be ranked with the jaspers, instead of being placed with the faxes. It is observable, however, in old monuments, which have been long exposed to the air, that though porphyry had decayed in such a manner as to lose its polish, yet granite, though equally old, and composed for the most part of rhombic quartz, has preserved its lustre. This, however, does not contradict the possibility of rhombic quartz being the same substance with the jasper: the calcareous spar, for instance, being found to bear the weather, and even fire, better than limestone."