38 
mg of earthen ware of various kinds, and also in the fabri¬ 
cation of articles for numerous domestic purposes. The 
coarser kinds of ware are made in almost every district in 
this country, directly on the clay used in their composition. 
Several establishments for the finer ones, have lately been 
erected, and in Vermont, an incorporated company intend 
to manufacture porcelain.* 
Mica or isinglass is in general classed with aluminous 
fossils. Until within a few years, it was altogether used in 
the Russian navy as a substitute for glass. From its great 
elasticity it is prevented from shattering at the explosion 
of cannon.f It possesses another useful property ; that of 
resisting heat, and for this reason is often employed in the 
construction of stoves and lanterns. 
To these may be added schistus, and hornblende, substan¬ 
ces often occurring. Clay slate (argillite of Kirwan,) is 
the variety used for writing. Whet slate or honeslone 
(JYovaculite) also belongs to this class, and is not un¬ 
common. The hone stone of commerce is brought prin¬ 
cipally from the Levant. Cyanite or sappare (Disthene 
of Haiiy) jasper, and granatite, (Staurotide) have all been 
observed. 
The last primitive earth forming a constituent in the 
composition of minerals, which remains to be noticed, is 
Silex. A few of the species deserve to be mentioned, such 
as quartz, rock crystal, and amethyst. Short and tourmaline 
are often found, and the indico'lite or tourmaline azure of 
Haiiy, a rare mineral in Europe, has not long since been 
discovered at Goshen (Massachusetts.)^ Calcedony , zeolite^ 
inelanite,% semi-opal , garnet, hornstone, woodstone, are all na¬ 
tive substances.jl Flint, so important in war, has been ob- 
* For an elaborate detail of the compositions used for enamels 
in the manufacture of Delft and Wedge wood’s ware, vide 
ChaptaPs Chemistry applied to the arts and manufactures, voL 
4, p. 242. 
f Jameson’s Mineralogy, vol. 1, p. 34. I have to regret my 
inability to avail myself of the volume of this author on Oecon- 
osnical Mineralogy. 
X Bruce, No. p. 123. § Bruce, No. 1, p. 31. 
II Seybert’s catalogue of American minerals, in Coxe‘s Med. 
Museum, vol. 5, p. 155. 
