420 GEOLOGY OF THE SECOND DISTRICT. 



Porcelain clays. Those of Johnsburgh and Athol have been described in another place. 

 The clays resulting from the decomposition of labradorile or hypersthene rock, were spoken 

 of under the head of Essex county- 



Moulding sand. Much of the sand of the tertiary beds appears adapted for this purpose. 

 If so, it is quite abundant along the shores of Lake Champlain, wherever this mass has been 

 undisturbed by currents transporting drift. 



Fluxes. It will be found that the transition limestones, when formed of a pure carbonate, 

 are much more suitable for a flux m reducing the ores of iron, than the primary limestone. 

 Thus the birdseyc, winch is very easily broken, might well be substituted for every other. 

 Calcareous spar, or calcite, as it is now called, is probably the best. A large bed of it exists 

 near Port Henry. Clay of the tertiary may undoubtedly be used in some instances as a flux. 



Clay for fire-brick. The only locality of clay for this purpose, which I have examined, is 

 at Adirondack. This, however, does not appear to be sufficiently changed to form a perfect 

 fire-clay, although it is highly refractory ; but it possesses one very remarkable property, 

 namely, that of being heated suddenly, and even raised to a high heat, without cracking. 



Ochres and Stone paints. Among the specular oxides, abundance of this material exists, 

 and probably of the best quality. A thin vein of limonite in Dekalb furnishes the finest mate- 

 rial I have seen, but it is doubtful whether it is in a sufficient quantity to be wrought to 

 advantage. 



Material for copperas. The dissemination of sulphuret of iron is often so abundant as to 

 form a decomposing rock, which may usually be known by its brown color, occasioned by 

 the stains of the decomposed sulphuret. Rocks of this description are quite abundant : they 

 are generally gneiss. Sometimes the sulphuret is in large distinct masses. A locality which 

 appears to furnish the materials suitable for copperas, is in Lewis in Essex county. The 

 manufacture is unprofitable at present ; and probably a sufficient quantity can, for a long time 

 to come, be furnished from the Vermont works. 



Economical materials in the form op simple minerals. 



Mica. Mica for stoves, lanterns, etc., may be obtained in Edwards. It is white, or but 

 slightly tinged with yellowish brown. 



Non-conductors for Safes. Asbestus occurs in only limited quantities in the northern dis- 

 trict. It is in thin seams in the serpentine rocks at Port Henry. It is very fine and soft, but 

 I suspect the fibre is too short for the uses to which it is commonly applied. 



Titanium for coloring artificial teeth. Only a small quantity of this substance has been 

 discovered as yet in the northern district. At Chester, it is found in slender prisms in lime- 

 stone, and farther search may bring to light greater quantities. 



Graphite for drawing pencils. This substance is well known at Ticonderoga, where it 

 forms a regular vein in gneiss. At numerous other places it is found in smaller quantities, 



