MATERIALS FOR BRICKS, POTTERY AND PORCELAIN. 89 



acquired notoriety, from the fact that some of its varieties may be woven into cloth which is 

 indestructible by heat. It is to uses similar to these that it is accordingly applied, being em- 

 ployed in the preparation of the incombustible cloth proposed for firemen's robes, and for the 

 lining of the metallic safes now so generally introduced into counting houses. 



MATERIALS FOR BRICKS, POTTERY AND PORCELAIN. 



The localities of clays suitable for the manufacture of brick and the common kinds of 

 earthen ware, are too numerous in this State to be here introduced, and their description be- 

 longs rather to the department of geology than to that of mineralogy. Many of these have 

 already been noticed in the Reports of the Geologists ; and Mr. Mather has presented some 

 details, which show the importance of the branch of industry included under the art of brick- 

 making. 



The manufacture of the finer kinds of pottery has not heretofore been carried on with much 

 success in our country. Whether this be owing to the superior facilities which are possessed 

 by the English and French in regard to materials, or to the reduced price of labour, it is not 

 easy to determine. My present object is merely to show that New- York is not destitute of 

 the materials necessary for this branch of art. 



The finer kinds of pottery require for their manufacture the purest clays ; such as contain 

 little or no oxide of iron, and which consequently do not turn red in burning. To these a 

 portion of pure silica is added, which is prepared for the purpose by heating masses of flints 

 or quartz, quenching them in water, and then reducing them to powder in a mill. 



Clays of good quality occur abundantly in various parts of Staten and Long Islands ; and 

 upon proper trial, they would no doubt be found to answer the purposes of this manufacture. 

 There are also several localities in Orange county, where similar materials may be obtained. 



Near Southfield furnace in the latter county, is a bed of decomposed feldspar, known by the 

 name of porcelain earth, which will probably be of great value in the manufacture of pottery. 

 This substance is of a pure white colour when dry, a little unctuous, and is supposed to be 

 abundant. 



According to Dr. Emmons, porcelain clay, arising from the decomposition of labradorite, 

 occurs near the village of Mclntyre in the county of Essex. There is also an important lo- 

 cality at Minerva in the same county. 



In Warren county, porcelain clay is found in abundance in the towns of Athol and Johns- 

 burgh. It is white, soft to the touch, and probably contains an admixture of talc. The white 

 is interlaminated with layers of different colours, as yellow, red and brown. The quality of 

 this clay has, upon trial, been ascertained to be good. 



It is now generally admitted that these clays owe their origin to the decomposition of feld- 



