EARTHS. 287 



Romans ;* the celebrated Etruscan vases were found in the tombs 

 of lower Italy, f 



Water pipes were made by the ancients. I have one from Smyr- 

 na, sent out by the American missionaries, which indicates its anti- 

 quity by numerous layers of carbonate of lime, accumulated in the 

 tube to the thickness of three or four inches, and evidently deposited 

 from the water which ran through it. 



The Egyptians ornamented the mummies in their catacombs, not 

 only with glass, but with earthen figures, some of which were cover- 

 ed with a blue glazing made by the oxide of cobalt, the same mate- 

 rial that is now used for this purpose. Porcelain was made by the 

 Persian, and other eastern nations, before the Christian era, and the 

 art is of high antiquity in China and Japan. It was introduced into 

 Europe, early in the late century, and fabricated first in Saxony and 

 France ; it was established in England, about the middle of the 

 late century, and the manufacture was brought to great perfection, 

 by the late Mr. Wedgwood.f The manufacture of porcelain has 

 been within a few years, begun in the United States,^ and beautiful 

 porcelain is now made at Philadelphia, by Hulme and Tucker. 



Materials of porcelain. The Romish missionary, father D'En- 

 trecolles, early in the 18th century, sent home some of the materials 

 used by the Chinese, and called by them petuntze and kaolin, the 

 former being undecomposed felspar, and of course fusible ; the lat- 

 ter decomposed and infusible, in consequence of the loss of the al- 

 kali, which is one of its constituent principles. 



The felspar is composed of silica about 60 or 70, alumina from 

 15 to 25, and from 10 to 12 per cent, of potash or soda. 



Porcelain differs from stone ware in having a vitreous fracture and 

 delicate translucence, which arises from its being composed of one 

 fusible ingredient, while the infusible one preserves the vessels from 

 losing their form in the fire. 



Porcelain clays abound in this country, and the materials from 

 Chester County, near Philadelphia, now used there, are of the first 

 order in point of excellence. Such clays should be free from iron, 

 or the ware will be colored. 



Materials of pottery. There is no difference in principle between 

 the materials of pottery and those of porcelain, except that the latter 



* Specimens are in Yale College, brought out by Dr. Howe and Mr. Jones. 

 Some of them are supposed to be of the age of Pericles, particularly those from the 

 tombs near Athens. Dr. Howe informed me that he was present when they were 

 taken from the tombs. 



t I saw a collection of these in the British museum, sent out from Italy by the 

 late Sir Wm. Hamilton. 



t The common pottery had been manufactured in England, time out of mind. 



I believe that Dr. Meade, of New York, was the first person who succeeded in, 

 this country in making true porcelain. 



