554 TRANSACTIONS OP THE AMERICAN INSTITUTE. 



wire or sparks produced by the said pure magnetic apparatus, 

 requiring no galvanic batteries. 



POTTERY. 



Mr. Seely. — The art of pottery is the oldest of the arts. 

 4,000 years ago the tower of Babel was built, and it is said that 

 it was built of burnt brick. If clay is well dried, and does not 

 get wet it lasts a long time. A house on the river Nile built of 

 unburnt brick will last as long as a house built of burnt bricks 

 in this country. In Nineveh and Mesopotamia bricks have been 

 found in a good state of preservation with inscriptions on them. 

 The side of the bricks having the inscription on them was put 

 inside, and the plain side outside. No art has been brought to 

 such a state of perfection as pottery. It is no new thing for a 

 farmer in Western New York to plough up a piece of Indian 

 pottery. The ancient- pottery was quite rude, chemically consid- 

 ered, to what we make in these days. The Grecians manufac- 

 tured pottery which was equal to our best in regard to form, but 

 the ware was only equal to our poorest ware. They knew very 

 little about glazing. The first drinking vessels were made of 

 horn. 



The Chairman. — Drinking horns were in general use where I 

 lived during the revolution. 



Mr. Seely. — China ware is an invention of the Chinese, and 

 they claim that it was manufactured many years before the Chris- 

 tian era. It is only during the last century that they have suc- 

 ceeded in making it in England. Bethica was the first inventor 

 of it there. Clay, chemically, is composed of silicic acid and 

 alumina. Pure clay is silicate of alumina. Such a material as 

 this is not found in nature. Quartz is composed of felspar, 

 mica and quartz. 



The Chairman. — Is it not always found necessary to remove 

 some of the silica that is found in all clays before they are man- 

 ufactured ? 



Mr. Seely. — No ; silica is sometimes added. If you examine 

 a piece of porcelain with a microscope you will find that it is 

 composed of small particles covered with a glazing. Pure clay 

 is infusible ; alkali added makes it fusible. If you get too much 

 silex it will not be plastic enough. Take a lump of cast and a 

 lump of wrought iron and put them in a crucible and you cannot 

 melt them. The common notion is that fine clay is particularly 



