The Storv of Pittsburgh 
Clay Products 
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HE uses of clay are numerous, and the history of the 
human race shows that very early extended use was 
made of this substance. Bible readers are familiar 
with the way in which Pharoah embittered the slavery of 
the children of Israel by compelling them to find their own 
straw for the brick they were required to make. 
The clay industry probably had its beginning in the 
Valley of the Euphrates, which is the traditional cradle of 
the human family. According to some authorities, brick 
dating back to 4500 B. C. have been found in Babylonian 
excavations. Early man noticed how the heat of the sun 
hardened the mud along the banks of the river, cracking 
it into irregular pieces which could be utilized, after shaping 
them to the desired size, in erecting the walls of his rude 
hut. Then naturally came the next step, which was to 
give the mud the proper shape while it was yet soft and 
plastic, and lay it out in the hot sun to bake. This pro- 
duces what is called “adobe” brick, and the next improve- 
ment was to make the baked bricks more solid by mixing 
chopped reeds or straw with the soft mud before shaping 
and baking. 
Artificial burning of the shaped clay came later. The 
Tower of Babel is supposed to have been built of burned 
brick. By the time Nebuchadnezzar came to the throne 
of Babylon, in the sixth century before Christ, not only 
had brick making become an art, but a decorative art 
also, for colored enamels were used with fine effect for 
decorative purposes. The old Romans were great builders 
of dwellings and aqueducts, and although they used much 
stone in their work, they also used huge quantities of brick. 
After the Roman empire disintegrated, and the nations of