Introduction

In Syria there is a region known as Phœnice,

adjoining Judæa,… in this district …near the colony

of Ptolemaïs [Acre] …for many ages, this was the

only spot that afforded the material for making

glass. The story is, that a ship, laden with nitrum,

being moored upon this spot, the merchants, while

preparing their repast upon the sea-shore, finding no

stones at hand for supporting their cauldrons,

employed for the purpose some lumps of nitrum,

which they had taken from the vessel. Upon its being

subjected to the action of the fire, in combination

with the sand of the sea-shore, they beheld

transparent streams flowing forth of a liquid

hitherto unknown: this, it is said, was the origin of

glass.

(Pliny the Elder, Natural History, XXXVI, Chapter

65).

This is how the Roman author, the Elder Pliny, explains the invention of glass in his Natural History, written in the

second half of the first century CE. However, we now know that this remarkable man-made substance was first

manufactured further east, in Mesopotamia and that this happened some 2,500 years before Pliny's time, in the middle

of the third millennium BCE.

Pliny's account nonetheless gives the three principal ingredients of raw glass in antiquity, namely soda, silica and lime.

Nitrum, (or natron, as it is actually called today) is a naturally occurring soda; sand was the silica, and this probably

contained lime, the third necessary element. The composition of naturally occurring glass is 72% silica, 15% soda, 10%

lime and 3% impurities. Pliny also correctly identified the basic component as the "sand of the sea-shore" for beach

sand, the main ingredient in glass, contains silica and lime, the latter component coming from crushed shells. However,

the heat from a cooking fire would never reach the desired temperature for full fusion of glass. Temperatures of circa

1150 degrees are needed to transform the raw glass into fluid glass.