The celebrated Dr. Johnson tells what glass really is, 
in one of his delightful papers in The Rambler, saying: 
“Who, when he first saw the sand and ashes by casual 
intenseness of heat melted into a metalline form, rugged 
with excrescences and clouded with impurities, would have 
imagined that in this shapeless lump lay concealed so many 
conveniences of life as would in time constitute a great part 
of the happiness of the world? Yet by some such for- 
tuitous liquifaction was mankind taught to procure a body 
at once in a high degree solid and transparent, which 
might admit the light of the sun and exclude the violence 
of the wind, which might extend the sight of the philosopher 
to new ranges of existence, and charm him at one time with 
the unbounded extent of the material creation, and at 
another with the endless subordination of animal life, and 
what is yet of more importance, might supply the decay 
of nature and succor old age with subsidiary sight. Thus 
was the first artificer of glass employed, though without 
his own knowledge or expectation. He was facilitating 
and prolonging the enjoyment of light, enlarging the ave- 
nues of science, and conferring the highest and most lasting 
pleasure. He was enabling the student to contemplate 
nature and the beauty to behold herself.” 
The Egyptians practiced glass blowing more than 4000 
years ago, while the invention of glass is sometimes ascribed 
to the Phoenicians. Glass found in the ruins of Mycenae 
show that the Greeks were familiar with the art of making 
glass at least 600 years before Christ. Pliny mentions 
Gaul (France) as one of the western countries practicing 
the art. Venice early became a famous glass producing 
center. There is documentary evidence of glass-making 
in that city in 1090, and for 500 years the city held a fore- 
most place in its manufacture. In comparatively modern 
times glass-making extended to other countries. It be- 
came established as an industry in the United States early 
in the 17th century. 
Pennsylvania has been a producer of glass from the 
early history of the colony, for William Penn wrote a letter 
in 1688, in which he alluded to glass works in his domain. 
A flint glass factory was established near Lancaster in