1769, and in 1771 a plant for making green bottles was 
established in Philadelphia. In 1797, a window glass 
factory was built in Pittsburgh, by Maj. Isaac Craig and 
James O'Hara, heing probably the first factory in which 
coal was used as fuel, for as late as 1810 wood was used 
in all glass plants except those in or near Pittsburgh. In 
1808, Thomas Bakewell and Robert Page completed a 
flint glass house in this city, and they were the first who 
successfully made flint glass in the United States. Tt is 
recorded that pot clay was hauled by wagons to Pittsburgh 
from Burlington, N. J., pearl ash and red lead were brought 
‘rom Philadelphia, and saltpetre was hauled from the 
natural caves of Kentucky. The product of the Pitts- 
burgh glass factories early received the approbation of 
consumers. Cut glass equal to the best quality produced 
in Europe was made by Messrs. Bakewell and Page. At 
the Paris Exposition in 1867, the first prize was awarded 
to an exhibit of pressed glassware, made by the O'Hara 
Glass Works. The abundance of coal in the vicinity of 
Pittsburgh, caused Pittsburgh to become the center of the 
glass making industry of the United States more than a 
century ago, and inexhaustible deposits of glass-making 
sand in the vicinity helped to maintain this leading posi- 
sion. Later the application of natural gas to glass-making 
served to make the position of Pittsburgh in the glass- 
making industry more secure. Raw materials which enter 
into the composition of window glass are sand, known 
chemically as silica; limestone, or calcium carbonate; 
salt cake, or sodium sulphate; soda ash and nitrate of soda, 
and carbon, in the shape of anthracite coal. The supply 
of these ingredients is practically unlimited, with the 
exception of soda ash, the cost of which has increased to 
such an extent, that salt cake is used as a substitute. 
Pittsburgh has always been a leader in the glass indus- 
ory, and its future is brighter than ever. Fuel and raw 
materials are to be found in unlimited quantities within 
short distances. Great schools, such as the Carnegie 
Institute of Technology and the Mellon Institute, are 
devoting considerable time to research work for the benefit 
of the glass industry. What is needed, in addition, to