The first commercial cupola in the United States was the Colliau cupola, which was introduced in 1874. This cupola was prefabricated insofar as possible and was built primarily as a commercial product. It was highly successful, being a fast and economical melting unit. When first introduced, it presented a number of improvements, such as a hot blast, and double rows of tuyeres. After the Colliau cupola, the Whiting cupola was developed. It is still sold by the company bearing the name of its inventor, John H. Whiting. In the 1880s, Whiting developed a cupola that employed two rows of tuyeres,. | Fig. 6 Straight-sided lined cupola introduced after the middle of the 19th century. The first commercial cupola in the United States was the Colliau cupola which was introduced in 1874. This cupola was prefabricated insofar as possible and was built primarily as a commercial product. It was highly successful being a fast and economical melting unit. When first introduced it presented a number of improvements such as a hot blast and double rows of tuyeres. After the Colliau cupola the Whiting cupola was developed. It is still sold by the company bearing the name of its inventor John H. Whiting. In the 1880s Whiting developed a cupola that employed two rows of tuyeres with the lower row arranged to form an annular air inlet that distributed the blast around the entire circumference of the furnace. The tuyeres could also be adjusted vertically for changes in classes of work type of fuel and cupola diameter. This cupola permitted the use of either coal or coke as a fuel and was equipped with a safety alarm and blast meter. The Whiting cupola with its standardized construction soon proved a boon to foundrymen and was widely accepted. Connellsville Coke The story of the cupola and cast iron in this period would not be complete without reference to the development of Connellsville coke. Coke was in general use in Europe in 1750 but because of the heavy timber resources of the United States it was not produced here until 1817. From that time until 1860 American foundrymen generally made coke for their own use after 1860 coke became a commercial product. Connellsville coke was first produced in 1841 at Connellsville Pennsylvania in beehive ovens. The product proved so popular that the demand for Connellsville coke remained high until 1914 when by product coke came into greater demand. The use of coke and bituminous coal was made possible by the introduction of the hot-blast furnace in 1828 by James B. Neilson of Scotland. At first the blast pipes ran through the furnace. .