Page:Popular Science Monthly Volume 42.djvu/611

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generator directly alongside of the melting chamber instead of at a distance. The coal is burned on the ordinary step-grate to carbon-monoxide gas which passes while still hot directly to the combustion area. At the bridge separating the generator from the melting chamber the gas mixes with the requisite amount of heated air, and, being itself hot, produces by its combustion a sufficiently intense heat to accomplish the perfect fusion of the batch. This proximity of the generator to the melting chamber obviates the great difficulty which had hitherto interfered with the use of gas as a fuel in glass-making—that is, the difficulty in obtaining a sufficiently high temperature. There are five of these tank furnaces at Glassboro, two at Salem, and one at Camden. This improvement is directly in line with local needs, since it has effected a saving of over fifty per cent in the cost of fuel. The expression is somewhat hackneyed, and unavoidably brings to mind the individual who was so delighted with a stove which saved fifty per cent that he proposed to buy two and so save a hundred per cent; but the reported saving in the case of the furnaces is the result of several years' experience and is quite authentic. Nor is this the only saving effected by the tank furnaces. They do away with the large expense of crucible pots and reduce the cost of repairs to a purely nominal sum.

No invention could have been more timely. In the face of the serious competition at Pittsburg, the New Jersey bottle industry, with its expensive fuel, would have fared but ill had it continued to melt its sand and lime and alkali in the old-time pot furnace. The tank furnace has served the industry in good stead. Within the past few months another important improvement has been introduced at Glassboro, in the substitution of crude petroleum for coal as fuel. Formerly its use was limited to the "glory-holes," where the mouths of the bottles were finished in an aureole of yellow flame. Now it serves also for melting the glass and annealing the ware. A large storage tank has been constructed, and it is believed that in a short time oil will entirely supersede the use of coal. A fourth chapter in the history of glass-making may soon have to be written in which petroleum figures as the dominant element. The Glassboro people, at least, are disposed to look upon its introduction as somewhat epoch-making.

At the present time the eyes of the bottle-making world are also turned toward New Jersey for another reason. Their glance centers upon Woodbury, for in that quiet village the destiny of the bottle-blower may be said to be on trial. The Ashley bottle-making machine has been set in operation to see if it can not do the work of human hands and lungs, and do it better and more economically. The machine was described before the British Association in 1889, when it was stated that bottles had been made by the