furnaces to cool off after being heated for melting. When the fires cool
down, and before they are started up again, the furnaces now using
coal will doubtless all be changed so as to admit natural gas. The
superiority of French over American glass is said to be due to the fact
that the French use wood and the Americans coal in their furnaces, wood
being free from sulphur, phosphorus, etc. The substitution of gas for
coal, while not increasing the cost, improves the quality of American
glass, making it as nearly perfect as possible.

While the gas is not used as yet in any smelting furnace nor in the
Bessemer converters, it is preferred in open hearth and crucible steel
furnaces, and is said to be vastly superior to coal for puddling. The
charge of a puddling furnace, consisting of 500 pounds of pig-metal and
eighty pounds of "fix," produces with coal fuel 490 to 500 pounds of
iron. With gas for fuel, it is claimed that the same charge will yield
520 to 530 pounds of iron. In an iron mill of thirty furnaces, running
eight heats each for twenty-four hours, this would make a difference in
favor of the gas of, say, 8 x 30 x 25 = 6,000 pounds of iron per day.
This is an important item of itself, leaving out the cost of firing with
coal and hauling ashes.

For generating steam in large establishments, one man will attend
a battery of twelve or twenty boilers, using gas as fuel, keep the
pressure uniform, and have the fire room clean as a parlor. For burning
brick and earthenware, gas offers the double advantage of freedom from
smoke and a uniform heat. The use of gas in public bakeries promises the
abolition of the ash-box and its accumulation of miscellaneous filth,
which is said to often impregnate the "sponge" with impurities.

In short, the advantages of natural gas as a fuel are so obvious to