In this country, charcoal was at first used universally for smelting iron, anthracite coal being considered unfit for the purpose.  In 1820 an unsuccessful attempt to use it was made at Mauch Chunk.  In 1833, Frederick W. Geisenhainer of Schuylkill obtained a patent for the use of the hot blast with anthracite, and in 1835 produced the first iron made with this process.  In 1841, C.E.  Detmold adapted the consumption of the gases produced by the smelting to the use of anthracite; and since then it has become quite general, and has caused an almost incalculable saving to the community in the price of iron.

The view of the engines which pump the blast will give an idea of the immense power which the Phoenix company has at command.  Twice every day the furnace is tapped, and the stream of liquid iron flows out into moulds formed in the sand, making the iron into pigs—­so called from a fancied resemblance to the form of these animals.  This makes the first process, and in many smelting-establishments this is all that is done, the iron in this form being sold and entering into the general consumption.

The next process is “boiling,” which is a modification of “puddling,” and is generally used in the best iron-works in this country.  The process of puddling was invented by Henry Cort, an Englishman, and patented by him in 1783 and 1784 as a new process for “shingling, welding and manufacturing iron and steel into bars, plates and rods of purer quality and in larger quantity than heretofore, by a more effectual application of fire and machinery.”  For this invention Cort has been called “the father of the iron-trade of the British nation,” and it is estimated that his invention has, during this century, given employment to six millions of persons, and increased the wealth of Great Britain by three thousand millions of dollars.  In his experiments for perfecting his process Mr. Cort spent his fortune, and though it proved so valuable, he died poor, having been involved by the government in a lawsuit concerning his patent which beggared him.  Six years before his death, the government, as an acknowledgment of their wrong, granted him a yearly pension of a thousand dollars, and at his death this miserly recompense was reduced to his widow to six hundred and twenty-five dollars.

[Illustration:  Rotary squeezer.]

[Illustration:  Boiling-furnace.]

When iron is simply melted and run into any mould, its texture is granular, and it is so brittle as to be quite unreliable for any use requiring much tensile strength.  The process of puddling consisted in stirring the molten iron run out in a puddle, and had the effect of so changing its atomic arrangement as to render the process of rolling it more efficacious.  The process of boiling is considered an improvement upon this.  The boiling-furnace is an oven heated to an intense heat by a fire urged with a blast.  The cast-iron sides are double, and a constant circulation