An Encyclopedia of the History of Technology part 19. This one of a kind encyclopedia presents the entire field of technology from rudimentary agricultural tools to communication satellites in this first of its kind reference source. Following an introduction that discusses basic tools, devices, and mechanisms, the chapters are grouped into five parts that provide detailed information on materials, power and engineering, transportation, communication and calculation, and technology and society, revealing how different technologies have together evolved to produce enormous changes in the course of history | PART ONE MATERIALS for all practical purposes Hall s process quite quickly became the standard one as long as wrought iron was made. In Cort s process he used atmospheric air as a decarburizing agent and ignored the other chemical reactions in his furnace chemistry like other sciences was far from advanced at that time. The amount of oxygen available for decarburization was limited so the process had to be slow and the longer it took the more fuel would be needed. Much worse however was the inefficiency of the process for every tonne of wrought iron made about two tonnes of pig iron were needed. When the pig iron was brought up to melting point some of it formed magnetic oxide Fe3 O4 which made slag with the silica in the sand lining of the furnace. This was the source of the waste about half of all the pig iron went away with the slag. Hall s wet puddling used the same reverberatory furnace as Cort but a flux was added with the iron which helped the chemical reaction by providing a better source of oxygen than could be provided by air alone and made the whole process much more efficient. The reaction was a violent one with the iron at one stage literally boiling at his first trial Hall was alarmed and thought the whole furnace would be destroyed. But after a short time the boiling stopped and the iron when taken out was found to be excellent. Hall started his own works to use the new idea and his iron became famous for its high quality. Others followed and before long the old Cort process was dropped by most ironmakers in favour of Hall s process known from what happened at one stage as pig boiling . The man responsible for improving the blast furnace was not an ironmaker but the manager of Glasgow gasworks who put his idea to work in 1828. Before that date the air for the blast furnace was blown in at its natural temperature Neilson tried heating the air before it was blown into the furnace. In fact the current general theory was that the colder the .
