The actual envelope of the building is composed of weathering steel facing the structural frame, and pink granite wrapping vertical concrete elements, with large glass panes filling in the voids.
12.
Instead of the heavy internal bracing and heavy exterior masonry of, for example, the Empire State Building, the designers of the trade towers chose a light, glass-and-steel facing threaded by steel columns.
13.
An original limited artist edition of 250 was published in 1989 and was an oversized fine press slip-cased book with stainless steel faced boards and digital clock inset into the front cover.
14.
In July 1865, Andrew Carnegie became fascinated with the " Dodd process, " a new English method of welding steel facing to iron railroad rails, and despite Tom's misgivings he purchased the American patent for the process.
15.
It is soft and is used for cutting; its purpose is to prevent damaging the steel face of the anvil by conducting such operations there and so as not to damage the cutting edge of the chisel, many smiths shun this practice, as it will damage the anvil over time.
