The hand of Steve Cohan.
Steve Cohan of Hot Rock Masonry http://www.hotrockmasonry.com/ is having his MSA students build a small traditional wood burning lime kiln.
He designed it on a very good drawing program called Google Sketchup
At the demonstration build Steve checks the details of his design regularly on his laptop.
Progress goes well throughout the day. The kiln is built with fire bricks and clay. It is designed to do one burn of limestone which is stacked in the main brick chamber as it is built and then is heated to about 800 degrees F. from two lower chambers feeding into the centre. They will make quick lime from the limestone and then slake it to make hot mud and plaster which are the traditional materials of masonry for the last two thousand years.
Here Steve is placing the pieces of limestone (which is essentially chunks of calcium carbonate) carefully in the kiln, so that the intense heat from the furnace can shoot up and around the rocks and produce a complete chemical reaction. This fitting of the stones so that there is space between them seems like the inverse of what we do when we are dry stone walling. The limestone has to be stacked with the least amount of contact between each of the rocks.