It is important that you do not expel the air or the barium. The air is used to expand the walls of the colon for a more detailed look at the lining of your colon. After the barium and air is in, the technologist will take a series of X-rays of your colon. You will be asked to hold your breath and remain still during the picture. An imaging physician will review the images to make sure that they are sufficient to make a diagnosis. If they are not, more pictures may be taken.
However, it is not known how the builders got the huge wooden support columns into position. Unlike western architecture, in ancient Chinese wooden architecture, the wall only defined an enclosure, and did not form a load-bearing element. Buildings in China have been supported by wooden frames for as long as seven millennia.
A comprehensive archaeological survey, using advanced technologies, has concluded that the Ming walls measure 8,850 km (5,500 mi). This is made up of 6,259 km (3,889 mi) sections of actual wall, 359 km (223 mi) of trenches and 2,232 km (1,387 mi) of natural defensive barriers such as hills and rivers. Another archaeological survey found that the entire wall with all of its branches measure out to be 21,196 km (13,171 mi).