First, the extinguisher valve is removed and the threads and interior of the cylinder are checked for corrosion, pitting, and any other abnormalities. [29 CFR 1910.157(f)(3)] If the cylinder passes the visual inspection, it is placed into a steel chamber, which is then filled with water at normal pressure.
Updated April 17, 2017. The earliest dated printed book known is the Diamond Sutra, printed in China in 868 CE. However, it is suspected that book printing may have occurred long before this date. In 1041, movable clay type was first invented in China.
Today, we print books in a wilderness. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them. In 1638, Mrs. Glover set up America's first press at the Massachusetts Colony's new college, Harvard. Mrs. Glover and her husband, the Rev. Jose Glover, had sailed from England with five children, a few technicians, and a printing press.