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.
In time the printed book became a means of political revolution, the necessary technological corollary for the rise of the vernacular (ie. non-Latin) as a vehicle for literary texts, and the larger democratic revolutions of the eighteenth century. In 1814, The Times of London introduced the first steam-press.