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.
The oldest complete printed and dated book is a Buddhist text known as the Diamond Sutra, a name apparently suggested by the Buddha himself, as the text is designed to âcut like a diamond blade through worldly illusion to illuminate what is real and everlasting.â