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.
On this day in 1732, Benjamin Franklin of Philadelphia first published Poor Richardâs Almanack. The book, filled with proverbs preaching industry and prudence, was published continuously for 25 years and became one of the most popular publications in colonial America, selling an average of 10,000 copies a year.