For example, for the Gases under pressure hazard class, the hazard categories are Compressed gas, Liquefied gas, Refrigerated liquefied gas and Dissolved gas. These classes relate to the physical state of the gas when packaged and do not describe the degree of hazard.
1 In 1596, a flush toilet was invented and built for Queen Elizabeth I by her Godson, Sir John Harrington. 2  The first patent for the flushing toilet was issued to Alexander Cummings in 1775. 3  During the 1800s, people realized that poor sanitary conditions caused diseases.
Why did Sir John Harington invent the toilet? The writer John Harington (or Harrington, 1561-1612) designed the flush toilet called the Ajax in 1596, in an effort to replace the system of chamberpots (which had to be move â¦ d by servants to far from the bedchambers after use).