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.
The first modern flushable toilet was described in 1596 by Sir John Harington, an English courtier and the godson of Queen Elizabeth I. Haringtonâs device called for a 2-foot-deep oval bowl waterproofed with pitch, resin and wax and fed by water from an upstairs cistern.