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.
Imagine a world without this invention! On December 19, 1899, J.B. Rhodes invented the water closet. Today, it is commonly known as the toilet or commode. Before this invention, many people were using outhouses. It wasnât until Rhodeâs invention that people could use the bathroom in their own homes. And speaking of toilets, Robert Shurney, another black inventor, designed the toilet used aboard the Skylab.