Graphology - the study of handwritings; autograph - written with one's own hand; seismograph - a machine noting strength and duration of earthquakes. marina - a harbor for pleasure boats; maritime - relating to the sea; submarine - an undersea boat; aquamarine - color of sea water.
Chemicals are classified into various hazard classifications in accordance with their physiochemical properties and health hazards. Each class of chemical has a pictorial symbol called a danger symbol.
1 Class 3: Flammable liquids. 2  Class 4: Flammable solids. 3  Class 5: Oxidizing agents and organic peroxides. 4  Class 6: Toxic and infectious substances. 5  Class 7: Radioactive substances. 6  Class 8: Corrosive substances. 7  Class 9: Miscellaneous.