Glass Marbles

Combustion Boats are used in laboratories for chemical analysis. … The surface of porcelain combustion boats are glazed all over with the exception of outside bottom. The bottom of a combustion boat is generally flat that allows it to firmly placed on a planar surface.

Durham tubes are used in microbiology to detect production of gas by microorganisms. They are simply smaller test tubes inserted upside down in another test tube. This small tube is initially filled with the solution in which the microorganism is to be grown.