Find out, from the table, the medium having the highest optical density. Also, find the medium with the lowest optical density. 

Material medium	Refractive index	Material medium	Refractive index
Air	$1.0003$	Crown glass	$1.52$
Ice	$1.31$	Canada Balsam	$1.53$
Water	$1.33$	Rock Salt	$1.54$
Alcohol	$1.36$	Carbon disulphide	$1.63$
Kerosene	$1.44$	Dense flint glass	$1.65$
Fused Quartz	$1.46$	Ruby	$1.71$
Turpentine oil	$1.47$	Sapphire	$1.77$
Benzene	$1.50$	Diamond	$2.42$