Ice Age 



A glacial epoch in which glaciers and ice sheets occupied 

 large areas of continents, as occurred in the Quaternary 

 period. 



Ichthyology 



The branch of zoology which deals with fishes. 



Ideograph 



A pictorial diagram of an object in which relationships 

 are shown between measurements of various characteristics. 



Idiobiology 



The study of the individual organism, cf. Autecology, 

 Synecology, Individual ecology. 



Illuminance 



Syn. Light intensity. A unit of illuminance is the lumen 

 per square foot, equivalent to the foot-candle when Light 

 intensity is used. cf. Illumination value. 



Illumination Value 



The illumination capacity or brightness of light as per- 



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