Writer's Centre: CSI Dictionary: C

Comparative microscope
Dual microscope that allows simultaneous viewing of two separate object, for purposes of comparison. The images that each scope produces are juxtaposed in the same field. When comparing cartridge casings, for example, a cartidge casing from a crime scene could be placed under one scope and the test fired cartridge casing from a suspected gun could be placed under the other scope. The microscope then produces hals an image of the casing on the right and half on the left. This is how toolmark and firearm comparisons are done.