Comparison Microscope

A comparison microscope is a device used to analyze specimens, side-by-side. It is sometimes known also as stereo microscope or dissecting microscope. This device consists of two microscopes connected to an optical bridge. Such design results to a split view window.

The comparison microscope is used in forensic sciences for comparison of microscopic patterns and for identification or negation of their common origin.

The principle behind this microscope is simple. Two microscopes are placed next to each other. The optical paths of each microscope are connected together by the optical bridge. Such set-up would help the forensic examiners to compare two specimens simultaneously instead of just depending on human memory.

The history of comparison microscope could be traced back to the 1920s. In this time, forensic ballistics was waiting for its commencement. It sprang from the controversial case of accused murderers and anarchists Nicola Sacco and Bartolomeo Vanzetti in 1921. The said microscope was used for ballistic identification of evidence to help secure convictions of the accused murderers, Sacco and Vanzetti. With the use of such microscope in 1929, Calvin Goddard and his partner Phillip Gravelle used similar techniques to acquit the Chicago Police Department from the accusation of participating in the St. Valentine’s Day Massacre.