Published Online: 1 July 1980
Page Count: 12
Director, New York City Crime Laboratory,
Criminalist, New York City Police Department,
Associate professor of criminalistics, John Jay College of Criminal Justice, New York City,
(Received 19 October 1979; accepted 26 November 1979)
This paper describes a refined approach to the problems of identification and comparison of synthetic fibers encountered in forensic science case work. The necessary apparatus consists of a polarizing microscope equipped with a Mettler hot stage. Observations concerning the variation of a fiber's birefringence with temperature have been found to be very useful, both for determining the generic type of an unknown fiber and for detecting subtle differences among fibers of the same generic type from different sources. Data, including semilogarithmic plots of birefringence as a function of temperature, are given for nine different generic types of synthetic fibers.
Paper ID: JFS11259J