NCJ Number
16264
Journal
NBS DIMENSION Volume: 59 Issue: 1 Dated: (JANUARY 1975) Pages: 8-9
Date Published
1975
Length
2 pages
Annotation
DESCRIPTION OF THE STANDARD REFERENCE MATERIAL (SRM), A TECHNIQUE DEVELOPED AT THE NATIONAL BUREAUS OF STANDARD TO ENABLE CRIMINALISTICS LABORATORIES TO MORE ACCURATELY AND PRECISELY CHARACTERIZE GLASS EVIDENCE.
Abstract
THE SRM IS USED FOR CALIBRATING REFRACTOMETERS (THE INSTRUMENTS USED TO CHARACTERIZE GLASS EVIDENCE) AND IS DESIGNED SPECIFICALLY FOR MAKING MEASUREMENTS ON AUTOMOBILE HEADLIGHT GLASS. THE SRM 1820, REFRACTIVE GLASS INDEX CONSISTS OF TWO RECTANGULAR GLASS SLABS WHICH ARE USED FOR CALIBRATION PURPOSES IN THE 'IMMERSION METHOD' OF CHARACTERIZING GLASS. A POLISHED SLAB IS USED TO CHECK THE PERFORMANCE OF REFRACTOMETERS, AND AN UNPOLISHED SLAB, WHICH CAN BE BROKEN INTO FRAGMENTS, IS INTENDED FOR MICROSCOPIC DETERMINATION OF THE REFRACTIVE INDEXES OF IMMERSION LIQUIDS. 'CLASSIFYING' GLASS EVIDENCE ENTAILS DISTINGUISHING THE AUTOMOBILE HEADLIGHT GLASS FROM OTHER TYPES OF GLASS. 'INDIVIDUALIZING' EVIDENCE INVOLVES IDENTIFYING THE EVIDENCE AS COMING FROM A SPECIFIC, SUSPECT AUTOMOBILE. THE USE OF THE SRM AND THE IMMERSION METHOD IN BOTH PROCESSES IS DESCRIBED.