Historical Scientific Instrument Diagram - Tapered Rod with Labeled Sections #3065016 (License: Personal Use)

This black-and-white technical illustration depicts a precision-tapered rod, possibly part of a thermometer, refractometer, or calibration tool from the late 19th or early 20th century. Section 'a' shows a narrow mid-section with fine concentric grooves, 'b' is the wider base with coarser banding, and 'c' is the smooth upper cap-suggesting functional segmentation for measurement or assembly. The style reflects engraving techniques used in scientific journals and instrument manuals of the era.

Used in educational, archival, or museum web pages discussing historical scientific instrumentation; supports user intent to identify, research, or replicate antique lab equipment.