quartz specimens with left and right Airy's spirals
Date: 1850-1870
Inventory Number: 2007-1-0529
Classification: Polarization Specimens
Subject:
Maker: William Ladd ? (fl. 1839 - 1872)
Maker: German ?
Maker: French ?
User: Harvard College Observatory (founded 1839)
Associate Name: Sir George Biddell Airy (1801 - 1892)
Cultural Region:
Place of Origin:
Dimensions:
each slide: 0.4 x 3.5 x 3.5 cm (3/16 x 1 3/8 x 1 3/8 in.)
Description:
This is a pair of quartz samples mounted in cork slides. The slides are square and covered with paper labels. The names are written by hand in ink on the labels, indicating quartz with left and right polarity.
The edges of the cork slides are taped with paper printed with "HARVARD COLLEGE OBSERVATORY."
Both slides are marked in pencil, "B. 17. Airys Spirals / Ladd."
The edges of the cork slides are taped with paper printed with "HARVARD COLLEGE OBSERVATORY."
Both slides are marked in pencil, "B. 17. Airys Spirals / Ladd."
Signedprinted on paper: HARVARD COLLEGE OBSERVATORY
in pencil on each slide: Ladd
in pencil on each slide: Ladd
InscribedBoth slides are marked in pencil: B. 17. Airys Spirals
FunctionQuartz has a crystal structure that spirals either to the left or to the right along the direction of the optic axis. If viewed with a conoscope (a strain free acrylic or glass sphere on a rod), one sees a "bull's-eye." With the addition of a quarter wave plate, the bull's-eye becomes two spirals, which spiral either to the left or right, showing their left-handedness or right-handedness. These spirals are named Airy Spirals after Sir George Biddell Airy who first described the phenomenon in 1831.
ProvenanceHarvard College Optics Lab; transferred to CHSI, 10/19/1967