The Project Gutenberg eBook of Crystals
Title: Crystals
Author: A. E. H. Tutton
Release date: July 15, 2022 [eBook #68530]
Language: English
Original publication: United Kingdom: K. Paul, Trench, Trübner, 1911
Credits: Richard Tonsing and the Online Distributed Proofreading Team at https://www.pgdp.net (This file was produced from images generously made available by The Internet Archive)
Transcriber’s Note:
The cover image was created by the transcriber and is placed in the public domain.
Fig. 90.—Screen Picture in Polarised Light, with Nicols crossed, of a thick Plate perpendicular to the Axis of a naturally twinned Crystal of Quartz, the left half being of right-handed Quartz and the right half of alternately left and right-handed Quartz, the Planes of Demarcation being oblique to the Plate.
Fig. 97.—Crystals of Benzoic Acid in the Act of Growth, as seen on the Screen in Polarised Light with crossed Nicols.