1. English, 1913.
Mica, its History, Production, and Utilization. London, D. Jaroslaw, 1913.

8°: 86 p., frontispiece (colored), 24 illus.

Very scarce. The text includes chapters on thehistory of use, physical and chemical properties, occurences, production and working, application, production statistics, and consumption. A bibliography and index are included.

Bibliographical references: BL [07107.g.49.]. • NUC.

2. German, 1913.
Der Glimmer. Eine monographische Studie. Berlin, Verlag von Jaroslaw's Erste Glimmerwaren-Fabrik, 1913.

8°: 91 p., illus. Very scarce.

Bibliographical references: NUC.