Additional information about Agate can be ob- 
tained from the following works: 
Liesegang, Raphael Ed.— Die Achate. Theodor Steinkopf, 
Dresden and Leipzig, 1915. 118 pp. 
Dreher, 0.— Das Farben des Achates. E. Kessler, Idar, 1913. 
Bauer, Max. — Precious Stones. Translated with additions by 
L. J. Spencer. Griffin and Company, Ltd. London, 
1904. 627 pp. 
Kunz, George F. — Gems and Precious Stones of North America. 
Scientific Publishing Company, New York, 1890. 336 pp. 
The Magic of Jewels and Charms. J. B. Lippincott Co., 
Philadelphia. 1915. 422 pp. 
20 pp. 
[140] 
