Some interest attaches to crystals of krennerite, since this mineral has apparently the same composition as calaverite, the crystalline development of which presents such peculiar features. After completing the study of crystals of the latter substance, the author naturally turned his attention to krennerite to ascertain whether any similar peculiarities were noticeable, but nothing abnormal could be detected.

Good crystals of krennerite are rare. The Mineral Collection of the British Museum has however a specimen from Nagyág, on which are dotted numerous small crystals possessing a large number of brilliant faces. This specimen was examined by Prof. H. A. Miers rather more than twelve years ago, and the measurements of one good crystal are recorded in this Magazine.