II. MINERALS, ETC. 753 



399. Cerussite. Riddersk, Altai. 



400. Taininsk, Nertchinsk. 



401. Cerussite. Kadamsk,"N"ertchinsk. 



406. Malachite. Beloussovsk, Altai. 



407. Aurichalcite. Zavodinsk, Altai. 



408. Azurite. Nikolaievsk, Altai, 



409. Semenovsk, 



410. Zyrianovsk, 



402. Cerussite. Ildikensk,Nertchinsk. 



403. Witherite. Zmeinogorsk, Altai. 



404. Malachite. Gumeshevsk, Ural. I 411, 412. Mellite. Male vka, Tula. 



405. Malachite. Nishni, Tagilsk,Ural. j 



3470. I. Sphere of Calcite, 3 J inches in diameter. 



II. Polyhedron of Calcite, cut from a large rhombohedron 

 of that mineral, so as to represent the optical characters of the 

 crystal in directions perpendicular, 



1. To the pinakoid, and along the optic axis. 



2. To a prism plane, and perpendicular to the optic axis. 



3. To the cleavage planes (of the rhombohedron) (100). 



4. To the plane (122) correktive to the cleavage rhombohedron. 

 (These were made by Mr. Ahnens.) P^of. W* S. Maskelync. 



3471. Collection of Crystals of Minerals. J.R. Gregory. 



3472. Nicol's Prism, whose side is about 60 millimeters. 



Wilhelm Steeg, Hamburg. 



3473. Prism of Bock Salt, 50 x 60 mm. 



W. Steeg, Homburg vor der Hdhe. 



3474. Lens of Bock Salt, 75 mm. thick, and 300 mm. in 

 radius. W. Steeg, Homburg vor der Hdhe. 



3475. Plate of Bock Salt, 60x60 torn. 



W". Stceg, Homburg vor der Hdhe. 



3476. Calcspar Bhombohedron, with glasses ground parallel 

 and perpendicular to the axis. Wilhelm Steeg, Homburg. 



3477. Calcspar Prism, with plane parallel to the axis. 



Wilhelm Steeg, Homburg. 



3478. Piece of Sulphur with large Crystals. 



Prof. A. MitscJierlich, Miinden, Hanover. 



E. Mitscherlich by these crystals of sulphur determined the crystalline form 

 of the sulphur from the molten condition, and discovered the dimorphism of 

 sulphur. 



b. MODELS AND DIAGRAMS OF CRYSTALS, ROCKS, MINERALS, &c. 



3479. Diagrams and Microscopic Slides, demonstrat- 

 ing the structure of Bohemian Basalt. 



1. Diagram representing the most important types of Bohemian 

 Basalt. On six plates. 



2. Diagram showing the most important types of Phonolite, 

 Trachybasalt, Trachylitbasalt, and Melaphyr rocks. On four plates. 



3. Two boxes containing 10 microscopical preparations of the 

 above-mentioned rocks. 



4. Professor Boricky's works on the Basaltic and Phouolithic 

 rocks of Bohemia, with short explanation of the Melaphyr 

 illustrations. Dr. Emanuel Borricky, Prague. 



39508. 3 B 



