1890.] NEW YORK ACADEMY OF SCIENCES. 149 



of boulders of jade sawn by M. Alibert from blocks found by 

 himself; these were beautifully polished on both sides, were less 

 than one-eighth inch in thickness, and some measured three feet 

 in length and over eighteen inches in width, forming beautiful 

 panes for windows, having a delicate shading and a brilliancy not 

 to be obtained in any other material. With this was a large 

 series of graphite, curiously carved into ornaments, to show the 

 perfect homogeneity and fine grain of the graphite from his 

 mines. 



The collection of Mr. Woerfel contained a large number of the 

 table-tops, mantels, vases, and other ornaments of malachite, lapis- 

 lazuli, rhodonite, Labrador spar, and other stones characteristi- 

 cally Russian, which have been used extensively in that country 

 in the decoration of churches and palaces, and have been fre- 

 quently made use of as imperial gifts by the Czar, as the royal 

 palaces throughout Europe will testify. 



From the Ural Mountains came an exhibit of a magnificent 

 series of blue, white, and sherry-colored topaz crystals, some of 

 the largest of which weighed one pound, and some smaller one?, 

 several inches in length, were absolutely transparent ; a doubly 

 terminated crystal of beryl that weighed one pound eight 

 ounces, but was not entirely free from internal fractures ; small 

 crystals of alexandrite; some magnificent puiple amethysts, un- 

 rivalled for depth and richness of color; a chrome tourmaline in 

 crystals from one to three inches in length, and other varieties 

 of well-known Eussian minerals. 



Paul de KristofEowitch exhibited a very interesting material, 

 termed by him pyrogranit, for which he has secured patent 

 rights in many countries. It is obtained by vitrifying slates 

 and shales, and it imitates closely many varieties of marble, por- 

 phyry, and granite, having almost the hardness of the latter, 

 and being susceptible of a high polish. It was shown as bath- 

 tubs, tiles, and ornamental pieces, and is undoubtedly the most 

 satisfactory of the artificial stones that have been produced. 



The Russian Society for the Mining of Mercury, formed by 

 Dr. Auerbach, the chemist, made a splendid exhibit of the ores 

 and of native mercury from their mine. This mine was discov- 

 ered by M. Minenkoff in 1879, but no development was at- 

 tempted until 1886. The mine and the works are in Central 

 Russia, in the jurisdiction of Ekatherinoslaw, Bakmouth District, 

 four kilometres east of the station Nikitowa on the Koursk- 

 Karkoff-Azof Railroad. Besides the surface of cinnabar, cov- 

 ered with brilliant crystals, of special interest to the mineral- 

 ogist were the quantities of perfectly detached crystals and 

 penetration rhombohedral twins of cinnabar, which are quite 

 unique ; they measure from two to three millimetres across a 

 face. 



