1886.] NEW YORK ACADEMY OF SCIENCES. 11 



of tlie furnace. Breaking tlie crucible, they found a superficial 

 vitreous layer of silicate of lead, and underneath a mass of co- 

 rundum crystals grouped in magnificent geodes. By the addi- 

 tion of a little bichromate of i)otash rubies were obtained, and 

 sap)ihires by the further addition of a little oxide of cobalt. 

 These are the most beautiful crystals of ruby and sapphire that 

 have ever been obtained, but their hexagonal tabular form unfits 

 them for cutting. They have the ])i-operties of corundum; 

 D=:4.0 to 4.1. The rubies, like uatural stones, were tempora- 

 rily decolorized by heating. MM. Fremy and Feil have also 

 added fluoride of barium to the aluminate of lead in the preced- 

 ing experiment. The two reagents were mixed in equal parts 

 with the addition of a little bichromate of potash, and heated in 

 a siliceous crucible surmounted by another reversible crucible. 

 In the lower crucible they obtained a geode of ruby with vitre- 

 ous inclusions, while the upper one was lined with long needles 

 of a silicate of alumina and baryta. According to the analysis 

 of L. M. Ferreil, this product is probably a barium anorthite. 



MM. Fremy and Feil endeavored to retard the reactions in 

 this experiment so as to increase the size of the crystals. M. 

 Stanislas Meunier (C. E., 1880, t. XC, p. 701), decomposed in 

 a red-hot tube chloride of aluminum by the use of steam. In 

 several experiments magnesium or zinc were also used as re- 

 agents. Corundum was thus produced in hexagonal plates or 

 crystalline grains. MM. Fouque and Michael Levy accidentally 

 observed the formation of corundum in beautiful hexagonal 

 plates while they were fusing microcline feldspar with fliiorite. 

 The corundum by sublimation lined the j)latinum cover of the 

 crucible in which the experiment was made. 



Last of all, M. F. Parmentier (C. E., 1882, t. XCIV.. p. 1713), 

 in a work relative to the action of molybdates upon oxides by 

 dry prncess, has announced that the fusion of amorphous ;ilu- 

 mina with bimolybdate of potash will furnish corutulum in i>hites 

 like tridymite. It is important to keep the temjierature of the 

 crucible high, for if it is lowered an inverse reaction takes place. 



Dr. T. Sterry Hunt remarked upon the character of these 

 artificial rubies, and upon the artificial jiroduction of minerals 

 in general, and compared their properties with those of the nat- 

 ural minerals. 



President Newberry announced the death of Mrs. Ermin- 

 NiE A. Smith, which occurred June 9, 1886. Prof. D. S. 

 Martin, Mr. George F. Kunz, and Mr. B. B. Chamberlin were 

 appointed a committee to prepare memorial resolutions. 



