20 



MINERALOGY. 



In Charge of Edmund O. Hovey. 



1. Petrographic Instruments. Exhibited by the inventor, 



Dr. T. A. Jaggar, Jr., Harvard University. 



a. Microsclerometer, for determining exactly the hardness 

 of minerals under the microscope. 



h. Instrument for inclining a preparation in the petro- 

 graphic microscope. 



2. Models and Apparatus recently acquired by the Mineral- 



ogical Department, Columbia University, and exhibited 

 by Prof. A. J. Moses. 



a. Student Goniometer designed by Prof. P. Groth. 



b. Model of Spherical Projection, Isometric Crystal, 



c. Model of Spherical Projection, Triclinic Crystal. 



d. Model of Positive Uniaxial Ray Surface. 



e. Model of Negative Uniaxial Ray Surface. 

 f. Model of Biaxial Ray Surface. 



3. Exhibit of Prof. J. F. Kemp, Columbia University. 



a. Chalcanthite, Mt. Wilson, San Miguel County, Colo, 

 Collected by M. B. Spaulding. 



b. Calaverite (?), inclosing Native Gold, Kalgoorlie, Wes- 

 tralia. Collected by G. J. Bancroft. 



4. Exhibit of the Department of Mineralogy, American 



Museum Natural History, through L. P. Gratacap, 



a. Endlichite, Hillsboro, New Mexico. 



b. Pollucite, Paris, Maine. 



c. Hamlinite, Paris, Maine. 



d. Montmorillonite, Paris, Maine. 



e. Beryl, containing Ccesium, Haddam Neck, Conn. 

 f. Microcline, Haddam Neck, Conn. 



