Volume 19, page 385, 1934

     Petrographers interested in the mounting of heavy and accessory minerals have had varying success with high index immersion media.¹ None developed to date have been entirely satisfactory.

     Attention should be called to several high index resins recently developed by Mr. J. T. Rooney, chemist, of Buffalo, New York. The writer has had the privilege to test these resins thoroughly and has found them to be clear and to possess good color. Once melted, the resins do not have to be cooked. They harden upon cooling much faster than Canada balsam, yet they will not crack. The resins can be obtained in the following indices: 1.60, 1.61, 1.62, 1.63, 1.64, and 1.65.

     Petrographers can purchase these resins from Mr. Rooney, at the following address: Inspection and Research Laboratories, 52 West Chippewa Street, Buffalo, New York.

     1 Martens, J. H. C., Piperine as an Immersion Medium in Sedimentary Petrography: Am. Min., vol. 17, No. 5, May, 1932.