24 SMITHSONIAN INSTITUTION 



obtained for exhibition in the ball of economic geology, as well as 

 band specimens of plagioclase, magnetite, and other associated 

 minerals. 



At the celebrated zinc mines at Franklin Furnace, N. J., a collec- 

 tion was made of various kinds of fluorescent minerals for use in an 

 exhibit now under preparation in the Museum. The writer had the 

 kind permission of the New Jersey Zinc Company not only to collect 

 the material but also to use the company's ultra-violet ray arcs, which 

 enabled him to select only those minerals of the highest and richest 

 fluorescence. Many specimens show two varieties of fluorescent min- 

 erals in the same sample and display more than ordinary beauty under 

 the ultra-violet light. From lush green the colors change with a vel- 

 vety softness through yellow, pink, red, and brown. Several of the 

 species are phosphorescent as well as fluorescent and glow like living 

 coals of fire even after the light has been turned off. 



In October, 1932, the writer experienced the thrill of being the first 

 to investigate a cave which had just recently been discovered at Mount 

 Etna, near Heaver Creek, Md. From the opening on the side of a hill 

 one descends by a short but strenuous journey into a large rotunda 

 with a dome some 20 feet high. In the middle of the dome hangs an 

 elaborate and massive stalactitic growth resembling a huge ornate 

 chandelier. Flanking this on either side hang curtainlike growths 

 which add charm to the whole setting. Three main passageways lead 

 off into the darkness, two of which leave the rotunda almost side by 

 side. These twin corridors are guarded by man-sized stalagmites re- 

 sembling ghosts with capes drawn to shield themselves from light in 

 this abyss of eternal darkness. Along the walls are row on row of 

 stalagmites, almost, it seems, standing at attention while the proces- 

 sion passes. From the ceiling hang stalactites of innumerable sizes and 

 forms. The descent becomes steeper and progress becomes more diffi- 

 cult, for the passageway has widened but the floor has become a for- 

 est of stalagmites of all sizes. The fore part of the cavern was strik- 

 ing, but this portion is splendid. Gleaming white stalactites covered 

 with drusy crystals of calcite hang among growths of rich brown 

 and yellow. Pillars, towers, fairy grottoes, steeples, castles, and polar 

 scenes are there for the lively imagination. Deposits of mushroom 

 growths and sparkling calcite enchant the eye. The passage is nar- 

 row but long, and every foot of the way is packed with something 

 new. Most curious of all are stalagmitic growths on the floor with con- 

 volutions that resemble those of a human brain. 



Permission was granted by the owner to take out a grotto at some 

 future date for exhibition in the National Museum. 



