1886.] NEW YORK ACADEMY OF SCIENCES. 225 



Manganese trace 



Chromium trace 



Phosphorus .243 



Sulphur .012 



Chlorine trace 



Carbon .177 



Silica .092 



100.072 

 G. Asteriation in garnet. 



M. Babinet examined star garnets, and mentions (''Repertoire 

 ■d'Optique Modernc ") some with four and others with six brandies. 

 He says that star garnets with four branches are not rare, he him- 

 self having found from twenty to thirty such in from ten to 

 twelve hundred specimens, but that star garnets with six 

 branches are rare, but one of them being found in six thousand 

 specimens. The asteria or star garnets are filled with what he 

 calls filaments or fibres, which cause the asteriated reflections, but 

 he does not state positively what they are. Dr. Isaac Lea ("Pro- 

 ceedings of the Academy of Natural Science, "" Philadelphia, Feb. 

 16, 1869) said tliat in the examination of a thin fractured piece 

 of a large garnet from North Carolina, he was surprised to find 

 minute acicular crystals Avhich took two or three directions. 

 This induced him to examine more closely into the varieties of 

 .garnets which were accessible to him. He also examined 154 

 specimens of Bohemian polished garnets. He found 48 with 

 acicular crystals, and in the precious garnets from Green Creek, 

 Delaware County, Penn., he found, upon examination of uncut 

 crystals, that nearly 25 per cent were possessed of acicular crystals. 

 Some 40 specimens of Brazilian pyrope were very free from spots 

 or cavities, and not an acicular specimen was observed in any 

 one. Essonnite from near Wheeling, Delaware, and spinel 

 from Ceylon were examined, but no microscopic crystals were 

 observed. From the minuteness of these microscopic crystals in 

 the garnet. Dr. Lea says that it would be very difficult to ascer- 

 tain what they are, but suggests that they may prove to be rutile 

 (Figs. 3, 4, 5, 6, 7, 8 of plate 9, same Proceedings). The figures 

 usually show these crystals arranged in two or three directions, 

 and in Fig 14 two crystals are in part geniculated. 



Having examined several hundred carbuncle-shaped Indian 

 garnets, measuring from 12 mm. (4^ inch) to 39 mm. (1^ inches) 

 in length, the writer found almost the entire lot to be oj^aque 

 from the immense number of included minerals, especially acicu- 

 lar crystals. Ninety-one crystals in a hundred showed four 

 branches, and nine crystals in a hundred showed six branches. 

 Oareful examination in bright sunlight revealed the fact that if 



