OF ARTS AND SCIENCES. 



165 



Angles between Hormals. 



OTl 

 OTl 

 OTl 

 TTO 

 TTO 

 TOl 

 TIO 



001 

 001 

 001 



001 



Found. 



TTO 

 TOl 

 Oil 

 TOl 

 TIO 

 TIO 

 OIT 



TIO : Oil 

 001 : TTO 



TIO 

 OTl 

 Oil 

 TOl 



. 47° 15' 1 

 G9° 50' 



135° 27' 

 34° 18' 

 76° 57' 

 48° 49' 

 61° 14' 

 58° 6' 

 73° 59' 

 93° 8' 

 54° 6' 

 81° 21' 

 63° 37' 



Calculated. 



^ Fundamental anjiles. 



48° 58' 

 61° 12* 

 57° 41' 

 74° 18' 

 93° 41' 

 53° 49' 

 81° 38' 

 63° 57' 



Bromine when moderately diluted with carbonic disulphide has no 

 further action upon this substance. It is attacked, liowever, when 

 exposed to the vapors of bromine, and deliquesces rapidly, forming a 

 dark-red syrup, which over lime in vacuo gradually solidifies. From 

 this product I have as yet been unable to isolate any substance with 

 characters sufficiently well marked to encourage further study. 



Dihrompyroxanthin, CjgHjgBrjOg. The subtraction of bromine, on 

 the other hand, gave a beautifully crystalline product with sharply 

 marked characteristics. This substance I first made by the action of 

 phenol. If the dibrompyroxanthintetrabromide is gently warmed 

 with a little phenol, to which sufficient water has been added to keep 

 it liquid, it dissolves, forming a highly colored solution, which is red 

 by transmitted and green by reflected light. If alcohol is then 

 added, it causes the separation of an abundance of fine, felted 

 brilliant-yellow needles, which may be recrystallized from alcohol. 

 This same substance may also be made by boiling the tetrabromide 

 with absolute alcohol, and adding zinc dust or finely powdered metallic 

 antimony. The latter method is perhaps most advantageous, since 

 little or no product is obtained if the phenol solution is too strongly 

 heated, or, if the zinc dust contains a large percentage of oxide. 

 For analysis, the substance was dried at 100° after several recrystal- 

 lizations from alcohol. The material used in analyses L and II. was 

 made with phenol, while that used in analysis III. was made with 

 antimony. 



