Thursday, January 17, 2013

crystallography

 
"Fig. 102 shows a tetrahedron (o), it's edges bevelled by the trigonal tristetrahedron, +202/2, k{211} (l), and its angles replaced by the rhombic dodecahedron (d)."

From the 1890 edition of Elements of Crystallography by George Huntington Williams.  Fig. 102. appears in the chapter "The Isometric System".

Saturday, January 12, 2013