NIELLARE: to work in niello, of which the various processes are described in Tra., Ch. I.
NOCCIOLO: the ‘kernel,’ or the framework of clay or iron that fits into a casting, and tallies in its various parts with the lasagna or coating of the mould. Tra. 173, 183.
NOTTOLINO: any little knot or tie of metal in jewellery. Tra. 94.
OCCHIO DI GATTA: the cats’ eye stone. Tra. 43.
OLIO DI GRANA: linseed oil. Tra. 58. OLIO DI MANDORLE: almond oil. Tra. 59. OLIO D’OLIVA: olive oil. Tra. 59.
ORIVUOLO: a clock. Tra. 11.
ORLO: a ridge or mound of wax, e.g., round the copper etching plate. Tra. 155.
ORO MATTO: dull gilding. Tra. 210.
OSSATURA: the framework or sketch upon which the various portions of a colossus are pieced. Tra. 209.
OTTAVO: a species of silver solder formed of one-eighth part of an ounce of copper to one ounce of silver. Tra. 143.