[Larger plate.]

[258]. Enclosed cone roller mill, with horizontal spindle and spirally grooved roller and casing.

[259]. Toothed sector mill.

[260]. Conical edge runner and pan.

[261]. Ordinary flour mill. The material is fed in the centre, passes between the stones, and falls out into the outer casing.

[262]. Rattle barrel, for cleaning and burnishing articles by mutual attrition; sand or emery is sometimes used to assist the process.

[263]. Ball and pan mill, for crushing ores, &c. The balls are carried round by a cross arm fixed to the central spindle.

[264]. Inclined ball and pan mill.

[265]. Oscillating mill.

[266]. Drum and roller revolving mill.