Each cross bar or row of holes in the roll controls a row of the pattern and mechanically determines which warp yarns (harnesses) will be raised and which lowered.
The commencing height and the plan of raising the cross bar will be as follows.
So tall was he that his hat actually brushed the cross bar of the doorway, and his breadth seemed to span it across from side to side.
"Oh all right" he said with a laugh one morning and moved the narrow white cross bar higher.
