Heres a bit of a mystery. I picked up this old spool, but Im not sure how it was used. It has a bit of what looks like green chalk on the line, but it could just be grime. It has about 50 feet of line on it now. The hollow through the axle would most likely be for an awl - used to hold the spool in place while the line was drawn out. It has a great patina and looks like it was turned from maple. If it was a chalk line, how was the chalk applied? If it wasnt a chalk line, what was it? Any thoughts or ideas?