A one-page installment of Samuel S. Dale's series on "straight line" textile calculations. It lists equivalent expressions for the fixed-weight yarn numbering systems (run, cotton, worsted, linen, woolen, metric), and explains yards per ounce, the denier count and dram system for silk, and the jute pound system. It also shows how to convert yarn numbers between systems and includes a table of reeled silk diameters by denier, in microns and diameters per inch.