The Two-Pulley Clothesline: Let the Washing Pass the End

"The invention consists in an arrangement whereby on one end of the line two blocks or pulleys are used, allowing the clothes to pass between them, and thus allowing the whole rope or line to be used for hanging clothes on, instead of the present method, whereby only one-half of the line can be used for that purpose." "A is the large pulley over which the clothes-line or rope passes. B is the small pulley, revolving in an opposite direction from the large pulley; the lower circle of the two pulleys touch, and are covered by two India-rubber bands or rings, D D, which permit the clothes to pass through without injury to them." "The reason for two pulleys is to prevent the clothes-line from coming off."

Tie a clothesline between two firm points about 3 m apart, with a force meter in the line at one end. Peg equal weights (filled water bottles work) at equal spacing along it. Measure the sag at the middle with the ruler and read the pull on the force meter. Tighten the line to halve the sag and read again. Put your span, weight per metre and sag into the notebook's formula and compare with the force meter.

**George H. Ryer** of New York filed US 139,024 on 24 October 1872; it is dated 20 May 1873. **Honest limits.** The tension formula assumes an evenly loaded line with a small sag; bunched washing pulls harder. The span, load and sags are examples. Your force-meter readings are the measurement.