The Hammock: A Slack Rope, a Swing and the Pull on the Anchors

"My invention relates to improvements in hammocks, and it has for its object to provide a novel arrangement of the ropes supporting the body of the hammock whereby a vibratory movement may be easily obtained and regulated as desired, and wherein a person may recline at ease, with the body in a straight and natural position". "The vibratory motion of a weight supported by a slack rope or wire depends, first, upon the amount of power applied thereto; second, upon the position upon the rope where the weight is attached; third, upon the distance of the weight from the slack rope if suspended therefrom." A weight "would take and sustain a longer vibratory motion, with the same power, if distant from the slack rope than it would if but slightly removed therefrom". "A single rope, wire or cable B is attached at its ends to suitable uprights or supports C, such as a house and tree as shown in Fig. 1 or posts suitably secured in the ground as shown in Fig. 2, and said rope B is of such length as to have sufficient slack to answer the purpose of my invention."

Tie a cord between two fixed points about 1.5 m apart, one end through a spring scale so you can read the tension. Hang a known weight (a bucket of water on the scale first) from the middle. Read the tension and measure the cord's angle below horizontal with a protractor. Shorten and lengthen the cord and repeat: compare each reading with W / (2 sin θ). Use a scale rated above the largest reading the notebook predicts, and keep the cord well away from flat. Now hang the bucket below the middle on a second cord, at 30 cm, 60 cm and 100 cm. Give it the same small push each time and time ten swings with a stopwatch, and how long until the swing is a quarter of its start. That is French's claim, tested. Before hanging a real hammock, work out the pull on each anchor from its angle, and use anchors and straps rated well above it.

**George B. French** of Fremont, Nebraska, filed US 507,426 on 19 August 1891; it is dated 24 October 1893. His claims cover the slack rope, the sliding clasps with set screws, the suspended frame and the guy ropes. **Honest limits.** The patent gives no sizes or loads. The person's weight, span, rope lengths and loss per swing are examples; a real rope stretches, which the notebook leaves out.