1, making an angle of about 10 degrees. The low
specific gravity of the system enables ropes to be employed of as great a
length as 450 yards, each of them carrying 350 parachutes of 17.2 square
feet area. As half of these are in action at the same time, the total
working area for the two cables is 5,860 square feet. This immense area
furnishes a considerable amount of power even in a river of feeble
current. Comparing this with a floating water wheel of the type sometimes
employed, and supposing this to have only 172 square feet of working area,
such a wheel must have a length of 46 feet, a diameter of 23 feet, and
seventy-two floats, each 21/2 feet wide. The enormous dimensions thus
required for a comparatively small working area point sufficiently clearly
to the advantage which remains on the side of the parachute motor.
The general arrangement of the system is shown in the engraving. Behind
the return pulleys, D D, are attached cords, A A, with some parachutes
strung upon them. These present their openings to the current and preserve
the tension of the connecting ropes. At the further end of each cord is a
board, B, which is kept in a vertical plane, but lying at a slight angle
to the direction of the current; and this acts to keep the two moving
ropes apart from each other.
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