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240 Oct 3d 1846 Experiment on the cause of a ball being suspended on a jet [[three figures are sketched in the left margin, spaced down the length to display different experimental set ups]] Experimented this afternoon on the cause of the suspension of a ball on a small stream of water. The phenomenon is a very surprising one, and is not explained in the ordinary books. The arrangement to produce the effect was as follows. A bell glass was inverted, a glass tube passing through a cork inserted into the orifice. The tube being previously bent at the lower part, and drawn out so as to form a jet pipe, which gave a stream of about one tenth of an inch in diameter, and which spouts upwards about 2 feet and a half. The ball which answered best with the force and size of stream was one of maple wood of about one inch, or perhaps a little more in diameter. With a large ball, the effect was not as permanent, the ball falling off. With the smaller ball, the effect was produced for ten minutes at a time, the ball during the whole time continuing an oscillatory motion. That the effect is not due to an ascending current of air, as some have supposed, is shown by placing a piece of paper near the side of the jet, so as to intercept the current, the ball still remains suspended. [[image on left margin]] Neither is the effect due to a rolling of the ball on the side of the jet, as at [[underline]]a[[/underline]], for in these experiments the jet was so small that the powerful part of the liquid passed up on one side, when the jet struck the ball on one side, [[figure]] and consequently the rolling would tend to throw it farther off the jet. That a rolling tendancy does exist in the ball when the jet strikes one side, is shown by the following experiment. A glass cylinder was placed on two parallel wires, [[underline]] a b c d[[/underline]], a little inclined [[image in left margin]] so that the cylinder might roll down and touch at its side, the ascending stream in this case, the cylinder was made to roll back by the impulse of the water on its side, descending again by the force of gravity. [[end page]] [[start page]] Oct 3d 1846 Ball on jet 241 [[left margin]]four simple figures drawn down the length of the left margin[[/left margin]] it would again move back, and so on several times in succession, or as long as the stream was kept up. When however the cylinder was pushed a little into the stream, the water was observed to curve around it, and to be thrown off in a series of tangents (see figure), the cylinder did not then roll. The final conclusion from all the experiments, is that the effect is due to the tendancy of the water to move in a straight line. As it is caused to move in a curved line, the centrifugal force at [[underline]]a[[/underline]] draws the ball in the direction of the arrow, and constantly tends to bring the stream under the lower point of the ball. [[image]] When a string of fine silk thread was attached to the ball, and drawn, so that the ball not directly above the stream, the water was thrown directly over on to the hand which drew the string. [[image] A piece of cork in the form of a cube was not retained for an instant on the stream, in this case the force of the sides did not permit the centrifugal force to be developed. [[image] A ball with a larger pin through it was retained, the pin was observed oscillate through an arch of 30 or 35 degrees. Hence a rotative motion does not appear necessary to the ^[[success of]] the experiment. The ball however in some cases is observed to rotate.
