750 Transactions of the American Institute. 



all along ; it makes no difference. But you can only raise water six 

 feet by one pair. 



Dr. L. Bradley — Will you explain why one pair will not lift it 

 more than six feet ? 



Dr. P. II. Yan der Weyde — One turn of a screw propeller is as 

 good as. that of twenty. So, if you put twenty of these together, 

 the last one will lift it six feet, and that is all. Some months ago I 

 was invited to witness experiments at the Novelty "Works, and I 

 hold in my hand an invitation to make another investigation to-mor- 

 row. I found that a certain velocity of the propeller would not lift 

 the water more than three feet ; and that the velocity must be very 

 great to raise it six feet. The great objection to this instrument is 

 that it must be rotated at so great a velocity. And where there is a 

 column of water one hundred feet high, the friction of the pivot 

 below would be enormous. But here comes in the important 

 invention of the water-bearing. It does not stand upon a pivot, 

 but is suspended by a disc, under which water is forced with 

 sufficient pressure to support the weight, so that it is lifted from 

 its bearings and is suspended on the water, and revolves with little 

 friction. Observing that the water discharged from this bearing was 

 raised in temperature by the friction, I measured the amount of water, 

 and its elevation of temperature-, and found that the loss by friction, 

 in doing the work of a steam-engine of forty horse-power was only 

 two horse-power. Without the water-bearing, it would be impossible 

 to work this pump practically. 



The President — It was settled as early as Fitch's experiments, 

 about the year 1784, that one paddle was just as good as a dozen 

 together in the same right line. He found that the first paddle 

 moved the water, and was as effective as the series of paddles he at 

 first proposed. In the ordinary chain pump there is no friction, 

 except at the sides of the tube ; and, if worked at a sufficient velocity, 

 it produces excellent results. But in the common pump the water 

 has to turn in two different directions, and this consumes more power 

 than is required to lift the water. 



Mr. T. Shaw explained the water-bearing, and stated that in the 

 first experiment of the large pump at the Novelty Works, he had 

 holes bored twenty feet apart all the way up the tube. The pressure 

 was found to be nearly the same throughout the whole tube. The 

 current of water through the holes was very weak. 



Mr. T. D. Stetson — I should think that one propeller would do just 

 as well as forty. 



