'>f one hundred feet per second, in order 

 ti sustain a one hundred pound weight. 

 And in the second case, it has to luove 

 ji load of one hundred pounds, at the rate 

 vi onlj' fifiy feet per second, to accomplish 

 this. Mr. A, you are well aware of the 

 fact, that it requires double the power to 

 move a load at the rate of one hundred 

 feet per second, to that which is required 

 to move it at the rate of fifty feet per 

 second. You now observe the advantage 

 of the larger plaije. It only required 

 one-ljalf the power to sustain the one 

 liundred pound load, by using the larger 

 plane, to that which was required to sus- 

 tain thd sarrie load with rhe smaller plane. 

 St) then ii comes to this : We can lift the 

 one hundr d pound load with one-half 

 the ptiwer, if we quadruple the area of 

 the plane. Now if we choose we can 

 double this quadrupled area of the plane 

 and lift two hundred pnunds instead of 

 one, by using f!)^ full jiower of ilie motor. 

 Mr. A, you are probably aware of the 

 fact, that in the case of I he well known 

 water wheels, where the power i-* applied 

 by throwing jets of water against paddles 

 fixed upon their peripheries, that they 

 require gearing according to tbe velocity 

 of the jet by which thev are aci.ualed. A 

 large jet under low pn^ssure and velocity, 

 rotates the wheel with greac force, but 

 at a slow rate of nsotion ; and a small jet 

 under high pressure and velocity, rotates 

 its wheel at a high velocity, though it has 

 but little force, till we introduce gearing 

 to decrease the motion and increase the 

 purchase. Keep in memory the fact, 

 that in the case of hotli the large and 

 small jets, they are supposed to transmit 

 equal amounts of energv per second, from 

 their nozzles to their wheels. It is clear 

 Mr. A, that the constant strain between 

 the nozzle aisd paddles on the wheel, in 

 the case of the larger jet with low pres- 

 sure and velocity, is grca'er tnan that in 

 tbe other case, although they are trans- 

 niitting equal amounts of energy [)er sec- 

 ond, from their nozzle^ to their wheels. 



Mr. A, I read an account in a Scien- 

 tific paper, wtiich illustrate<l this law: 

 The statement was iiiftde that a spiders 

 weh forming a belt an-i placed on pul- 

 leys correspondingly dedicate, would by 

 lr;iveiiiig at the velocity of dght, trans- 

 mit about two hundreil and fifty horse 

 pojver. You are aware c>f the fact, Mr, 

 A, that in that case an enormous amount 

 of energy would be trdiismitted from 

 point to point persicutid, but the strain 

 upon the \ehicle which conveyed ihis 

 energy would he excedingiy small. Now 

 Mr. A, tile larger plane in ti.e case of 

 the iilustralive air-ship, and the larger 

 jet of water in the case of the water 

 wheels, represetit tbe larger jet of air in 

 the case of the air-ship. They illustrate 



the fact, that as we decrease their velocity, 

 we increase their pressure or reaction ; 

 And in the case of the spiders web travel- 

 ing at the velocity of light, the fact is 

 shown what a great amount of energy can 

 be transmitted from point to point per sec- 

 ond in the case of the air jets with but little 

 pressure or reaction as in that of the 

 spiders web. Now we may consider it 

 a natural law, that for transmitting a 

 given amount cf energy, in a given titue 

 from point to point, as we increase the 

 velocity of the vehicle conveying this 

 energy, the constant strain or pressure 

 on this vehicle is decreased, no matter 

 what form or nature this vehicle is. It 

 may he planes of air-ships moving di- 

 rectly or indirectly against tbe air. It 

 may be a belt fixed on pulli^ys, a revolving 

 shaft or a reciprocating pinion rod, a jet 

 of water or a jet of air. Th se are all 

 simply cases of transmission of energy 

 from point to point, To makn this c^se 

 more clear, in regard to transmitting 

 ener.i^y from poitit to point, we will for 

 illustration suppose a belt to carry one 

 hundred p mmls at the rate of ttn feet 

 per secoiid. It will then transmit from 

 point to point oim thousand foot pounds 

 of energy per sec' nd. We now suppose 

 the belt carries a load of fifty pounds; 

 you understand then it will have to carry 

 this load at the rate of twenty feet per 

 second, in order to transmit the one 

 thousand foot pounds per second. You 

 observ ■ in this case, that we doubled the 

 velocity of the vehicle and transmitted 

 tbe one thousand footpounds per second, 

 though the strain upon the vehicle was 

 oidy one-half that in former case. This 

 then makes it clear, that as we increase 

 the s[)eed-of the vehicle carrying a given 

 amount of energy per second, we lessen 

 the strain upon it, and yet convey tbe 

 .'same amount per secand as before. Now 

 in the case of the air jets, they are similar 

 to bent springs placed betw en bearings. 

 The springs being in a state of ten-ion 

 and {iressing equally against each of their 

 bearings. The mouths of the nozzles 

 form on" of their bearings and the outer 

 atmosphere the other. And the weakest 

 points in the air-jet spring.s (shall I call 

 them) are immediately at the mouths of 

 tbe nozzles, where the velocitj' of the 

 jets are greatest. 



A — But Mr. B, I suppose we shall have 

 to give up tlie idea that a small propeller 

 moving at a high velocity, will bring about 

 as great a reaction as a large one moving 

 at a slow velocity, with an equal power 

 in each case to actuate them. 



B — Yes Mr. A, that idea will have to 

 be given up in all forms of propellers. A 

 plane tnoving broad-sided directly or 

 indirectly against the air, is practically 

 the same; and this law we have been 



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