THE AVIATOR FLYING-MACHINE. 397 



are the organs that embarrass us, can we not find some sub- 

 stitute ? 



The electrical helicopters, with which we have obtained excel- 

 lent results, seem to offer a special adaptation of the screw to the 

 motor, which, like all electric motors, turns with an excessive 

 velocity — so that one of the organs seems made for the other. We 

 have often been struck, in our electric boats, with the fact that 

 the wake at the stern is hardly percei)tible. This is because the 

 helix of our steering motor-propeller, having the great velocity of 

 twenty-four hundred turns in a minute, enters the water as a 

 screw its tap. In our electric helicopter, likewise, the screw forms, 

 we might say, an integral part of the motor, thus supplying us 

 with a motor-propeller, India rubber offers a still more perfect 

 connection between the accumulator of potential and the motor — 

 the generator or accumulator and the motor being absolutely 

 identical. India rubber is a generator-motor. Hence, since we 

 can not eliminate the generator or the propeller from the appa- 

 ratus we imagine, we will absorb them and fuse them into the 

 motor. We will create a new organism sufficing for itself, and 

 will call it the generator-motor-propeller. We have ourself de- 

 vised a propeller of this kind, by the aid of the well-known Bour- 

 don tube, an instrument wliich is the essential part of the Bourdon 

 manometers. Electricity plays in it a part only secondary, but 

 necessary. This apparatus has so far given lis satisfaction, and 

 it may be that it will serve for some time as the essential basis of 

 machines heavier than the air. 



If the pressure of the gas contained in the tube increases, the 

 tube changes shape, and its elliptical branches tend to spread 

 apart ; while, if the pressure is diminished, inverse action takes 

 place, and the branches approach. If, then, we provoke a series 

 of alternate condensations and expansions, or increasing and di- 

 minishing pressures, in the interior of the tube, it will go through 

 a series of oscillations, of strong vibrations, capable of being 

 used as a motor force, chiefly and perhaps only in the conditions 

 under which we have placed ourselves. For the purpose of fur- 

 ther increasing the energy of the resistance of the tube, and also 

 of diminishing the volume of the chamber in which the explo- 

 sions are produced, we have inclosed in the interior a similar sec- 

 ond tube — an addition which augments the elastic force of the 

 engendered gases, while diminishing the expenditure of combusti- 

 bles. The whole of the system is represented by Fig, 1, and was 

 presented by us to the Academy of Sciences in December, 1870, 



The wings A and B are fixed directly, but with a rotary motion, 

 at the vibrating ends of the tube, suppressing all intermediary 

 organs of transmission by friction or rotation. Depression of the 

 wings corresponds to condensed pressures, and elevation tO dilated 



