Submerged Vessel, He Says, Can Go 65 Miles

Mr. Tesla Comments on the Idea of Resistance Under Water Advanced by Lord Kelvin.

FASTER THAN ON SURFACE

Inventor Says Aeronauts Overlook Important Law in Their Attempt to Attain High Speed.

TO THE EDITOR OF THE HERALD:—

In the European edition of the HERALD of October 1, Santos-Dumont has credited me with a theory which is not my own namely, that a higher speed can be attained in the water than by gliding on the surface. This idea was advanced long ago by Lord Kelvin and has been since accepted in all classical works as a manifest truth. A vessel completely submerged and creating no surface disturbance has nothing but skin friction to overcome.

In attempting to reach a speed of 100 kilometres, or 62 1/2 miles, the aeronaut evidently places faith in the demonstrations of Pictet with the hydroplane, paralleled by those of Langley with the aeroplane. But in both of these an important law has been ignored, of which, however, no hint or suggestion can be found in the entire scientific literature from Newton's principia to the most modern treatises and which profoundly affects the results in gliding and soaring.

The experiment which, as reported in the HERALD, Santos-Dumont is to make will forever dispel the popular notions of the hydroplane, according to which, were it not for air resistance, a speed of 360 miles would be attainable with his remarkable craft. In the light of the law I have discovered that this gliding boat, weighing, with operator and fuel included, five pounds per horse power, will reach only a speed of forty-eight miles. To attain 100 kilometres the motor would have to develop much more than 120 horse power. What is true of the hydroplane likewise applies, with a slight modification, to the aeroplane. But a submerged vessel of the Whitehead torpedo type could be propelled at a rate of sixty-five miles.

NIKOLA TESLA.
NEW YORK, Oct. 16, 1907.