developed a force of twelve horsepower and yielded a speed of six and
a half yards per second.

With regard to this motor, engineers and electricians had been
approaching more and more to that desideratum which is known as a
steam horse in a watch case. Gradually the results of the pile of
which Captains Krebs and Renard had kept the secret had been
surpassed, and aeronauts had become able to avail themselves of
motors whose lightness increased at the same time as their power.

In this there was much to encourage those who believed in the
utilization of guidable balloons. But yet how many good people there
are who refuse to admit the possibility of such a thing! If the
aerostat finds support in the air it belongs to the medium in which
it moves; under such conditions, how can its mass, which offers so
much resistance to the currents of the atmosphere, make its way
against the wind?

In this struggle of the inventors after a light and powerful motor,
the Americans had most nearly attained what they sought. A
dynamo-electric apparatus, in which a new pile was employed the
composition of which was still a mystery, had been bought from its
inventor, a Boston chemist up to then unknown. Calculations made with
the greatest care, diagrams drawn with the utmost exactitude, showed
that by means of this apparatus driving a screw of given dimensions a
displacement could be obtained of from twenty to twenty-two yards a
second.

Now this was magnificent!