Robur the Conqueror | Page 9

Jules Verne
Milnor, insisted that the
measurements should be remade by means of a rule graduated by the
micrometrical machine of M. Perreaux, which can divide a millimeter
into fifteen-hundredths of a millimeter with a diamond splinter, was
brought to bear on the lines; and on reading the divisions through a
microscope the following were the results: Uncle Prudent had
approached the center within less than six fifteenth-hundredths of a
millimeter. Phil Evans was within nine fifteen-hundredths.
And that is why Phil Evans was only secretary of the Weldon Institute,
whereas Uncle Prudent was president. A difference of three
fifteen-hundredths of a millimeter! And on account of it Phil Evans
vowed against Uncle Prudent one of those hatreds which are none the
less fierce for being latent.


Chapter III
A VISITOR IS ANNOUNCED

The many experiments made during this last quarter of the nineteenth
century have given considerable impetus to the question of guidable
balloons. The cars furnished with propellers attached in 1852 to the
aerostats of the elongated form introduced by Henry Giffard, the
machines of Dupuy de Lome in 1872, of the Tissandier brothers in
1883, and of Captain Krebs and Renard in 1884, yielded many
important results. But if these machines, moving in a medium heavier
than themselves, maneuvering under the propulsion of a screw,
working at an angle to the direction of the wind, and even against the
wind, to return to their point of departure, had been really "guidable,"
they had only succeeded under very favorable conditions. In large,
covered halls their success was perfect. In a calm atmosphere they did
very well. In a light wind of five or six yards a second they still moved.

But nothing practical had been obtained. Against a miller's wind-- nine
yards a second--the machines had remained almost stationary. Against
a fresh breeze--eleven yards a second--they would have advanced
backwards. In a storm--twenty-seven to thirty-three yards a
second--they would have been blown about like a feather. In a
hurricane--sixty yards a second--they would have run the risk of being
dashed to pieces. And in one of those cyclones which exceed a hundred
yards a second not a fragment of them would have been left. It
remained, then, even after the striking experiments of Captains Krebs
and Renard, that though guidable aerostats had gained a little speed,
they could not be kept going in a moderate breeze. Hence the
impossibility of making practical use of this mode of aerial locomotion.
With regards to the means employed to give the aerostat its motion a
great deal of progress had been made. For the steam engines of Henry
Giffard, and the muscular force of Dupuy de Lome, electric motors had
gradually been substituted. The batteries of bichromate of potassium of
the Tissandier brothers had given a speed of four yards a second. The
dynamo-electric machines of Captain Krebs and Renard had 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!
"And it is not dear," said Uncle Prudent, as he handed to the inventor in
return for his formal receipt the last installment of the hundred
thousand paper dollars he had paid for his invention.
Immediately the Weldon Institute set to work. When there comes along
a project of practical utility the money leaps nimbly enough from
American pockets. The funds flowed in even without its being
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