Pay! 
154 
Kiograms. 
Balloon, with thevalves\ 2). 040). eens, BluT0 
Cover, with rudder and suspension-ropes. . 70 
Hilexableiside:sihvaktsy.. Un en c's v1 Un eeh ee ea Oe 
Cary Pee) fea eed s bee ee ies Cac mee mt et LOO 
Motor, screw, and batteries, with liquid for 
Ps SOW 5 6 6 ay Nena GA Dae PANY 
Stopping-machinery (anchor and guide rope), 50 
Weight of material Bod ts -— 704 
Two passengers, with instruments . .. .. . 150 
IS ANASUM EC Ia roe st coed Icio ps Wen deed ce fen pat OOO 
Total weight . 1,240 
Allowing 10 kilograms, the lifting-force was 1,250 
kilograms. The capacity of the balloon being 1,060 
metres, the gas had a lifting-force of 1,180 grams per 
cubic metre, —a result not hitherto obtained in the 
production of large quantities of hydrogen. 
By the end of September the gas apparatus was 
ready for trial; the balloon was stretched out on the 
ground under a long tent, in order that it might be 
immediately inflated; the boat and the motor were 
stowed under a cart-house; and my brother and I 
were only awaiting good weather to make the trial. 
On the 6th of October there was a rise of barometer; 
on the 7th the weather was fine, with light wind; 
and we decided to make the experiment the follow- 
ing day, Oct. 8, 1883. 
The inflation of the balloon began at eight o’clock 
in the morning, and continued, without pause, till 
half-past two in the afternoon. ‘This operation was 
expedited by means of the equatorial ropes hanging 
at the right and left of the balloon, and to which 
were attached the ballast-bags. (The ropes are 
shown in fig. 2, which also presents the spindle- 
shaped balloon as seen from one end.) ‘The inflation 
completed, we proceeded to arrange the boat and the 
ebonite tanks, each of which contains thirty litres of 
the acid solution of bichromate of potassium. At 
twenty minutes past three, having heaped in the bal- 
last and obtained equilibrium, we were slowly raised 
into the air, a light east-south-east wind blowing. 
On the ground there was almost no wind; but, as fre- 
quently happens, it increased with the altitude; and 
we found, when the balloon had risen five hundred 
metres, that it attained a velocity of three metres 
a second. 
My brother was especially engaged in regulating 
the ballast, in order to keep a constant low altitude. 
The balloon was kept very regularly at a height of 
four or five hundred metres. It remained perfectly 
inflated; and the superfluous gas escaped by opening, 
under its pressure, the automatic valve, the action of 
which was very uniform. 
Several minutes after the departure, I tried the 
bichromate of potassium batteries, composed of 
four troughs with six compartments, making twenty- 
four elements in circuit. A mercury commutator 
enabled us to use at pleasure six, twelve, eighteen, 
or twenty-four elements, and thus to obtain four dif- 
ferent speeds of the screw, varying from sixty to a 
hundred and eighty revolutions per minute. With 
twelve elements, we found that the speed of the bal- 
loon was insufficient; but above the Bois de Boulogne, 
when our motor was working with great speed, with 
SCIENCE. 
or 
[Vor. III, No. | 
twenty-four elements a very different effect was pro- 
duced. The movement of the balloon became sud-— 
denly appreciable, and we felt a fresh breeze produced 
by our horizontal motion. With the balloon head to — 
the wind, pointing toward the belfry of the church © 
of the Auteuil, near our starting-point, we remained 
Fi4. 2. 
motionless, as we proved by noting conspicuous points 
beneath our car. Unfortunately it did not long 
maintain this position; but, after acting well for 
several instants, it suddenly began gyratory motions © 
which the rudder was powerless to completely control. 
In spite of the rotations which in later trials we were 
able to prevent, we tried the same experiment for 
more than twenty minutes, during which we could — 
perceive that we were over the Bois de Boulogne. — 
When we tried to change our position by cutting the — 
wind perpendicularly to its direction, the rudder — 
became inflated like a sail, and the rotations were — 
produced with much greater violence. From this we 
