The Translation According to Google:
You will find Ci after a text that I had put side for a certain time but which it was necessary to seize again in data-processing form to place it at the disposal. Here are which is made.
Herve Hénaff
Correspondence of Mr. Rousseau on the vélocipède unicycle
Marseilles, October 27, 1881
Reproduced with the pleasant authorization of the national Academy of arts and trades, numerical Academy http://cnum.cnam.fr titular of the royalties.
Mister the Writer,
In the n° 437 of Nature you give the description of the monocycle, and in the n°438, Mr. S.R. of Saint-Chamond, speaks to you about that which it saw in 1875 in Besancon, but here its history:
In 1868 everyone dealt with the vélocipède: my father, engineer manufacturer of road engines, was involved in the current; but its inventive spirit pushed it with the monocycle, and after a rather great number of tests, it was able to make me mount a machine exactly similar to that of which you give the drawing in your n°437.
We were very surprised little of time after having tried out the thing to see the same machine in Paris invented at the same time by Mr. Jackson, manufacturer of monocycles and tricycles.
The same idea had spouted out in several brains; but what astonishes me much, it is to see, thirteen years after, of the engineers believing to make a similar invention condemned for a long time, because here what I studied in the monocycle that I have gone up for thirteen years, but with which I never could travel. If I showed in Besancon, twice in Lyon in 1875, in Toulon, in Nimes, in Cannes, in Marseilles, etc, it is while returning to me in these various cities to take share with the velocipedic races, because I am large amateur of this sport, that I place, as make the English today, with the first rank.
The more the height of the double rim increases, the more resistance is large. At the beginning, my monocycle was with two circles like your drawing, the rays had 0m70, the total height of the instrument was of 2m80, it did not go although to the slopes. I then removed the double rim and his rays, then, louse to have all safety at the beginning, I added cranks actuated by the hands while I give the first impulse by beating the ground with the feet. Then, I have remakes the too heavy instrument, and I managed to have a monocycle possible of 30 kilog., but nevertheless impossible at the rise, and here why: It is which a slope of 0m has, 01 per meter and even with horizontal, the monocycle is always with the rise since one walks in a circle. While leaving, one skids hard, with a rise equal to the interior circumference of the circle; the dash given, resistance only decreases by half; it results from that that a monocycle of 3 or 4 meters diameter, built like mine
would be better; exceeded this size, we would have the resistance of the large wheel on the ground which would start to be felt. With the double rim, I examined a resistance three times harder at the beginning with the single one
rim of 0m, 10 thickness. My drawing gives you the exact demonstration that the practice provided me (fig.1).
Better a monocycle would be that which I managed to assemble and which I believed impossible. You will probably see it in Paris. It is an Italian acrobat who is here in this moment with the Crystal Palate and which makes run any Marseilles to see it going. I give you the drawing of it (fig.2).
Please accept, etc,
Rousseau
