Letter 122 Euler to Teplov
Berlin, April 14/25 1750
Synopsis: Euler reviews two papers , one on chronometers and the other concerning oars. Euler forces Gmelin's position. Euler/ Schumacher rift
[...] It is a great honor that His Excellency Monseigneur le President makes me by asking my advice on the two papers that you had the goodness to send me. I have read both with a great deal of pleasure, and to tell you how I feel is that I found the one concerning the self-winding clocks much better than the other, where the author proposes and new and more efficient way of stroking with oars. In regards to the former paper, I had the same idea quite a while ago to apply a pyrometer to a pendulum , so that with all the changes that temperature brings about, could be employed to wind the machine up, so that in some way the clock will appear to be self-winding, even though the power is explicit. It is for this reason that such a machine could not be called perpetual motion, since changes in the temperature are simply accidental and if it were to happen that the seasons are invariable for a long enough period of time, then the machine would be reduced to rest. The way in which the author employs to change the bars which are caused by the different degrees of temperature and are sensitive to change appears to be very ingenious, and I have admired the way in which he allows the wheels to always turn in the same direction and this without causing the clock to stop. However, I am under the impression that there is a simpler design for this mechanism, even though I do not see it clearly enough how it could be done. But as it is not more difficult to improve upon a discovery, this paper will always have an honorable mention in the Memories of the Imperial Academy.
However, as concerns the second paper, irrespective of the ingenious way in which the author presents the material, I am convinced that the proposition is far ahead of the author's intent, and it will never be more than pedestrian, due to the fact that the principle upon which the author has staked his discovery appears very mistaken. For even though a man can exercise considerably more force by using his weight, it cannot be a constant force downwards in such a way that the body is continually going downwards, he must rise alternately, and he must replace himself into his original position and by so doing the author promises that which is necessarily lost. So if there is any merit to this piece for practical purposes, I doubt that it will reside in the Memories. However, insofar that it contains a novel approach to oar construction, even though it would not be advantageous, it could serve to undertake valid research in other areas.
I have already had the honor to remark, Sire, that the Affair Gmelin will end to Your Excellency's entire satisfaction. It is without doubt the most important step and one to which I have primarily insisted on with my opening remarks to Mr. Gmelin. He openly admits to his error, and he implores Your Grace to discover within his heart the motive for the steps he took. I will insist even more thoroughly on this point in a letter that I will address to him today and I have no doubt whatsoever that he will wish to acquit himself with the greatest possible haste.
Recently, I had proposed to Mr. Schumacher a subject that appears very useful to astronomy with the name Mylius, and I have no doubt that Mr. Schumacher has not communicated the proofs upon which rest my recommendations. If You feel that it could be helpful to the Academy, You have but to tell me your wishes towards him.
Also, there are also some excellent telescopes for sale here, manufactured by the late Mr. Blumler, whose talents are well-known. His widow was in a destitute condition and had sent them here on consignment, and I had sent the specifications and the prices to Mr. Schumacher quite a while ago in case the Academy would need them.
I have the honor of being with the most perfect attachment to [...]
Translated from the French
by J.S.D.Glaus
