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Introduction
To Euler's Correspondence with
Frederick II
September 4, 1741- February 1, 1777
by Eduard Winter
Frederick II played, without any doubt, an important
role in Euler's life during the period of 1741-1765.
Under the tutelage of this king at the Berlin Academy
of Sciences, Euler sustained a theoretical and applied
oeuvre which has been entered forever into the annals
of the history of science. There is, as well the Frederick
II and Euler correspondence reflecting the celebrated
genius' activity during his Berlin period demanding
a special section in this edition of Euler's letters.
The total is 87 letters, 28 of which are Euler's.
This correspondence constitutes a wealth of information,
but what is surprising, is that it does not measure
up to the personal relations between Euler and Frederick
II. This is explained by the paucity of direct contact
with Euler. Their relationship passed through his
administration or through those persons of confidence
employed by him, who had relations with the Academy
of Science- Euler's workplace- as equally for Maupertuis,
d'Alembert, d'Argens, de Catt to only mention a few.
There could be no question concerning the editing
of material which was saved between Euler and Frederick
II without an overview of the entirety.
There are some preliminary introductions which
are indispensable. It is passionately entertaining
for the historian to place these two strong personalities
face to face, one making a mark in the history of
sciences and the other in the political arena. These
men are fundamentally different one from the other,
not only separated by their primary activity but also
by their characters. On the one hand a mathematical
genius who catapulted his subject very far very quickly.
Born in the home of a pastoral preacher and having
started his studies in theology, both modest in his
exterior appearance and his being. On the other hand,
the shining example of a king garlanded by military
conquests, who enjoyed nothing better than spirited
and dashing conversations. Without a doubt, two of
the most opposed characters that it was possible to
know.
We know how Frederick II passed judgment onto
Euler, by a letter that was written to his brother
Wilhelm August on October 31, 1746 "I already
explained to you that your conversation with Mr. Euler
would not be edifying.[...] Amongst the people who
know, there are exceptional number-crunchers, commentators,
translators, compilators, each having a role to play
in the Republic of Science, who are everything except
smart. They are employed similarly as Doric columns
in architecture. They belong to the under-structure,
they support the entire structure, unlike the Corinthian
columns which are merely ornaments." And again,
on July 6, 1737, Frederick offered Voltaire a maliciously
ascerbic saying; that "the king needed to maintain
an Academy of Sciences as a country squire needed
a pack of dogs". The need for foreign representation
and conscious of its importance balanced the scales
in Euler's favor in Frederick's soul.
Euler as we know felt honored by Frederick II's
invitation in 1740 as well as the fact that it
extricated him from a difficult situation in Petersburg.
During his entire stay in Berlin, Euler remained very
close to the St. Petersburg Academy, which is confirmed
by his regular correspondence and his scientific collaboration
with this institution. He always accomplished his
undertakings even after he left for Berlin with the
title of foreign member and the St. Petersburg Academy
provided him with an annual stipend.
In Berlin, he was committed to his task and
to the service of the king in the establishment of
the academy where with his dominating presence he
was able to dispense his scientific knowledge to answer
important technical questions. His loyalty was particularly
manifest in the 1750's. However, after the Seven Years'
War in 1763, when Frederick wished to conduct the
business of the academy himself in the spirit of a
"French academy" , Euler's devotion came
to an end. It was then that he did everything to leave
Berlin as quickly as possible.
In reality, if Euler could have resisted all
of the king's attempts to bring to fruition the radical
tendencies of the Enlightenment at the Academy in
1748 while Maupertuis, with the inclusion of La Mettrie,
a French encyclopedist, it was no longer possible
in 1763 as d'Alembert became one of the king's counsellors.
In a general way there was a diametrical positioning
of these two men due to a profound difference in doctrine.
In opposition to his father who was spiritual, religious
and pious, Frederick II had come under the influence
of liberal thinkers in his early years; Euler ironically
designated them as "miserable men". In 1763
Euler became an active member and a leader of the
Consistory of Berlin's Reformed Church.
Euler critically opposed even moderate proponents
of the Enlightenment like Leibnitz and Christian Wolff
they represented by their philosophical conceptions,
a determinism and optimism too contradictory with
the traditional doctrines of free will and original
sin. For Euler, they were concepts, which lead to
atheism if one denied the action of the spirit on
the soul. On this last point Euler thought it possible
to voice a protest as a physics professor, when we
read the nineteenth, "Letter to a German
Princess". However, Frederick II who was pleased
to be called the " Philosopher of Sans-Souci"
went even further than Leibnitz and Wolff, claiming
a god entirely different from Euler's.
One can easily understand that based on these
differences, not to mention the diversity of comportment,
tastes, etc., the two men did not find common ground.
No real intellectual, evenhuman contact, was possible
between them. Their correspondence reflects this clearly.
However, Euler's will to contribute to the scientific
and economic well being of Prussia, manifested itself
as an area of fertile growth.
1.
Frederick's campaign to bring Euler
to Berlin;
Euler's genesis in the Prussian capital.
Having recently come to power, Frederick II thought
of rededicating the Academy of Sciences. In the June
27, 1740 letter he exposed Voltaire to his plans on
this subject. At the time he considered a shared presidency
with Christian Wolff and P.L.M. de Maupertuis. He
indicated in the same letter the names of Algarotti,
s'Gravesande, Vaucanson and ending the list, Euler.
Christian Wolff rejected the idea of going to Berlin
based on the fact that with Maupertuis there would
be little to administrate. As Praeceptor Germaniae,
he preferred to teach as a professor more than to
serve as an ornament to the throne and raise "
cadets". He explained how he felt to Reinbeck
on his arrival in Halle on December 10, 1740.
Frederick II spent considerable effort to
acquire Euler. He speaks of a deposition that was
written in the king's a journal with the day to day
deployment of the situation and his own efforts to
follow through on the king's call to Berlin. It took
all of Euler's tenacity to succeed in receiving a
sabbatical from the St. Petersburg Academy. That was
done by overcoming Schumacher's opposition, the very
powerful head of the academic chancellery of Petersburg.
The historian who recognizes Schumacher's influence
and his methods can understand what is written between
the lines in the simple acts of the days' proceedings.
Without the help of the exceedingly forceful Prussian
envoy, A. von Mardefeld, Euler would have had great
difficulty in gaining Berlin. However, behind the
envoy there was Frederick II, whose very circumspect
orders reined in any solitary action on the part of
the envoy. Nothing is more revealing of Frederick's
thought than the importance that he attached to having
Euler at the Academy of Sciences in Berlin. We can
understand why Euler found it propitious to bring
his daily journal to the king's attention. The fortuitous
outcome of the situation demanded exceedingly protracted
and patient steps on the part of one and the other.
Meanwhile, Frederick II had arrived in Silesia
and was conducting a very committed armed battle
against the Austrians. It was at Reichenbach's camp
that Frederick welcomed Euler in Berlin on July 25,
1741. But Euler wanted above all to receive his appointment
and at this point Jariges interceded with the king.
To make some money Euler gave mathematics lessons
at the home of the Duke of Wurtemburg with Frederick's
blessing from his camp at Zynam on March 1, 1742.
War time is a difficult time. Euler landed
between Scylla and Charybdis. He had left Petersburg
principally due to the political instability and he
arrived in a Prussia plunged by its king into trying
belligerent times. Also, it is not before September
6, 1742 when during a mathematics class that Euler
is hailed by these words, "How society in general
and the present members particularly, are pleased
to welcome and recognize Messrs Euler and Lieberkuhn
as members of the mathematics department. We promise
on their behalf to offer counsel, assistance and friendship
for the honor and betterment of society, which is
noted by the assurance that there is work of the most
valued nature to be done." One can see the seriousness
with which Euler envisioned his task as he writes
to Jariges, the permanent secretary of the academy
from 1733-1748 on September 7, 1742. In this text,
Euler provides detailed instructions on the way in
which, "to come to the aid of astronomy which
has fallen into such disuse." At the meeting
of September 6, 1742, the issue surrounded the 7th
volume of the Miscellanea Berolinensia, to which Euler
himself contributed five papers and made the printing
of the edition possible. That was the final breath
for the old Academy.
However, the beginning of the new one had
to wait. The first Silesian war having ended, the
second appeared on the horizon. Euler's increasing
impatience shows itself in his letters of January
19, 1743 and again on October 19, 1743.
On August 1, 1743, under the direction of the
king's favorite, Fieldmarshal, Count Samuel de
Schmettau, a literary society was started at which
Euler provided numerous scientific reports. He seized
upon any occasion to display a dignified topic under
the guise of a Academy. However, that was not the
purpose of the literary society and Euler did not
want to exhaust his efforts on behalf of his Swiss
compatriots, Hedlinger for example. Teaching mathematics
to the princes did not satisfy him, however, he found
the time to tell the king with evident satisfaction
of his success in Magnetics, the work which he wished
to send for the 1744 Paris Academy prize.
Despite Euler's zealous collaboration, the
Literary Society did not constitute as its name implies
the birth of a new Academy of Sciences. While discussing
his activity in a letter to Goldbach on July 4, 1744,
he explained, "leaving no doubt of the self-imposed
restrictions, and for these reasons, I avoided pure
speculation and mathematical calculations, for the
better part I discussed Physics."
At the end of 1743, he joyfully accepted the king's
decree through the intermediary of minister Otto
von Viereck to re-transform the Literary Society.
This plan which until now was unknown, is of fundamental
importance in understanding the edification and development
of the future Berlin Academy. One is astonished by
the brevity and the simplicity of the plan elaborated
by Euler. This plan represents the organization of
Science to an exceptionally high degree. The goals
of an academy of science, had as its vocation the
necessity to produce the best, and that must be attained
by a simple but efficient process.
Among the sixteen propositions announced by Euler,
fourteen are dedicated to this process. They illustrate
the way in which science must be encouraged in the
most productive way by the Academy. Recourse to the
members of honor, "these distinguished gentlemen",
should encourage this interest, but everything should
be done to avoid the Academy becoming a place of institutionalized
honor and ceremony. " The most important point
rests in the designation of the ordinary members of
each category." Euler says in the twelfth proposition
that the significance of the Academy will depend uniquely
on the scientific value of each ordinary member, who
must be selected with the greatest circumspection.
Euler equally deals with the financial assistance
of the Academy in the eleventh proposition. This corresponds
precisely with his practical sense of bringing a special
focus to the development of the economic base which
he considers to be a necessary condition to pay for
research. One can still read in the last recommendation,
where he considers the financing of scientific works.
The overall picture is a real plan for an organization
which today, still merits our attention.
The statutes of the new Academy of Sciences established
by the king on January 24, 1744 on the occasion of
his birthday do not distance themselves from Euler's
project except on one essential point. Euler foresaw
a class of Medicine, classified into the Natural Sciences,
and Physics which does not appear, due to its fundamental
nature because it belongs classified in the Philosophy
category. His confrontation with Wolff's metaphysics
was applied on this basis which was not satisfied
in the 1744 statutes and would only come about with
a ruling in 1746: the amendment of president Maupertuis
would allow him to exercise considerable influence
in the philosophical direction of the academy until
1763.
In 1744, after the royal ratification
of the statutes, accepted at the first meeting
of the new Academy took place at the Berlin Palace
on January 23. The progress of scientific life took
place only very slowly, due to the fact that Mars
pushed all aside again in 1744-1745 with the second
Silesian War. The immense zeal that Euler manifested
for science reveals itself in a remark during the
academic session of January 29, 1744 concerning a
new observatory for the Academy. However, the king
was less interested in the sciences than in a good
treatise on artillery and that is why Euler writes
to him at the end of 1744 concerning the work of Benjamin
Robins, New principles of gunnery, which he translated
into German and published with his own important commentaries
in 1745 with the title Neue Grundsaetze der Artillerie.
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2.
The reconstruction of the Academy
by Euler
under Frederick's aegis
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It is only after the second Silesian
War at the end of 1745, that Frederick II could
begin thinking of the Academy's organization. On February
1, 1746, having been designated as president and presented
as such, Euler immediately began to teach the mathematics
class. The ideal situation that Euler had determined
- to contribute an essential part of the realization
of an academy - began to be realized albeit still
incompletely. The intellectual compatibility between
Maupertuis and Euler was excellent , they had both
been students of Jean I Bernoulli in Basel. In general,
their scientific and philosophical thinking went hand
in hand.
To appreciate Euler's insightful
ideas coupled with Maupertuis' assistance, it
is sufficient to see the Academic Regulations promulgated
by the king on May 10, 1746, which defines the categories.
Physics must be categorized into the experimental
philosophy or speculative philosophy dependent on
whether it is conceived of as either practical or
theoretical. In any way it belonged to philosophy.
Euler's ideas triumphed on the occasion of the question
posed by the Academy in 1747 for the 1748 prize, concerning
the Leibnitz/Wolffian monadic theory. With Euler's
recommendation, the prize was attributed to the lawyer
Justi of Sangerhausen, who was opposed in his speech
to Leibnitz and Wolff controversy, albeit in a different
fashion.
While Maupertuis represented the
academy to the outside world, it was certainly
Euler who set the tone. The former had all the king's
confidence despite the royal misanthropy and defiance.
The academy was Euler's principal place of activity,
but plays only an insignificant role in the correspondence
with Frederick II during this peaceful decade of reconstruction.
However, protected by Maupertuis, Euler obtained in
his own right the king's confidence who willingly
allowed for his counsel in which his expertise is
found in many areas of his correspondence.
Euler knew how to garnish royal favor
on his behalf when he asked to have his nephews inducted
into the Prussian army. Later there were technical
difficulties that the Prussian administration could
not resolve and Frederick II submitted these to Euler.
Thus the king asked Euler on April 30, 1749 for the
solution to the navigation problems on the Finow canal
which joins the Oder and the Havel rivers. After a
detailed visit which was conducted by lieutenant-colonel
von Balby of the Army Corps of Engineers and Baumann
the Potsdamer aristocrat, Euler communicated the results
on May 14, 1749. In the report, the results are primarily
focused on the regulation of the pressure in the numerous
locks. As it consists of a report formulated as a
communal effort and Euler the sole author, it is designated
as 15a. The Finow canal was particularly important
to Frederick II. Thanks to him a river system traversed
Prussia's interior and by connecting Magdeburg to
Stettin created this city as the only maritime port
of Prussia besides Hamburg.
Shortly thereafter, on September
15, 1749, Frederick II submitted a project to
Euler of an Italian lottery and his advice was forthcoming
on September 17, 1749. On September 27 1749, the king
thanked Euler for his calculations and wished for
an expert opinion for a machine destined for Sans-Souci.
It appears on the report from Euler to Frederick II
of October 17, 1749, that it was in regards to water
pumps operated by windmills. Euler racked himself
for the calculations and arrive at the most efficient
performance for such pumps. He arrived at his answers
after initial difficulties. The calculations proved
correct, for which Frederick II thanked him on October
21, 1749.
Within the same time frame and thought process, Euler
wrote " Demonstration for a horse-powered water
machine which can raise 36 tons of water in 12 seconds
to a height of 5 feet". Letters 17, 19 and 19a
constitute interesting contributions to the history
of science and its technology, with relations between
science and technology that are still valuable today.
Probability calculations have practical applications
in its capabilities relative to a lottery, and mechanics
is placed in relation to the movement of fluids. Euler
always saw science as a productive force and the crossover
between theory and application was always done in
a sure and definite way. It is in this same vein that
he always worked towards organizing and administrating
the academy.
Euler was well-known for the numerous
and often noteworthy interventions on behalf of
bright candidates due for consideration even outside
of any positions relevant to the scientific field.
As was in the case of J.M. Van Loen. He was issued
from a respectable Dutch family and was a parent of
Euler's wife. After a few itinerant years, he established
himself in Frankfurt-am-Main where he married Goethe's
eventual great-aunt. In 1746 Frederick II offered
him the presidency of the Consistory of the Reformed
Church of Berlin. He declined the offer and addressed
himself to Euler whom he asked for his help to intervene
with the king in an attempt to get another position.
Euler requested without success, at least that is
what we are able to glean from a letter from the king.
What transpires is that Van Loen obtains the position
of President of the Prussian government of Lingen
and Tecklemburg counties. He hesitates and implores
Euler's help to supplicate the king. Euler felt responsible
for having brought Van Loen to Prussia. This case
is characteristic of the tenacity with which Euler
stood up and fought for his friends.
Euler attempted to win the king's
good graces with the execution of a medallion
created by his compatriot Hedlinger. He recognized
Frederick's ambition and his love of the arts. Euler
even went further in his attempts of captatio benevolentiae
as we can note by a package of fruits sent to the
king from the garden at Ma, which Euler had acquired
at Schoneberg near Berlin. The king appreciated the
attention of the fruit basket as was showed by the
note of thanks of May 26, 1753. A little while after,
the king promised to assume his nephew Vermuelen's
side in an inheritance dispute.
Concerning the personnel resources
of the Academy, Frederick addressed himself directly
to Euler. Such that on July 19, 1753 the king requested
confidential knowledge of what Euler thought of J.H.
Pott's request to have a certain Kurella as his collaborator
with the title of second professor of chemistry. The
king provided Euler with the necessary arrangement
to examine the situation and to bring about a loyal
supporter. This report was never found and was probably
of a negative vein, as the king's letter to Euler
of July 23, 1753 indicates. Pott wanted to have a
family member by the name of Kurella, a disciple who
according to Euler was visibly unqualified. The overwhelming
confidence of the king allowed Euler to have a copy
of the refusal.
In view of his relationship with
Frederick II, there is nothing surprising that
Euler was able to obtain a rare dispensation from
military lodging and maintenance. On August 15, 1753,
Frederick wanted a report from Euler on the nomination
of a second professor of anatomy to the Academy, this
report being favorable, the king confirmed the nomination
on August 18. After the nomination of the second anatomy
professor, W.C. Brogger, another followed concerning
botany. There also Euler's recommendation was adopted
by the king.
Euler hastened to provide for the
nomination for the second professor of chemistry
and suggested K.Ph. Brandes, after having eliminated
Kurella which Pott wished for. The proposal written
by Euler is missing, but Brandes' nomination to the
rank of chemistry professor was accomplished by Frederick
II on October 23, 1753. However Pott a member of the
Academy since 1722 made great objection to having
Brandes by his side. Euler had to accomplish this
project by finalizing the fine print by the end of
1753. However, Brandes realizing that there would
be nothing but endless complication with Pott, accepted
an invitation to Marburg; an invitation that Euler
already made mention of in his letter. Euler's manifest
tenacity is still apparent in this case. Soon after
Brandes' departure, he had him elected as a foreign
member in 1755 and in 1760 on Potts' retirement, Brandes
was recalled to Berlin with the title of ordinary
member.
It is on April 14, 1754 that Christian
Wolff, Euler's ideological foe, died in Halle.
Euler must have considered it to be a supreme philosophical
triumph that he was allowed to designate Wolff's successor
at the University of Halle. In effect, Euler received
his mission paper from the king on August 8, 1754.
He fully wished to enjoy his triumph in proposing
Wolff's most exacting adversary, J.A. Segner of Gottingen.
However, he had the foresight to make preliminary
contact with Daniel Bernoulli and asked him for a
power of attorney. He knew very well that Daniel Bernoulli
who was elected as a foreign member in June 1746,
would not wish to leave Basel where he had become
the head of the Mathematics department.
The fact that Bernoulli rejected
the position was communicated to the king on September
8, 1754 which left the avenue open for Segner's invitation.
In this same letter, Euler presents him as the very
summit of academic achievement, however difficult
to recruit. Euler was well-versed in his king's thirst
for glory, but also his greed. He knew that he had
to obtain the best possible conditions to successfully
complete Segner's transfer to Halle. The after-the-fact
letters reveal all this. In the November 4, 1754 letter,
the king reveals his satisfaction for Segner's appointment,
even though he complains of how deeply he must enter
into the state's coffers. The story of Segner's recruitment
is a great masterpiece of psychological maneuverings;
but it is also a pointed fact which concerns Euler
because wolffianism, so despised by him, appeared
to be all but out of fashion in Prussia, at least
that is what he was lead to believe for the moment.
In effect it was necessary to fund
equipment that was needed for the chairs of Mathematics
and Physics in Halle and the negotiations stumbled
on until the beginning of March 1755. Interesting
deliberations for the history of science because they
offer detailed insights on the instruments necessary
to the chairs. However, it is only with Frederick
II's March 6 1755 letter to Euler that the Segner
appointment is effectively resolved, in such a way
that Segner was able to begin his classes for the
1775 summer semester.
With Segner's appointment, victorious
piety descended heavy-handed from Halle to Salle
onto that " dangerous liberal thinker" Wolff.
A first effort had already been attempted by Joachim
Lange. He, father of Johann Joachim Lange who rooted
himself to Wolff and abetted Wolff's estrangement
from Halle, with the intentions of providing a clear
path for his son to the Mathematics and Physics chair.
Wolff's successor was not the insignificant J.J. Lange,
but the vigorous Segner who allowed wolffianism to
be battled with greater advantage on the science front
instead of the pious philosophical front.
Euler's recommendations concerning
the distribution of mathematics classes between
Lange and Segner received the king's approval on November
23, 1754. The transmission of the royal orders to
the two professors made by Euler is missing, but Segner's
and Lange's acceptances have been preserved. But this
did not only affect wolffianism which was suspected
of atheism; Segner had placed into doubt the mathematical
and scientific foundation of wolffianism. This controversy
was extremely important for the future of German thought,
and Euler contributed with his efforts directed to
Frederick in favor of Segner.
During the same period, Euler was
solicited either directly or indirectly by the
king for expert opinions. On November 6, 1754 by orders
of Frederick II's cabinet established on October 29,
1754, Euler furnished a report on the establishment
of a construction plan for mills originated by the
architect Bluchten. It was an unfavorable report indicating
that the proposed invention was not in accordance
to the principles of mechanics. On May 23, 1755 the
king addressed a private order to Euler requesting
how to evaluate and improve the salt content "in
my salt ponds at Schoenbeck". Euler conducted
the report, as it appears as a response on May 25,
1755, unfortunately, the report itself has not been
preserved. The king thanked Euler for his calculations
in his May 27, 1755 letter.
However, in his letters there is
also question of the nomination of A. von Haller
to the position of curator at the University of Halle.
The Swiss Haller , well-known for his position establishing
the Academy and the University, was an excellent naturalist
and doctor of medicine as well as an former student
of de Boerhaave. For this reason he was in contact
with all of the scientists in Europe interested in
medicine and the natural sciences. de Boerhaave's
scope of influence reached far and wide; he was represented
in Petersburg by L. Blumentrost, in Vienna by the
Dutchman Van Swieten and in Paris by the Portuguese
Sanches. All three had been students of de Boerhaave.
Since September 4, 1759, Haller was a foreign member
of the Berlin Academy. To install him as an ordinary
member would be a significant coup for Prussia. Euler
knew the king's mind, Frederick acquiesced on his
recommendation immediately.
Taken from a letter to J.G. Sulzer
dated April 25, 1755, Haller expressed his desire
to work for Frederick. He especially relished the
thought of obtaining the position of curator for the
Academy, along with the condition that funding was
available. He indicated that he had already received
an invitation from the king to come to Berlin in 1749.
An invitation without follow-up because Maupertuis
feared that Haller's glory might be eclipsed by the
presence of a truly famous genius. On May 27, 1755,
Euler wrote again to Haller in Bern and presented
him with the offer to come to Halle to fill the position
of chancellor of the university, which he wrote to
the king on May 28. He mentioned a salary of 2000
R. Thalers. It was necessary to do something so that
" the University of Halle could assume the advantage
over all the others of Germany" ; Euler stroked
this hope with Segner, but not necessarily with Haller.
He was not so smitten with Haller to end up in Halle
at any price. However, he wanted to show the dedication
of his efforts in impressing the king.
The latter was interested to know
what Haller's conditions were. However, in the
meantime, Euler had provoked the king into indecision
concerning Haller. Frederick ended up by thinking,
as he wrote to Euler on June 9, 1755, in a letter
that has not been preserved, that Haller only wished
to get out of the Hanoverian government some supplementary
benefits to the University of Gottingen, and had not
seriously considered going to Halle. Euler reinforced
Frederick's defiance in regards to Haller, which comes
out clearly in his July 7 letter to the king to which
he adds Haller's letter. Due to the interest that
Haller's letters to Euler add to the history of science,
detailed extracts are compiled with the footnotes
of Euler's letters to the king.
On August 13 1755 Haller bears his
expectations. They exceed the 2000 R. Thalers
that Euler had originally presumed. Besides, Haller
did not wish to sign on for 10 years. Euler informs
the king in his letter of August 28 1755 and the king
returns the acknowledgement on the 30th. He finds
that the 3000 R. Thaler and the ancillary benefits
"excessive", and allows Euler to organize
the remaining negotiations. We are aware of Haller's
response of October 28, 1755 to Euler's letter of
September 2, 1755. He tells of 2400 R.Thalers and
places a great emphasis on his desire for leisure
and freedom.
On December 27, 1755 Haller told
Euler that he had communicated his final refusal
to come to Prussia directly to the king . He wished
to spend the rest of his life in Bern, his country
and he preferred "liberty, life's little pleasures
and health" to the sparkle of a scientific organization
and the indifferent salary. Even though Pfaff filled
the University curator's position in Gottingen, Euler
was able to prove his zeal by doing everything possible
for the honor of Prussia and the king. Soon after
the king received the title of foreign member of the
Paris Academy. It was an important distinction, because
there were only ten positions of this category. The
king received this news with great joy. Frederick's
relations with Euler had attained their apogee. The
years 1746-1756 were Euler's Golden Age.
3.
Euler and Frederick II during the
Seven Years' War
In August 1756 the Seven Years' War broke out.
Soon Frederick found himself facing the largest military
alliance imaginable on the European continent. Those
of the three great powers; Russia, Austria and France.
Interesting fact: Euler a pensive and advised individual,
had thrust himself to points of enthusiasm for the
Prussian king who was armed against a world of enemies.
As such he employed himself even to translate letters
from the Russian officers that they we able to intercept.
1758 was a banner year for such activities. With a
certain degree of discretion and prudence, Euler tried
to hide his love for Russia, even into October 1756
he organized the election of professor F.U. Apinus
of Rostock to the rank of ordinary member at the St.
Petersburg Academy as a physician. He left for Russia
while the war was in full swing and no less delivered
his inaugural speech at the Russian academy on May
23 1757.
Maupertuis presided over the Berlin Academy for
the last time on June 3, 1756; his illness caused
him to leave and never to return. Euler remained in
Berlin enjoying a certain peacefulness despite the
comings and goings. For all intents and purposes he
was the acting President during Maupertuis' absence
and replaced him after his death in Basel in 1759.
Maupertuis' nerves had become very fragile and his
state could not support the royal decisions of back
and forth and back and forth. Euler wrote to him on
February 17, 1759 to beat back his depression,
"That God protects our King ! That Frederick
lives, reigns and triumphs, this is our wish along
with M. Formey."
Euler took such opportunistic steps that he even
offered his son Karl to the Prussian war machine.
As he expected, the king saw this as a act of patriotism
and sincerely and profusely thanked him for, "his
show of loyalty and his his attachment to his homeland."
On September 14, 1759 Euler sent Frederick II a pair
of note-glasses as well as a telescope on behalf of
the now defunct President of the Academy. In his letter
of September 14, 1759 which accompanied the optical
instruments, Euler informed the king of his own fruitful
activities regarding the perfecting of the instruments.
He concluded the letters with the hope that his son
Karl will show himself worthy of the honor that the
king has bestowed on him by inducting him into the
Prussian army. In his September 15, 1759 response,
Frederick encourages Euler to continue his improvements
to the telescopes. But he has little time to discuss
the matter: the war is thoroughly absorbing.
The war was expensive and the heavy losses
and numerous reversals became very clear in Euler's
eyes, at least after 1760. In comparison, Russia's
grandeur is much clearer. Berlin's occupation by the
Russian troops in the fall of 1760 brings him closer
to Russia and the material losses which he sustained
are in large part indemnified. His relation with Russia
, which had never been completely interrupted were
rapidly re-established. One can see this by the growth
of the correspondence that Euler exchanges with G.F.
Muller in Petersburg. Of the two letters written during
the period 1758-1759, one passes to seven in 1760,
to eight in 1761 and eleven in 1762 and thirteen in
1763.
At the same time, as soon as the war is over it
is clear that Euler attempts to attract Frederick's
attention by all possible means. On behalf of the
Directory of the Academy, Euler as a representative
was preoccupied in June and July 1763 by finding a
solution satisfying the demands of science as well
as the refunding the finances which were ruined by
the war so as to place the botanical gardens of the
Academy back in shape. He also counseled the king
on his request of August 17, 1763 concerning a lottery
which were to refund the depleted revenues. On this
occasion the king displayed his recognition. To better
merit this recognition, Euler brought up to Frederick
II the project established by a Coulais named Denffer
concerning the manufacturing of porcelain. This project
which is dated from August 14, 1763. The king thanked
him for is assiduity on August 30. If Euler hoped
for this royal approbation, it was because he desired
to finally achieve supremacy at the Academy which
he had been directing since 1746, due to his influence
on Maupertuis.
4.
Uneasy departure for Euler from Berlin
As for Frederick II, he did not even consider
placing Euler at the head of the Academy. With
the war over, the king became even more avid for glory,
increasingly stingy and much more suspicious. These
excesses of character prohibited him from granting
Euler any real confidence. For him, Euler would certainly
remain a great scientist, a "geometer" who
would be able to research all the knowledge to the
fullest of their applications, but he did not cut
a handsome figure. Frederick II could not entertain
a "spiritual" conversation with this "
limited cyclops", which was a requisite condition
for a man to become the president of the Academy.
It is with this in mind that Frederick II, thought
more of placing d'Alembert in the position who he
thought of when Maupertuis first became seriously
ill.
To this one must add the fact that Euler became
the declared supporter of David Kohler the responsible
party of the Academy's finances, the probity of which
Frederick II had doubts back to 1746. This sort of
support did not please the king. After the war, the
State coffers were empty, the country's resources
at a low ebb and the king tried everything to fill
them. He took a great interest in looking in to the
sale of calendars which he had awarded as a privilege
to the Academy. Based on this did the State's cashier
Kohler find occasion to fill his pockets? Kohler,
under the presumption of a wise decision and facing
a monetary devaluation, and following the example
of his king, removed the good coinage from the academic
accounts and replaced it with paper money which lost
two-thirds of its value in the following years. The
king's defiance became evident in 1763 and his discontent
with Euler grew. Euler's philosophical adversaries
at the Academy like J. G. Sulzer, heated the irons
by offering anonymous warnings to the king and by
that brought about Euler's own discontent. Certainly,
in 1746, Euler made himself very useful to the king
by and through reports on the telemetry of Ximenes
and of Brander. In the propositions of the Directory
of the Academy addresses to the king - those of December
22 1763 that Euler wrote himself and those of July
5, 1764 which he conceived - are relevant answers
to the questions concerning the finances and salaries
of the Academy. It is important to take note of the
fact that in the king's decision, the importance is
precisely to the Mathematics class which Euler managed
since 1744. In effect of the two members proposed
for that class and received the only pensions awarded
of 400 R.Thl. one of them was Jean Albert, Euler's
eldest son.
However, now we can see how the relationship between
the two men chilled by the sudden refusal of the king
to grant a marriage to Euler's future in-law, Cornette
van Dehlen, on December 3, 1763. However, Euler withheld
his decision to leave until Frederick II addressed
the letter of June 16, 1765, in which the king's suspicions
concerning Kohler's financial administration which
until now had been placed under Euler's direction
became suspect. A commission of five members, of which
Euler was certainly a member, was created to oversee
the financial administration of the Academy. Euler
received this as an act of defiance. It was particularly
difficult for Euler to sit on the same commission
with his fellow Swiss and wolffian adversary Sulzer,
whose cautious and punctilious nature was directed
at Kohler.
It was a defining moment when Euler lost the direction
of the Academy. Frederick II who had invited d'Alembert
to take the reins of the presidency of the Academy
had refused but were not handed to Euler even based
on the recommendations of d'Alembert. The king took
hold of the institution himself with d'Alembert as
his counsel. The organization of the king's finance
commission brought Euler and Kohler's collaboration
to an end. Now nothing retained Euler in Berlin.
Frederick II, however, would not let Euler leave
Berlin. His departure would have been a grievous
blow to Prussian prestige with the loss of a scientific
and technical advisor of the first order. On April
15, 1766, the Prussian Directory General thanked Euler
for his report of the national Clevis lottery, and
expressed its hopes to "to keep you for a long
time to come." However, Euler's helvetic tenacity
came through again and at his fourth request, he was
able to obtain a leave from Frederick II without any
thanks on May 2, 1766 and leave for Russia. Frederick's
final request to withhold his departure became a moot
point.
On October 1, 1763, Euler had written to his old
friend Goldbach in Petersburg, " The fact
that the idea of transforming this Academy into a
French Academy still exists. As much as I am upset
at the prospect of leaving, I still must prepare myself
for this eventuality." One can understand Euler's
hesitation, but also one clearly hears the knell,
because what Euler implied was that "a French
Academy" meant an institution where there was
no decisive influences. In effect among the seven
ordinary members named by the king in 1764-1766 to
the Berlin Academy there were seven Frenchmen and
two Swiss, and of the five foreign members named concurrently
they were all French, and notably "hard heads"
like Helvetius for whom Euler had considerable disdain.
The leibnitzian-wolffian following which had been
temporarily displaced, became an issue once again.
In the summer of 1766, immediately following Euler's
departure, the question proposed for the 1768 Academy
prize was a Leibnitz Eulogy. Euler's philosophical
defeat at the Berlin Academy had been consummated.
5.
Euler & Frederick II: The remaking
of a relationship
The two men separated angry, however Catherine
II of Russia an unexpected mutual benefactor brought
about a reconciliation. Frederick II had been determined
to obtain the Empress' favor. He could not forget
the embarassment of the defeat at Zorndorf that the
Russians had inflicted on him during the Seven Years'
War. As of September 10, 1766, he had nominated Catherine
II as a foreign member of the Berlin Academy, after
she had declined the offer to become an honorary member.
From 1763 onwards, Catherine II applied herself to
having Euler return to Russia, without souring or
interrupting the relations between the Berlin and
Petersburg Academies. Euler was the bridge between
both institutions.
It is not surprising to note all of Euler's contributions
to the "Memories" of Berlin from 1766. On
October 14, 1768, Euler addressed the Academy in Berlin
as "Your illustrious Body" and rendered
an account of the works accomplished and proposed
a tighter collaboration between the two academies.
As Frederick II was the real president of the Academy,
the letter was indirectly addressed to the king of
Prussia.
At the beginning of 1776, Euler renewed his ties
directly with the king. Prior to this the king
had distanced himself from a philosophical point of
view from the current of radical enlightenment thinking;
a current arriving from France. It became apparent
to the king that enlightened absolutism was a contradiction
in terms. He held fast to the absolutism which was
threatened by the disaffection of the current enlightenment.
This change of position in relation to the enlightenment
brought Euler spiritually closer to the king. It was
Catherine II's wish to nominate Frederick II as a
member of honor to the St. Petersburg Academy which
provided an occasion for Euler to address the king
directly. Euler profited from the moment by furnishing
the king with some calculations that had been published
in the Berlin newspapers at the beginning of 1776.
According to Euler's work on probabilities there was
a possibility that the calculations could bring about
the failure of a company, which interesting in itself,
Euler warned the king of the corrections in a letter
dated early April 1776. He had already been focused
on the question and had presented the Academy of St.
Petersburg with the necessary calculation for the
establishment of a security fund for widows on April
14, 1769. He thanked Euler for the detail of his work
on April 16, 1776, and persuaded that the purity of
his motives " had made him act". Euler encouraged
by this warmth sent a brochure on the subject in September
1776. The king was overwhelmed by the interest Euler
placed in " his old compatriots" and manifested
his happiness with a letter on September 11, 1776.
Euler having paved the best possible ways for
Frederick II to be proposed as a member of honor
to the St. Petersburg Academy was elected on January
9, 1777. As the Dean of the Petersburg Academy, it
was Euler's charge to write to Frederick II on January
28, 1777 to thank him for having accepted his election
to a position which was the first of its kind to be
awarded at Petersburg. Euler mentioned in these letters
that of the fifty years he had spent as an academician,
half of those years were dedicated to the Berlin Academy
and he concluded with the graceful closing that "
our entire corps is penetrated by the most profound
veneration for His majesty's most sacred person."
When his turn came, in a letter dated February
1, 1777 Frederick II also proved as courteous
by congratulating St. Petersburg for having a dean
such as Euler. Not omitting, but insisting on the
tight bonds between Prussia and Russia at the heart
of European power, he concluded with an eulogy on
the St. Petersburg Academy having achieved, he said,
"with the guidance and direction of the Empress,
a shining and perfection that few academies can claim."
Thus he encouraged Euler to be its leader.
Thus the bonds were renewed, which brought together
one and the other of these two men so different
and despite all of the opposing forces that separated
them.
Eduard Winter
Translated from the French
by J.S.D.Glaus |
