 These are fancy glasses. Oh, of course. And weapons. Well, good afternoon, everyone. Want me to set that back here? I'm Scott Seaman, dean of libraries here at Ohio University. And it's my pleasure to welcome you to Alden Library and to this edition of Authors at Alden. This afternoon is a collaboration between the libraries and the Department of Mathematics without whose support. This afternoon's event wouldn't be possible. So we thank them very much. Dr. Ronald Kalinger has joined us this afternoon for a discussion of his latest book, Leonhard Euler, Mathematical Genius in the Enlightenment. Euler, who lived from 1707 to 1783, was a Swiss-born mathematician, physicist, and theoretical astronomer whose work was influential in mathematics, rational mechanics, optics, astronomy, philosophy, religion, and music. Dr. Kalinger is an expert in the history of mathematics and sciences from the 17th through the 20th centuries. He earned his BA in history and mathematics from Ohio University right here, his MA in European history from the University of Pittsburgh and a PhD in the history of science from the University of Chicago. He has authored and edited eight books, including Classics of Mathematics, Vita Mathematica, Historical Research and Integration with Teaching, and in 1999, a Contextual History of Mathematics to Euler. He is currently Professor Emeritus of History at the Catholic University of America in Washington, DC. In 2001, Dr. Kalinger co-founded and served as the first chancellor of the Euler Society, an organization created to encourage scholarly contributions, examining the life, research, and influence of Leonhard Euler. Its members have founded the Euler Archive, which contains almost all of his published writings. Our interviewer this afternoon is Dr. Bob Klein, Associate Professor of Mathematics and Mathematics Education here at Ohio University. This discussion will be followed by a question and answer session. So please join me in welcoming our two speakers. Welcome. Thank you. So welcome back to Ohio University. It's been a while since you've been back. Would you like to say a little bit about what being a Bobcat has meant to you and coming back? I mean, there's no Jake's hamburger anymore or Angelo's pizza, but OK. Well, first off, I'd like to thank everybody for coming out to hear this presentation and to say it has been so great. The library and Dean Siemens have done exceptional work in Bob of welcoming me back. And it was actually one of your people who was no longer here at the Ohio University who wanted me to come back to visit. And Doug, when he said he wanted this, you did it. So I was very happy to come back. And it took me a day that I hope it's not terrible, but I now feel like I'm an Ohio U student again. So it does work. So what brought me back was the order book came out and some people, different people have asked me to make presentations on it. And let us say, I think it has gone better than we had hoped that I owe debts to a lot of reviewers right now. And so since Doug had asked me to come to Ohio, I said, and since I knew that Ohio U is ahead of things in that you have somebody in the history of mathematics which most people do not have. And I think every top school should have somebody in the history of mathematics. So it was also a pleasure to see that. And then once the invitation was out, the fact that I've met so many students so far just reinforced that I should be back talking to the students. When we appreciate you bringing back the nice day too. So thanks for that. It's only getting warmer, right? So one of the things that struck me when I was reading the eulogy that Nicholas von Puss gave for Euler was this very first sentence. And I thought it was a fitting way perhaps to introduce to people who might not be as familiar with what makes Euler as great as Euler was. The first line reads, to understand the life of a great man who has exemplified this century by enlightening the world is to eulogize the human spirit. Could you comment a little bit about how it was that he exemplified his century and about that enlightenment and his contributions? Well, let me add just one thing to that. That was Nicholas Puss. There was another fellow who said the same thing and his name was Emmanuel Kant. And so, but the mathematicians have a disagreement with Kant over several issues, so they usually don't use that. What you have is something in the 18th century in Europe, something called the Enlightenment occurs. And it's a time of new thinking and a critical spirit so that you have to have new thinking but there has to be criticism. You have to be able to justify things. And so, Euler is unusual. I mean, his energy is phenomenal. He wrote 850 articles. He wrote 18 books. He doesn't write a small book. He and I are together. All of his books are like 600 to 900 pages. And so, Euler has done this. Now, one of the things that I would disagree with some of my colleagues today is Euler is one of the four greatest mathematicians. Archimedes, Isaac Newton, and Carl Friedrich Graus are the other three. But Euler did more than all of them but he wasn't the first. He didn't invent the calculus. He invented all of its branches, all of its chief branches. He was a chief person on the calculus of variations, on the integral calculus. All of that is his work. His astronomy was brilliant. It stood up for 200 years. His works in physics can still be read today and people get equal understanding. It's not like you're reading something. One of the things that I was doing was reading one of his books called Introductio. So, Introduction to Infinite Analysis. And in that book, I was reading through it and I did an English translation and I thought I was reading a book that was just written yesterday. It just is amazing that he could do this. So Euler was able to invent all these fields in mathematics. While people don't know him, you couldn't get to the moon unless you had his optimization theory. You couldn't have things about the tides unless you had his tidal theory. It is amazing, all of these things that he invented. Compound interest. You can do compound interest very simply with a letter called E that he, well, he didn't invent Bernoulli and Newton did that. So, he did all of these things that have made life possible as we know it. And yet, outside of mathematics and sort of I partially blame mathematicians for this of not speaking to people outside their own group on that. And I think that that will be possible or I think that will be very advisable in the future. But Euler did, so all the fields that you recognize, one of the things I'll give you where Euler made mistakes. A lot of people like to say he never made a mistake. He was always right. Where was one of the mistakes? He said the world was going to end in a few thousand years and it was going to, the earth was going to fall into the sun. And so, if people just read that, there are some and say, oh, well, he was wrong here. Well, why was he wrong? He took astronomical observations that have been made in 300 BC, in 300 AD, and in 1700 and he felt that the earth's orbit was falling closer towards the sun. The fault was not that he was wrong. In theory or the like, it was he read the data and the data was wrong. And in that case, he didn't come back. So several times you'll find Euler will make mistakes and but that doesn't stop him. As a matter of fact, he throws out every new idea he can and some mathematicians have criticized him for that have said that he was reckless, that he shouldn't have put this. See, a fellow named Carl Gauss would not put anything out until he had everything proven. Euler would put things out because he instinctively knew what the right answer was and that he would then find the way to get there. And he was almost always right. As I say, he had it. So if you look at Euler, if you look in the physics at the time, if you look in the mathematics at the time, if you look in the shipbuilding, he has the superior designs for ships. If you look in the superior telescope, he has the superior telescopes, all of these things. None of that would have been possible. And I would say that Nicholas Fuss was aware of that. Nicholas Fuss spent his last 10 years with Euler. He lived at the Orders House in St. Petersburg. So, but Euler has done all these things. Even if you disagree with his music, which many people do, because he tries to make it too mathematical, as his critics say, it is out there. It is one of the major theories. So, look down all the scientific fields in his day, and he has advanced them, I would say, by a few hundred years on that, that he has come up with solutions. And Isaac Newton is the great scientist, also from this period. And Newton every once in a while would say, this is the answer. And you'd say, you can't get that answer unless you have differential equations. And Newton, you don't have differential equations. So, he knew what the right answer was. And so, order would, so he would give that answer only in a few cases, but order quite often would say, okay, this has to be the answer. Disprove me if you can. And usually, he was not disproved. So, he used the word genius in the title of your book. So, you've got this genius, this mathematician who is so prolific, perhaps most prolific of all time. And I think there's a stereotype of this level of genius of being wildly eccentric, the loner hermit. And yet, in some ways, it seems that Euler countered those stereotypes, or lived in a way that would challenge those stereotypes. Well, my view is that in the first instances, the scientists and the mathematicians do not have many biographies that are giving the full dimensions because, for example, when I was writing this book, I sent out and said, I was reading the correspondence and Euler was asking about how is your wife, is your family healthy, how are your friends storing? And I was writing that into the notes for the biography. And some mathematicians wrote to me and said, don't say that, who cares? You know, we don't want to know how he did his mathematics. And I don't, I think that's a mistake there. So, what I tried to do was Euler is just the opposite as Bob just said of all the sort of images. Euler had 13 children, five of whom survived. He had a very happy marriage. His wife was exceptional, Catherine. And so, she took care of everything so he could do his work on mathematics. So, when she died, the family said, how are we going to keep going on because she did everything around the house with the family and she kept everything going well. He, as I said, he had five children. When in 1753, his mother moved from Switzerland to be with him. And when she moved, he moved his family, his children out with his mother. So, the children did not live with him after they were like six or seven years old on that. And, but he loved to take the kids to the zoo. He loved to see the bear cubs. He loved to go to marionette shows. He was famous for laughing at all the things that went on as you saw on these shows. So, as far as I can see, he's just a usual person once he goes out. The only person who was unhappy with him was Frederick the Great, who was there because order did something which mathematicians, and I think some scientists do, that they take a little notepad with them and they're at some important place in the show and they think of an equation and they take out their pen and they write it down. And, Frederick said this, these were the sons of Euclid. This was quite disturbing and order had to stop this immediately. So, order kept it up, but Frederick was not happy with that. So, he did things like that. He worked with other people. One of the things they like to say is these people were isolated. Five days a week, he had what he called a round table in Berlin and in St. Petersburg. And he would have eight, 10, 12 people there and they would have lunch and they would talk about what was going on. They would talk about proofs and I will say the only criticism I saw was of some Russian students who lived with him because, well, I shouldn't, well, let's say they drank too much and so order said, let's be more reserved about that. So, order is definitely not eccentric. He's definitely not isolated. He definitely does have a sense of humor and he definitely loves history and he writes everything and if you read it, he has a book or three volumes called Letters to a German Princess and part of that is really a history on that as you go through that. So, it's one of the things, one of my friends wrote the biography, the best biography of Isaac Newton. There have been subsequent biographies and I can't understand this because the subsequent ones are not nearly as good as Sam's biography. But Sam studied Isaac Newton and after 20 years, he said, I don't like him. He said, I study him all these time and the things that he's doing in religion, this, that and the other, I can't abide by that. But it didn't stop him from writing an outstanding biography. I studied order for more than 20 years and I still like him so he would be a good guy to have at a dinner party. He would be a good, if you were trying to solve a problem in mathematics, he would be exceptional. So again, I think he's just a good, well-rounded figure and I think many of the top mathematicians are. So he sounds very good natured. One of the things that I really appreciate about the book is Ron's excellent at including a wide context of the historical context, the things that are going on during the time, not just the sort of mathematical narrative and the time at which Euler goes to St. Petersburg to the new Imperial Academy is a time of great turmoil. There's a lot of political squabbling, it seems, between the reason versus faith and the Newtonian versus the Leibniz and the pietists and all of that's going on and having just gone through the tenure process as a young faculty member, I can't imagine walking into that and so how did Euler navigate all of that political squabbling and to what extent did his upbringing in Basel and his theologian father and that community contribute to his overall demeanor or way of interacting with that or dealing with that? I will give much of the credit to his grandmother and he lived from the age of eight, he lived with his grandmother on that and so he would come home on the weekends on that from Rien, which is right outside of Basel. He, well, he had one advantage to start with and that was he was the most Bergen person around. He was always 10 steps ahead of everybody else. If you see a problem, you'd say, well, this could happen, this could happen, this could happen and he would be way ahead of you and he would be knocking down the arguments. So, but Euler had one view that applied here and that was don't get into arguments and he did not appreciate having the sharp argument. So if the Newtonians were against the Cartesians, as a matter of fact, at the Imperial Academy, Daniel Bernoulli was a fellow for the Newtonian and a fellow named Bolfinger was for the Cartesians and they would yell at each other and as a matter of fact, the head of the Academy had to order them to stop yelling at each other on that. Now, Euler never did that, there's never a thing there. Now, Euler, to show you that he does work, the only thing he complains about and nobody would understand this at universities, he thought he wasn't being paid enough. So he thought that scientists should get more money. So anyway, he did write the letters and the one letter was, but it wasn't a nasty letter, it was, here is what I have done, this is what the French do, this is what the French get, this is what I get. And there was no comparison, so that was good. But he didn't get into arguments, the interesting point was, the Russian Orthodox Church was against Copernican astronomy and so some of the critics, there's a fellow named Cantamere who is against the clerics. So in essence, when he writes, it's the clerics are a bunch of fools, the clerics you can't trust, this is terrible. That's not Euler. Euler writes out and says, well, you know the scientific basis for this is the following thing. And really, everybody makes mistakes. We scientists make mistakes and he doesn't say that they're making mistakes, but he just says, I can give you a lot of examples of mistakes we've made in the sciences. And what happens is, Euler's accepted on that, the clergy accepts him. Euler is very devout, he's a reformed Protestant which is not Calvinist, but it's close to Calvinism. And he is pretty much very even keeled. There's no time I know of it. The anytime he becomes angry is in correspondence and he becomes angry with a fellow named Jean D'Alembert. Actually, D'Alembert's probably right on that. I hate to disagree with Euler there. They're arguing about fluid mechanics, but that's the only time I really know him to become angry because you see the letters of, you know, we said this, this is what happened, and I did this first. You didn't. Well, then two years later he wrote and said, my apologies, you actually did it first. So he was man enough to admit he had made a mistake in that. So again, I think the fact that he's able to work with others and he works with a fellow named Christian Goldbach that's for the mathematicians and there's a big debate about how much Goldbach contributes and my view is the Goldbach contributes a lot but he's there with Euler. He's not anywhere comparison with Euler. So everybody who knows Euler in Russia pretty much knows him as being a person that they can get along with. Now one of the things in trying to change what I think is misinformation, people who wrote about Euler in the past said that he was in the Russian Navy and I find no record of that and people who've written about Euler in the past said he was offered an officer's position. I find no evidence of that but he did work with the Navy and he did work with their maps but he was never offered a job in the Navy. So when you read through my book we go through that period and we don't stop for that explanation. So 20 years and 600 plus pages later seems like you would have looked at a lot of evidence. Can you talk a little bit about the process of going, I assume you've been to other libraries, lots of libraries, so what is the evidence? What does that look like? We have some students from our history of math class out there that might be interested in knowing what the professional study of that looks like. Well, when you're looking at the history of math for that period on that there is a rich collection of materials. Of course the Euler's Oprah Omnia which has volumes 300 to 600 pages each which has over 80 volumes so far and it has two or three more volumes to go. Euler wrote 40,000 pages published publications. So if you're into that, this is when I went to graduate school in Chicago there were two places that I went to. One was a place called Harper Library and they had not yet broken out into archives and special collections. Everything was out on the shelves and so the University of Chicago had all these 18th century books and so I went and my hands turned red and my shirt turned red and I went up to the librarian and said, is there something we can do? And they said, yes, we can give you a white coat and you wear that coat and you wear these gloves and you go through those and I said these all should be in the rare books room and it was only after that that the University of Chicago went to the rare books room. So we went first to find the general books and then what happened was I started out not on Euler but on the 19th century and I was going to work on thermodynamics and I kept finding, I kept going back to Euler every time I say this equation is from Euler, Euler did it this way, Euler did it that way and so if you could do, there was a fellow named Truesdale, Clifford Truesdale and Clifford Truesdale brought out five volumes of the Euler-Oprahonia and so Clifford was, now if you talk about an eccentric, he was an eccentric but he was an eccentricist, a mathematician physicist, I'll call him, he was at Johns Hopkins. So anyway, you went to these two libraries, Harper Library and then at the Math Library and there was one nice thing the Catholic University does is if there's something out there, they'll get it for you. I mean, they'll pay thousands of dollars. I mean, they just got me a book that I really want to read and it's some of Order's letters that I haven't seen yet and wasn't in the United States, wasn't in Germany, they found it in Switzerland. They paid to ship it from Switzerland to Washington DC and to have it. So in looking for these things, it's very good. My view is just go to the libraries especially if you're in the history of mathematics and you'll find out that many of these things have not been read or have not been used and they're just sitting there on the shelves and I would say the Order's Oprah Omnia, I think I was one of the first at the University of Chicago that would be pulling them out almost every day on that and so you can do that but here's the warning that I would give. In the Order Oprah Omnia, it gives something called the letters to a German princess. That's one of the, it's in series three and if you read that, you know what he said but then right before I wrote this book, I went to the Smithsonian and the Smithsonian had just gotten some of the original letters from the first edition from 1768 to 1772 and they put them in on the desk for me to use and when I read that first edition, it was different. I don't know what it was but when I opened that book, I saw things that I hadn't seen before on that and so get the first edition whenever you can on that. So those libraries, the Basel University, their library was helpful. The St. Petersburg, when I started out, it was the Soviet Union and it was Leningrad and I wanted some materials and the University of Chicago, I couldn't believe this. I said, I want this document about order and so they negotiated and the Russians demanded the first edition of Uncle Tom's Cab and they wanted the first edition. They wanted books that would cost a few million dollars and the library came to me and she said, I hope you don't mind. I don't think I'm going through with this and I said, you shouldn't even consider it, I would think and so that was the only time that we had and we found out that the Agriculture Library in Washington DC had some of these papers which almost nobody knows. They're out there in the library. So go to all the libraries. I think there's only one librarian in 50 years that I thought was not extremely helpful on that and everybody is, it's just, I mean one librarian I came through and I was trying to find something from 1912, a German magazine and the reason I couldn't find it was that it got out of business and so I was trying to see if I, so I talked to the librarian at the University of Maryland Engineering Library and he said, I'll have that for you and I said, well, you know, it's been very difficult and he thought I was a faculty member there but I said I wasn't and he said, doesn't matter and so that evening I had all the information he had gotten it for me so. So go to the different libraries. You never know for the history of science if you're in Washington DC go to the Dibner Library at the Smithsonian which is very good because if you're having lunch, if they know, Bern Dibner used to make chili for my students. The students would go to his library, they had a library in Connecticut and he would invite people to come there and he would always say come about noontime because I'll cook and so he always did that. So the Dibner Library is very good. It's now at the Huntington. It was at MIT but Huntington out by Cal, well by Stanford is where you want to be. Wonderful, you may have hinted at this before but with all of that research in the 20 years and digging in were there any major surprises along the way, things that you hadn't expected or hadn't known? Well it's sort of I think somebody just wrote, I thought an excellent book review in the New York Review of Books and half of the review was what does the author like? What does the author expect to do that? I will say I expected there to be mistakes and I found a lot of mistakes. Like I said, there's one thing I have here is a picture of something that never occurred which is anyway there's a book that will be, I think it is about here, it's probably, there are several mistakes. I will say there was a mistake that he was in a boat had. It was getting some sun. Oh, it was getting sun, okay. Well this is the boat, well this is supposedly the boat and this is Euler Returns to Russia from Berlin in 1766. And so the Swiss government I think paid $800,000 to do this. To the people that do the research. There's a major problem. The pictures inside are excellent so I think somebody here could use it on that. And what is, a fellow named Frederick the Great wrote a letter to a friend and said, you know Euler was going back to Russia and the boat sank. And luckily it was two boats and the second boat had all of these books and it all has the unpublished books and gee we're all being spared of having to read that stuff. And so the Swiss unfortunately read that letter and said ah we're going to beat everybody out by we'll break the story. Well they broke the story. Unfortunately the story is wrong. And so one of the things you have to do is to be sure your information is correct. I can't, I know the fellow in charge of this Martin is a fine historian. I don't know how he ever did this but anyway I think it was the excitement of the moment must have gotten to him. So anyway there wasn't, I don't think there was anything that I terribly didn't expect. I will say that I did expect him to be interested in different fields. I did expect him to get along with people. And I was being told no that wasn't true so I was using that approach on my beliefs. I would have been shocked if it had come, if I had gone into that and found out gee this is exactly what is the case. So but I found out all sorts of little information about him and his family which is wrong. Well like the one thing of his having these daily round table discussions at home and where he brings students in and he teaches them and he likes, he loves to teach. He writes, he writes in math education you would probably be using his books but he wrote a two volume basic mathematics that you need to use. So he does all of these things but all the things that I expected he did on that. And I, but again I think that goes back with whether I thought he was going. And maybe it's one person said it's because you're an historian that a mathematician would not accept that or an astronomer wouldn't accept that. But I do. Interesting. Do you want to say a little bit about, he's one of the more famous blind peoples in history. And I think you told me last night that he never, like he admitted his blindness very late in life. Yes. He as early, he was born in 1707 and as early as the 1730s he had problems with his vision but he really had the cataract that was doing in his vision about the 1750s. So for those of us who've had cataracts and had that operation we know what you can see and what you can. So his vision was getting worse and when he went back to Russia his vision was he could read a full page and he could write letters large but he couldn't write the smaller letters. And so at that point he still does his research. I mean this fellow, the energy he had is phenomenal. So he did that but he said when he became blind was the last day of his life. He met a friend for lunch. The friend had come to his house, a fellow named Lexel. He came to the house and ordered or ordered or talked to him and said today I am finally totally blind. And that was the first day he had done that. But from the 1760s, let's say 66 because he's still doing great work in the early 60s and I don't want to give him any advantage but he continues that great work into the 1770s. So he calls it, he says I have one less distraction and the distraction was being able to see. So he did that, yes. Blindness, nothing pretty much stopped him. And as I say this is where his wife comes in on that. His wife sees that everything is set up, everything's taken care of. And at the end, Nicholas Fuss. Nicholas Fuss will read all of his mail to him, will read the newspaper to him and he will take dictation on the letters. Orner had 5,000 correspondence. So there was one of the theories which I disagreed with was that Orner was isolated. Well no, he had 5,000 correspondence. He knew what everybody was doing. He wrote to all the universities in the German East. He wrote in Holland. He was offered jobs in Holland. There was one job he would have accepted which he was never offered. And the job was he wanted to be a Cambridge University. That's a, he wanted to be a member of the Royal Society and they wouldn't, he kept hinting, you know I will take this and I'll send these books and all that. But no, that never happened. So otherwise he turned the Dutch down because he told the Dutch offered him a job and he said I will accept the job if I don't have to teach while I'm doing my research. So I can spend a year on my research then I'll come back to teaching. And they said no, you have to teach regularly. So there, but that was usually how he handled things at that point. Wonderful. So at this point, perhaps you all have some questions that you'd like to direct to Dr. Callinger. Sir, I'd be happy to moderate those questions. Dr. Drabel. Okay, the chief. And could you repeat the question? Okay, would I comment on the mentors that Euler had and the chief people that he influenced? Now for the mentors, the person really has to be Johann von Bernoulli. That Bernoulli thought that Euler was the greatest mathematician he had ever seen. Euler was an 18 year old student and he already says he's the greatest here because Johann Bernoulli had his son named Daniel Bernoulli who was one of the greatest scientists of the 18th century and he pretty much said Daniel, you're not in Euler's leg. So Euler tried to keep that down. That was one of the things of how he got along with people. So Johann Bernoulli would be the one person that I would look to. There's a fellow named Jacob Herman. And that is, Herman was in St. Petersburg with Russia in Russia for two, three, for three years with Euler. And so an Euler would go to his house and obviously they were working on the mathematics. And so Jacob Herman was the fellow who said, we need analytical mechanics, no more this geometric approach. And so I would give, those would be the two people I would give to his father the religiosity that he goes into. All of his life he says the same prayers at dinner that his father taught him on that. So after dinner you had to have those prayers. Now his grandmother, as I say, I think is really important there too. So those are formative influences. He has a host of people that are going to come out who will be influenced. There's a fellow named Lexol, Anders Lexol who is one of the greatest astronomers of the 18th century. I think in most societies nobody knows him. He's finished. So Lexol is there. There's a fellow named Rumovsky who's a great astronomer. Euler influences him. There are not directly, but Lagrange is going to be influenced by Euler. But his is directly, I was thinking of another name. So those would be some of the greatest. There is a fellow named Segner also is great. And Segner is really, now if you want to have an eccentric, strange mathematician get Segner into that. Segner is invited to meet Frederick the Great the head of pressure and he comes dressed as a bear. And so he goes through the interview of this. And so Frederick says, who's the greatest mathematician? And he says, well, Newton is probably the greatest. And he says, who's the second greatest? And Segner says, of course I am. And so Frederick has to leave the room at that point and says somebody else has to hire. And Orner said, hire him, he's a good mathematician. Doesn't matter what he's doing there. So those are some of the people. But if you go through the Berlin Academy and if you go through the Russian Academy all the way up through 1850, you will find people that were influenced. But the ones that I just gave, I think are the chief ones. That's other questions. Dr. Goli-Sashvili, and I'll repeat your question after. So the question was, can you repeat that for me? It was Calvin. And Swingly. Okay. So we're into the religion of the time. Orner is not influenced by Swingly. Swingly was opposed to music. And Orner loved to play the clavier. And so, but he was influenced by a fellow named Ocho Lompadius who was the religious leader of a previous time in Basel. So yes, this is the time of reform Christianity. And Orner moves closer to Calvin. So as he gets older, most people will say he's a Calvinist onto that. And what his big difficulty is the Protestant groups are fighting one another. And so, for example, when he's in St. Petersburg, he has the Protestant groups come to his house and says let's talk this out. Let's resolve this issue. Doesn't happen. They leave and say we won't do that. So, but no, Swingly is not. He is a reform, Orner is a reform Protestant, but he does music is very important to him. And again, theologically, he only writes two things that will get you close to his religion. One is the rescue of divine revelation. And that's in 1747. And then several of his letters to a German princess deal with religion. And so, I would say he's somewhat independent but he's a reform Protestant. And, but he won't go as far as Calvin onto that. It gets strange because some of the people who Orner would support were killed. And supposedly, I don't think the term religious should ever be applied to these groups. But back in the 18th century, they were fighting in places like Switzerland and Orner would have nothing to do with that. Other questions? Yes, over here is a question. Ah, yes, Sherry. Oh, okay. There's something called the transit of Venus, which I hope that Ohio, you had a few years ago. But every about 120 years, the planet Venus goes between the sun and the earth. And so, when you, when you, so that's going to fall. Ah, so I'll hold it at this point. So, if you, so that happens. And then eight years later, it happens again. But the planet wobbles. So, it only happens about every 120 years. And then eight years. And then another 120 years. Now, most campuses had the transit of Venus. I went to the Johns Hopkins one. Columbia had it. University of Chicago had it. Harvard had it. And you get to see the, the planets going. And you get to see the planets coming in and it's a little dot. And so, what Johns Hopkins had was 16 of the best observatories on this, on the planet. And they had everything up on the screen that you can see. And there were about 200 of us who went there. And when that, when that little dot appeared, the audience included high school and middle school students. They started cheering and applauding and jumping up and down, which I thought was a good way to handle that. And we had, Johns Hopkins had the fellow, I consider the most brilliant person on this planet, was the fellow who was at the, his name is Reese. I can't even think about how brilliant he is. Although, he only speaks simply. It's just, you give him an astronomical problem. He will see through it, where others will not be able to work into it. So, the transit of Venus was, was very important because for the first time, when we talked about how far was the earth from the sun, it was always astronomical units. We never talked about earth units. And so, when you do the transit of Venus, you can do the transit of Venus from one observer is up by a pole, one is down by the equator, and you have that in your triangle. And then you do a triangle out to this way. This was the first time they were able to say, the sun is exactly this many earth miles from earth. And Euler was the one, was one of the people who did that. I will say, he did order all of, he was blinded or nearly blind at that point, but he ordered all of the telescopes from England. He said that English had the best telescopes on that. And so, the transit of Venus was, is a very important development in the history, but you'll have to wait 120 years if you want to see it again. But yes, he was the one, he sent, one of his sons was sent out to Siberia, one of his sons was sent down to, I think Georgia on that. And so they went and they made their observations and they came back and then he got observations from Peru and the like. And then he did these, again, of having earth measures. And so for the first time you have the earth measures. And I would, some people say that's the most important astronomical discovery of the century. I don't totally accept that, but it's one of the most similar and quite clear. Of course, they discovered new planets and all that. Dr. T's from physics? Well, if you read the order over there, that's one of the issues that is addressed. So I like the question, it really, it really happened. So the question was how many languages do you have to read to, okay. Okay, oh, okay, sorry. The, you have to know Latin and you should know French. You're okay if you have those two languages. You can get the sense of Euler and then you go from German from there and then you could do a little Russian. You can even use English. Euler made one major English translation. And so the fact that it's easier to translate it that way into your language, but I would say that Latin and French are most of his articles are in Latin and French. I don't have the exact percentage, but it's like 80% of his writings are there. And, but in today's world it's, if you want to know what's going on in some of the most interesting studies, they're in Japan, they're in China, and you have to be aware of the Japanese are really moving ahead in this area and I expect them to come out with a great scholar very soon. Of course the Russians are constantly into this area and the Russians, I visited once and the Russians came, drove from Moscow to St. Petersburg. They said it was a difficult drive, but they drove into there and they were doing all the studies of Euler. And what the Swiss want to be done is they want somebody to write a definitive book on Euler's work in astronomy, Euler's work in mathematics, Euler's work in shipbuilding, Euler's work in telescopes. And once experts in each field has written, then write the biography. One of the comments that was made to me was you can't write the book because you have to do that first on that. So one of the things, if you're writing a book, you sometimes have to take, jump off the edge, there were people will tell you you're not allowed to do that or you can't do that. And I will say this, the Swiss and the Germans are very, and I think the Russians are, the greatest Russian scholar of Euler is Gleb Mikhailov. And he's about 85 years old now on that and he made comments on the book of, be careful on this and be careful on that. And I don't know if Russia will have another scholar nearly as good as he is on Euler. None that I know of anyway. Other questions? Yes, sir? I'm curious about the... Yes, yes. How many books does this for a lay boy? Well, first off... So how do you tackle 850 articles and synthesize that for a laybook? Okay, well, first off, you plan to spend at least 20 years working on it. And then you make notes of, this is a new thought, this is something I haven't seen before. There's almost no repetition in Euler. You just keep reading. And all of his articles, as I say, are like 30, 40, 50 pages long. But the thing is, it's like reading a modern physics text or it's like reading modern mathematics. But if you read, his Introductio has been translated into English. And I challenge people to read the introduction. And at least if you're like me, you'll say this has just been written on that. So you get to see that. Now, there's a lot that's going to be there that's not going to be covered on that. So what we do is we've covered, I think, all the major areas. And I would say, for example, my Russian friends said he's an astronomer. Don't you let this get away without saying he's an astronomer. And they were very insistent on that. He's a theoretical astronomer. That's all false when they say that he wasn't important in that. And so same thing. So then Gleb Mikhailov came on and said, no, he is a mechanist. He is not a mathematician. And so I said, okay. Now I agree with the Russians on this. Not that I agree with their explanation, but I think it's a good argument. And they said, order really didn't like mathematics that much. He really loved mechanics and physics. And that's what he really was into. And he just did mathematics to help him get over some questions onto that. And that's the Russian position there. I didn't take that in the book on there. I still am going with the old fashioned one which says that mathematics is, at least from what I, and maybe I don't understand physics well enough to know. But I do know that my doctoral advisor when I was writing my dissertation said, Kalinger, I want you to work on mechanics and calculus. And the fellow's name was Saunders McLean, was a very fine mathematician. And he says, maybe that mechanics is more important. And I thought, he knows a lot more about this than I do. But I hope when somebody comes back, one of the things that I wanted to do was to write a book that would stand up for 20 years or so. That 20 years from now, people won't be saying, oh, forget that, we don't want to do that. Well, this book, the first reviewers, I'm hoping they're right. 20 years is a short time span, according to the reviewers. They think it's gonna be 50 years on that. So I won't see that, but somebody will see how that goes. And that was the, again, you just keep reading, and you keep going through, and you keep talking to the experts. And you get, like, Gleb Mikhailov, as I said, is just one of the outstanding Russian scholars on that night. And Martin Matt Mueller, I mentioned here, but he's one of the best scholars on that. And Ian James, another one, he's at Oxford, one of the best scholars. And I would come back. And even Saunders-McLean, when I started, he would every once in a while say, you know, Kellinger, a mathematician wouldn't say it that way. You have to say it this way. And I would say, okay, that is fine. And I can tell you, one of the Swiss astronomers, one thing he said, no, you have said that. An astronomer would never say it that way. And so then he said, and then I've gone along with him. He said, you have translated order from the Latin and you did it literally, but that's not true. An astronomer actually means just the opposite. And so I did the opposite in the translation, but I won't tell you which one it was. But it's, everybody's going to be making. So the ones that I had a great deal of confidence in that I thought and I would say there, I couldn't believe on the back of the book are some recommendations. And Craig Frazier is one of the best historians and mathematics around today. And I couldn't believe he was pleased with that book on that. So one thing I can tell you is, if you translate any Latin, the Swiss and the Germans will tell you you don't know what you're talking about. And so every time I've done that, and as I said, I did the one translation with the astronomers. It just, for some reason, the Swiss just wrote and said, you Americans don't understand Latin. And I thought, maybe we do even better than you do. I don't want to get into an argument with that. So again, if you go with the people that you really have faith in and you look through as much of the material as you can, it, and Euler is, Euler stresses clarity. And so when you read through, there aren't these really complex issues on that. So you can read through and say, yes, I understand what he did there. Yes, I can understand that he solved the problem because I can understand that's pi squared over six on that. So for a mathematician, that would be simple, but there's a little thing about one plus a fourth plus a ninth, now what does that equal? And it equals pi squared over six. And the order does that. And my view is he makes, he does two things which he shouldn't do, comes up with the right answer. And so my view is he was calculating pi and he said, I really think this value of pi has something to do with this. And all of a sudden he got the answer. And he had, you get a statement from him, suddenly his fever went up, the excitement, the rush, when he found the solution on that, which people have been trying for a solution to what is called the basal problem for a hundred years, and he did it. Wonderful, so as moderator, I'm gonna claim the last question. Dr. Kalinger will be around to answer your questions for a little while, I think, after this. But so Friday would be Euler's 309th birthday. I guess I wanna know, how are you celebrating? Well, what we usually did, I used to say with my classes, we would have an Euler birthday party, which I think everybody should have that. And we usually had linser torta and sacro torta, which are very popular desserts, and usually some soft drinks. And it was, we always got 50 to 60 students to come in for that. But yes, that is the thing, I will be on my computer to Martin Matt Muehler to wish him good sailing with the Euler Center there. But yes, we will not be having the big celebrations, although I don't know. Well, I know two people who may want to have a celebration, so I will wait to see them. There's two people who work with the Order Society who are going to do that. There's one fellow who actually is responsible for the Order Archives. He did more work. Actually, this is the other thing of who do you work with, and he went to a university, one of the top universities, so now it's going on, that he got the math department to say they would support that on that. And so this was wonderful. So the celebration will be quieter than usual. We're waiting for a big year. I can't imagine a better thing to do on tax day. Oh, okay, well luckily that's been done. So we will wait to see that. Thank you, Scott. Well, please join me, everyone, in thanking Dr. Callinger and Dr. Callinger. Or Dr. Callinger will be with us for a few more minutes, so if you have any questions, please feel free to come up and ask. Also, there is an exhibit that is happening in conjunction with this talk. It is titled Beyond Numbers Stories in the History of Mathematics. It's right in the lobby, and I'd encourage you to take a glance at the materials that are there. So once again, thank you, Dr. Callinger. Thank you, Dr. Callinger.