# Ion N Ionescu-Bizet

### Quick Info

Born
4 December 1870
Stoienoaia, Creata, Ilfov, Romania
Died
17 September 1946
Bucharest, Romania

Summary
Ion Ionescu was a Romanian mathematician and engineer. He was one of the founders of the Gazeta Matematica and contributed a remarkable number of articles and problems to the journal. One of these problems is now known as the Ionescu-Weitzenböck inequality. He is also famed as an engineer for building bridges.

### Biography

Ion Ionescu was born on 22 November 1870 according to the calendar in Romania at the time of his birth, but we give 4 December 1870, the date of his birth corrected to the present calendar. We also note here that he was known by the nickname Iancu throughout his life. He was the son of Nicolae Ionescu and Atina Diamandescu. Nicolae and Atina Ionescu had five children, all boys: Constantin, Ion, Iosif, Cristu and Alexandru. Ion was, therefore, the second oldest of the children. Nicolae Ionescu was the administrator of the Stoienoaia estate, about 30 km from Bucharest, which was owned by the two brothers Constantin and Iosif Darvari. In 1878, when he was seven year old, Ion began his primary school education in nearby Carbuneşti. After spending one year at this school, however, his parents decided that, since he was demonstrating such talents, he deserved a better school. He was enrolled in the Clementa school in Bucharest in 1879. This primary school, founded in 1877, was the first in Bucharest to take both girls and boys. He next studied at the Scoala de Rosu nr.1, also in Bucharest.

In 1880, while Ion was still at primary school, the family received a severe blow when Nicolae Ionescu died. A few days before his death, Nicolae, who was being treated at the Colea Hospital, asked to see his son Ion. Realising that he was close to death Nicolae gave Ion advice which would be decisive for his life and career. Let us explain by quoting Ion himself [11]:-
He told me to read a lot and learn well so that I could take care of my mother when I grow up. I understood that he felt that he would not live long and I started crying so I don't know when I was taken home. I kept his word with holiness, for I learned with all my might, and stayed with my mother until her death. I had her as an example of work and conscience in fulfilling my duty; from her I took the spirit of fairness, economy, modest living ...
Now feeling that he had the responsibility of supporting his family, he decided that attending secondary school and then university, which would mean that it would be ten years before he could provide an income, was too long and that he could support the family after five years if he studied at a business school. This route even allowed him to give his family financial support for he won a competitive scholarship which supported him throughout his years at the business school and, by living frugally, he was able to give a part of the money to his family.

During the school holidays Ion Ionescu worked as an accountant to earn extra money and after graduating from the business school, he took a job as Iosif Darvari's accountant on the estate where his family lived. Although he received a lower salary than he had been offered by some firms in Bucharest, he had housing and maintenance provided. This job as an accountant saw him busy in the summer months but having less work to do over the winter. Following his father's advice, he used this less busy time to study hard, reading books on a range of subjects but concentrating on mathematics. After a while his studies began to be aimed at a specific goal, namely to allow him to compete in the recently instituted competition for admission to the National School of Bridges and Roads set up in 1881. This competition aimed at enrolling students of the highest quality to the National School. Let us note here that the National School of Bridges and Roads became the Polytechnic School of Bucharest and then in 1992 became the Polytechnic University of Bucharest.

In 1889 Ionescu took the entrance examination, was placed first and awarded a scholarship. This meant he could study the preparatory year course, at the end of which he took the even more demanding examination which allowed entry to the first year of studies. At the National School, pure mathematics was taught by David Emmanuel (1854-1941), applied mathematics by Spiru C Haret (1851-1912), physics and chemistry by Constantin I Istrati (1850-1919), engineering by Anghel Saligny (1854-1925) and rational mechanics by Gheorghe Kirilov (1845-1908). Ionescu was not only a diligent, brilliant student in examinations but he provided substantial help to his teachers by assisting in writing the course of rational mechanics with Kirilov. In addition, Ionescu worked as a tutor, translated books, and earned money to support his entire family. Of his teachers, perhaps the one who influenced him most was Istrati who was a model lecturer, giving clear presentations, and his style did much to influence Ionescu's style when he became a lecturer. Ionescu graduated from the National School of Bridges and Roads in 1894 with an engineering degree. He received the highest marks that any student had recorded up to that time.

After graduating in 1894, Ionescu was employed as a railway engineer, working on the Cernavoda-Fetesti 21 km line connecting the Cernavoda-Constanta railway line and the new Bucharest-Fetesti railway line. He was already working with fellow engineers on founding a mathematical journal, the Gazeta Matematica, and he made a sizeable contribution to the cost of producing the journal [13]:-
In October 1894, five young engineers Victor Balaban, Vasile Cristescu, Ion Ionescu, Mihail Roco and Ioan Zottu (now considered as the founders of 'Gazeta Matematica'), young graduates of the School of Bridges and Roads in Bucharest (now the Polytechnic University of Bucharest), discussed the poor results obtained by the candidates in that year's entrance examination. In conclusion, it was proposed to set up a Romanian mathematics journal for "our high school students". The name of the magazine "Gazeta Matematica" was proposed by Victor Balaban. He did not see his dream come true because he becomes seriously ill and died at the age of 25.
The first editor of the Gazeta Matematica was Gheorghe Țițeica. Let us note that, remarkably, over the years from 1895 to 2005, Ionescu published 421 articles in the Gazeta Matematica, well over double that of any other contributor over this period. Many of these articles were on the history of mathematics. He also contributed 635 problems to the journal, the third largest number that anyone contributed over that period. Let us at this stage say a little about the best known of the problems that Ionescu contributed. This is the inequality, now known as the Ionescu-Weitzenböck inequality, which states that in a triangle $ABC$ with area $S$,
$4S√3 ≤ a^{2} + b^{2} + c^{2}$,
where $a, b, c$ are the lengths of the sides of the triangle. (Actually, to be strictly correct, Ionescu stated the contrapositive of this proposition.) A rigorous proof was given by N Muzicescu and published in Gazeta Matematica in 1898, the year after it was posed by Ionescu. Weitzenböck's name is attached simply because after he published it in the much more widely read Mathematische Zeitschrift in 1919 it became known as the Weitzenböck inequality but later when Ionescu's earlier statement was noted, it was given its current name.

The first part of the first volume of the Gazeta Matematica was published on 15 September 1895, the day of the inauguration of the King Carol I Bridge over the Danube constructed as part of the Cernavoda-Fetesti line. This bridge had been designed by Anghel Saligny, who had taught engineering to Ionescu. It was, at this time, the third longest bridge in the world, constructed with novelties including a cantilever lattice beam system.

On completing of the Cernavoda-Fetesti line, Ionescu worked on numerous bridge construction projects and other works on the railways. At that time, the metal superstructure of the bridges, which could not be built in Romania, was ordered from abroad. Ionescu was delegated to receive the bridges ordered in France and Germany and, as part of these duties, he spent six months in each of these countries. Returning to Romania, he was in charge of the metal workshops required for completing the Ploiesti-Predeal railway line (1898-1899). On 1 January 1900, he was transferred to the Hydraulic Service in Bucharest, as deputy director of the service. He soon became the director, being in charge of work diverting the waters of the Siret to the Prut. As director of the Hydraulic Service, he had to oversee all major construction projects in riverbeds, especially bridge projects. For example, the railway bridge over the Giurgiu basin was designed and executed under his direct guidance. One of his major achievements as director of the Hydraulic Service was the creation of the Hydrographic Map of the Danube, an extremely accurate map at the scale of 1:10000, including the navigable channels.

Ionescu continued to be one of the main figures involved with the Gazeta Matematica and, in 1901, the journal inaugurated the collection of books known as the Mathematical Gazette Library. The first volume in this new series was "Collection of problems of arithmetic, algebra, geometry and trigonometry", the authors being I Ionescu, A Ioachimescu, Gh Țițeica, and V Cristescu.

The Second Balkan War broke out in June 1913 when Bulgaria attacked Serbia and Greece. Romania mobilised its army on 5 July 1913 and Ionescu was drafted with the rank of lieutenant. His task was to help with the movement of the troops crossing the Danube. On 10 July 1913 Romania declared war on Bulgaria and their troops crossed into Bulgaria meeting no resistance. For his contribution to the efficient movement of the troops, Ionescu was promoted to captain. For his contributions, he was decorated with the Order of Manhood and Faith Grade 1. Again during World War I, 1914-1918, he was mobilised and served at the General Headquarters.

After World War I, he was appointed Director of the Metal Bridge Service on 1 January 1919, and Director General of the Service on 1 April 1921. In this position he led the reconstruction works of the metal bridges which had been destroyed during the war. In 1919 Ionescu was elected as a corresponding member of the Romanian Academy and Gheorghe Țițeica spoke at the meeting during which he was received into the Academy. Țițeica ended his address as follows [6]:-
Therefore, as a distinguished engineer, eminent professor, chosen writer and fighter in the cultural field, Mr Ionescu is considered to have all the qualities to be elected a corresponding member of the Romanian Academy.
We have not mentioned before his role as a professor, but he taught for many years as a professor of engineering. In 1903 he was appointed professor of graphic works and, in 1914, tenured professor at the Department of Bridges. He taught there until he retired. After 1921 he worked as a professor at the Polytechnic School, being from that time on solely a teacher.

Among the honours given to Ionescu, he was elected to the Polytechnic Society in 1899, serving as secretary for 13 years. He was later elected vice president for nine years, and president between 1932 and 1934. To help his former teacher Ionescu, who was seriously ill by 1943, Emil Prager suggested that he print a collection of Ionescu's articles which had appeared in various bulletins and magazines, with the title 'Technical Stories', and give him the income from the sale of the 200 paperbacks signed by him. We end this biography by quoting extracts from what Nicolae Noica writes in [11] about 'Technical Stories' and other aspects of Ionescu's contributions:-
Today, rereading 'Technical Stories', after more than twenty years, I found, once again, the talent and skill of the forerunners in carrying out difficult works ..., but also their seriousness and competence in dealing with the essential economic and social problems ....

Today, the topicality of these technical analyses, made almost a century ago, regarding floods, the navigability of rivers and their economic advantages is surprising. ... Ion Ionescu's description of the Roman Public Works under Emperor Trajan is not only interesting, but also instructive. With extensive quotes from Vitruvius, Ionescu shows that "the engineering and architecture of the Romans required work and studies and that is why they were able to do great works that are admired even after 2000 years."

He describes the engineering work done before and during Trajan's time, so that progress can be seen. The cities had their streets paved with mosaics of large slabs on strong foundations and were provided with sewerage installations that ensured, in Rome, during Trajan's time, a consumption of almost 1,000,000 m/day, of which $\large\frac{2}{3}\normalsize$ was for public services. The water was brought from great distances through aqueducts. In Trajan's time, there were 443 km of aqueducts, of which about 50 km was supported by vaults and legs 32.0 m high, true works of art. Ion Ionescu claimed that Emperor Trajan was concerned with ensuring the sanitation of cities and the health of their inhabitants. About the roads that crossed the empire he says that "they totalled a length equal to twice the length of the equator."

An important road along the Danube ran from Vienna to the southeast to Dacia. Near Cazanelor, upstream of the Portile de Fier, part of the profile of the road enters the rock, the rest of the width was built to be supported on beams embedded in holes dug in the rock. The complexity of the works, the art and the science with which they were made, are noted. 'Technical Stories' highlight the teacher's writing talent, since he manages to present in a simple and attractive way technical aspects that are often arid. In fact Professor of Engineering Cristea Mateescu writes that Professor Ion Ionescu "is the first Romanian mathematician and engineer who had the audacity and passion to spend a lifetime (1900-1946) with research on the history of mathematics and construction in Romania and to write a synthesis of the most interesting works in this field."

University professor Florica T Câmpan writes: "With zeal and self-sacrifice he searched libraries, archives, and erased, as the poet puts it, the 'old column from the chronicle' so that he could paint the 'column of long-gone times.' A meticulous, continuous and passionate work, for almost half a century."

Ion Ionescu was an excellent teacher. He understood that to cultivate the field of science and technology it was necessary to educate the youth and to stimulate them as much as possible. He offered them, therefore, a vast work - spread over 10,000 pages - in which he described, with talent and skill, the history of construction in our country and beyond. Professor Ion Ionescu's contribution to the historiography of Romanian constructions was fundamental.
Ionescu died in 1946 after a long and painful period of suffering. He had a simple funeral and his wishes that no speeches be made was carried out. In his will, he left his house at Rasuri Street, no. 25 to the "Gazeta matematica" Society with instructions that two rooms should be converted into reading rooms for high school students in Bucharest. Although, following his wishes, he had a simple funeral, his friends and colleagues felt that they had to organise a fitting memorial for him. Exactly one year after his death a commemoration of his life was held in the hall which was named for him in the Polytechnic School in Bucharest. On this occasion several speeches were made which praised his outstanding achievements.

In 1995, to commemorate the 100th anniversary of the founding of the Gazeta Matematica, Romania issued a stamp to commemorate "Ion N Ionescu Spiritus rector". See THIS LINK.

### References (show)

1. D M Batinetu-Giurgiu, Inegalitatea lui Ion Ionescu, Revista Matematica din Valea Jiului 1 (2014), 17-20.
2. D M Batinetu-Giurgiu, Nicusor Minculete and Neculai Stanciu, Some geometric inequalities of Ionescu-Weitzenböck type, International Journal of Geometry 2 (1) (2013), 68-74.
3. D M Batinetu and N Stanciu, Ionescu-Weitzenböck inequalities (Romanian),
4. D M Batinetu and N Stanciu, Some generalizations of Ionescu-Weitzenböck's inequality, Journal of Science and Arts 13 1(22) (2013), 27-32.
5. G M Croitoru, Doua premiere la nivel european ale tehnicii romanesti in constructii din perioada antebelica: introducerea prefabricarii la constructii din beton armat si executia primului pod metalic cu o traiectorie in unghi plan orizontal, NOEMA 18 (1) (2019), 239-249.
6. M Gheorghe, Ion Ionescu-Bizet constructorul podului curb de la Giurgiu, Observatorul (16 July 2011).
http://www.observatorul.com/articles_main.asp?action=articleviewdetail&ID=10393
7. M Gheorghe, Ion Ionescu-Bizet constructorul podului curb de la Giurgiu, Giurgiu Net (17 July 2011).
https://giurgiu-net.ro/archives/15985
8. I Ionescu, Problem 273, Gazeta Matematica 13 (2) (1897), 52.
9. G Manolea, Ion Ionescu-Bizet, constructorul podului curb de la Giurgiu, Gazeta De Sud (16 October 2010).
10. M C Marion O extindere a inegalitatii Ionescu-Weitzenböck, Revista Matematica din Valea Jiului 2 (2014), 23-24.
11. N Noica, Ion Ionescu, un lorga al istoriei constructiilor, Historia.
https://www.historia.ro/sectiune/portret/articol/ion-ionescu-un-iorga-al-istoriei-constructiilor
12. M Olteneanu, Ion N Ionescu-Bizet, Asociatia Generala a Inginerilor din Romania (16-31 January 2006).
https://www.agir.ro/univers-ingineresc/numar-2-2006/ion-n-ionescu-bizet_1324.html
13. N Parlog, Gazeta Matematica - 115 ani de aparitie, Descopera.ro (27 April 2010).
https://www.descopera.ro/stiinta/6067449-gazeta-matematica-115-ani-de-aparitie
14. B O Veleku O alta rafinare a inegalitatilor Ionescu-Weitzenbock si Pólya-Szegö, Revista Matematica din Valea Jiului 2 (2014), 22-23.