DOPPLER, Christian

D. was born as the son of a stone-mason. He had a talent for art, so his father already at an early age sent him to the cemetery, where he would watch statues of angels and produced clay statues similar to them. These later served his father Johann D. Evangelist as a model for stone statues. In addition to working in his father's workshop, D. in Salzburg, which became part of Austria-Hungary in 1816, attended the first three classes of "German school" between 1816 and 1819. When his father realized that his son was physically too weak to work in his business, he requested advice about son's education from mathematician and land surveyor Simon Stampfer who at that time taught in Salzburg. After Stampfer noticed the ability of young D., his father decided he had to continue his education. D. in 1820/21 finished the fourth class in Linz and then more than two years studied natural science at the Polytechnic Institute in Vienna. Upon completion of the study he wanted to become an assistant to his teacher Josef Hantschl at the Institute, but was initially unsuccessful. While completing his general knowledge in Salzburg he from 1824 onwards attended grammar school and began studying philosophy in 1827 and parallel to that taught mathematics and physics at the Lyceum. Between 1829 and 1833 he worked as an assistant for higher mathematics under Adam Burg at the Polytechnic Institute in Vienna. At the same time he also served as a public tutor of elementary mathematics as he did in Salzburg before. In the following years he was looking for an academic post, so he had to attend the so called courses, where they checked knowledge of the rivals and also evaluated their lectures. At first D. could not establish himself in these courses, which was not infrequently the case. A high ranging in these courses was considered as privilege in later job requests. Nevertheless D. was already thinking about moving to America. In 1835 he sold all of his assets, including all books, and was already preparing for a voyage to America, when he was offered the post of mathematics and commercial accounting professor at the Royal secondary modern school in Prague. But even in this post, which was on a par with the profession of a grammar school teacher, he was looking for opportunities in other parts of the monarchy until he got the opportunity to substitute a professor of higher mathematics and practical geometry at Prague Polytechnic. In 1836 he married Mathilda Strum, the daughter of Salzburg goldsmith. They had five children. In 1841 the period of substitution ended and D. got a regular post of elementary mathematics and practical geometry professor at the Polytechnic. He stayed the longest at this post, up to 1847. In the meantime he suffered more and more because of bad lungs, which were probably damaged already in his father's workshop, saturated with dust. Moreover, in big cities, there was always the risk of tuberculosis. D. fought with a large number of students and tests. Already during his replacement a criticism of the manner and content of his teaching and the textbooks which he used in the classroom (in 1843 he issued his own textbook, entitled "Arithmetic and Algebra") were criticized. He also invested a lot of time and effort in working at the Royal Czech Society of Science, which in 1840 elected him a corresponding and in 1843 a full member. Bernard →Bolzan was his Maecenas and sponsor. D. was also socially committed, and aware of the hard social and living conditions of much of the population of large cities.
In 1847 he grabbed the opportunity and accepted the post of professor of mathematics, physics and mechanics at the Academy of Mining and Forestry in Banská Štiavnica, where he was also nominated for a mining consultant. During his stay in Banská Štiavnica he was honoured with honorary doctorate by the University of Prague and the Imperial Academy of Sciences in Vienna elected him a full member. At the end of 1848 he received an invitation to the Department of practical geometry of the Polytechnic Institute in Vienna, but he stayed in Banská Štiavnica due to the revolutionary incidents of March 1848. When as a result of a school reform under minister Thun in 1850 the new Institute of Physics was established at the University of Vienna, D. was its first President, being also given the position of a full professor for experimental physics at the Faculty of Arts. In the winter semester of 1852/53 school year he had to ask for leave due to his ill health. He went on treatment in Venice, where he died six months later. A relatively large number of D.'s change of residence is not the result of his internal restlessness, but the need for education and subsequently the need for secure employment. D.'s geographically scattered publications reflect his life stations and the themes of publications reflect the interests of the individual periods of his scientific career. D.'s first works were published in the Vienna Polytechnic yearbook, starting in 1832 and in the Baumgartner newspaper of Physics (Vienna) from 1837 and from 1840 on (apart from a short contribution in 1837) outside Austria in Poggendorff's annals of physics and chemistry (Leipzig).
When he lived in Prague, he from 1841 on published a treatise of the Czech Society for Science and partly separate publications with the publishing house »Borrosch & André«. In 1842 he published a paper in which he formulated a principle, later named after him, titled »Ueber das farbige Licht der Doppelsterne und einiger anderer Gestirne des Himmels« (On the coloured light of the double stars and certain other stars of the heaven). From 1842 on he published in the Hessler encyclopaedia journal about technical problems that were closer to practice. When in 1848 he became a member of the Vienna Academy of Sciences, he published in its publication »Sitzungsberichte«. In these contributions he discussed topics, with which he was already engaged in Banská Štiavnica, where mineshafts, suitable for experiments and measurements were available, as well as notes that were left by previous generations of practitioners. Thus, at this time D. had to seek contact with mine offices throughout the monarchy. When in 1849 the University received the newly discovered gelatinous substance, D. was tasked to write a report about it. In his honor the Director of the Imperial Geological Survey named the substance after him. His most important achievement is the defence of the D.'s principle, discovered by him in Prague in the early 1840s, where he spent probably not his happiest, but scientifically certainly most productive period. In the dispute he had with mathematician Joseph →Petzval he was, among others, supported by Andreas von Ettingshausen, who succeeded him as director of the Institute of Physics.
D's theory established itself, although a lot of people opposed it for a long time. Today the principle, where the frequency of waves changes due to the movement of a sound or light source, is in use in many technical areas, while the processes and devices bear D's name.