Fraunhofer, Joseph von (1787 - 1826)

Joseph Fraunhofer was born on the 6. March 1787 in Straubing as the eleventh and last child of Franz Xaver Fraunhofer, a glazier. Seven of his brothers and sisters died early, his mother, aged 54, when Joseph was 10. One year later his father died, aged 56. Joseph was not sent to school regularly but had to help his father in the workshop. They were different times then, everyone had to help in the family; there was just no time and money to send the children to school. The Bavarian state had improved much on the educational system, but only in 1802 public schools with compulsory participation were introduced.

Franz Xaver Fraunhofer, Joseph’s father, was neither poor nor rich, when he died. He owned a house, located very conveniently in the center of the town. This 5 storey building, slightly changed over the years, is still existing.

Joseph started an apprenticeship with a wood turner, but changed to a glazier soon since he was not strong enough for the hard work. He began his work on the 23. August 1799 in the workshop of Weichselberger in Munich. There, in the capital of Bavaria, which was 50 times bigger than Joseph’s home town, life was even harder. A sister, already living in Munich, cared for his clothes.

Weichselberger was a strict master. Beside teaching him the business of a glazier he ordered Joseph to do every day’s housework, but that was usual those days. But worse was that Weichselberger forbade him to visit Sunday school and reading. Joseph Fraunhofer was eager to learn and tried to get books wherever he was.

The collapse of two houses on the 21. July 1801 changed Fraunhofer’s life forever. One of these houses was rented by Weichselberger: in the ruins died the master’s wife, but Joseph was found almost unhurt when he was rescued after 4 hours. On the scene of the disaster were two persons who would change the future of his life: Maximilian Joseph, later to be King Max I., and Joseph Utzschneider, a politician and entrepreneur. Just some weeks before this event Utzschneider had left his political posts to concentrate on his business: making fine instruments and optics.

It was through this event that Fraunhofer became known not only in the neighborhood, but also at other places. His master Weichselberger could no longer forbade him the visit to Sunday school, he went there for four years. Maximilian Joseph presented him some money and assured him of his fatherly protection. Fraunhofer kept the extra money for a while and later bought a glass cutting machine and a grinding machine with it. Utzschneider seems to have supported Fraunhofer with books and talks about optics and physics. The probability of earning better money with making spectacle lenses was well known to Fraunhofer.

Joseph Fraunhofer left the workshop of Weichselberger, who had moved to a different place in Munich (Kaufinger-Gasse), on the 30. April 1804. The certificate of apprenticeship gives October 1804 as the last month of Fraunhofer working there, but Fraunhofer redeemed himself from the 6 years contract. He went to work with Joseph Niggl, who had learned how to grind lenses in the convent at Rott. To earn some money Fraunhofer started to draw, engrave and print business cards. Unfortunately he did not earn enough to keep on with his studies, he returned to his former master Weichselberger as journeyman.

Utzschneider, who had met Fraunhofer first in the damaged house, sent him to meet a Benedictine monk named Ulrich Schiegg. This monk examined Fraunhofer for some days and recommended him to Utzschneider and Reichenbach. Fraunhofer left the glaziers workshop finally on 19. May 1806.

Georg Reichenbach and Joseph Utzschneider had founded a workshop in Munich in 1802 to produce geodetic instruments; good maps were rare these days and the State as well as the Army needed them. Reichenbach studied at the military academy in Mannheim, was sent to England to learn about James Watt’s steam engines, and returned to Mannheim in 1793. During his time in England he also learned about optical instruments from Ramsden, Dollond and others. Around 1800, while being with the Bavarian army in a camp at Cham, he thought about and developed a dividing machine to engrave circles with the highest precision. Later the astronomer Bessel found an average error of only 0.325 arc seconds on the instruments made by Reichenbach.

Reichenbach had some instruments on his shelves, almost ready to be sold. The only thing missing were the optics. It was Fraunhofer’s first task to grind and polish these when he joined the workshop. His assets were his craftsmanship, some books, probably some English telescopes and instruments made by Georg Friedrich Brandner (1713-1783) in Augsburg. The instruments with the first Fraunhofer optics went to the observatory at Ofen, near Budapest in Hungaria. Fraunhofer started to analyze every step in the making of a lens and introduced new techniques in grinding them. He developed a polishing machine that made the process more independent from the workers craftsmanship. Another area of work was the composition of the polishing material and the cement that was used to put the lenses together. And Fraunhofer introduced an absolutely plane sheet of glass as a test device to check for the shape and concentricity of the polished lens surface. With these new materials and methods Fraunhofer reached a much better surface quality within the first years.

The next change came at the end of 1807 when Utzschneider moved the whole business to Benediktbeuern where he had founded a glass melting workshop. This small glass factory should supply the raw material for the optics, glass of a higher quality than could be purchased on the market. During his calculations and tests for perfect optics Fraunhofer had found the glass to be a major variable in the process. It was there that Fraunhofer met the Swiss Pierre Louis Guinand.

Utzschneider had met Guinand in Neuchatel, Switzerland, during his travels, searching for sources of streak-free glass. In 1806 they agreed on a contract that brought Guinand to Benediktbeuern for 500 Guilders a year. His task was to make high quality crown and flint glass and he introduced a stirrer to the process. The quality of the glass was acceptable for lenses, but it still varied from batch to batch.

In 1809 Utzschneider ordered Guinand to introduce Fraunhofer to the secrets of glass melting. He used the same scientific means as in figuring his lenses and changed the volume of the melting pots, searched for better raw materials like quartz, lime and potassium carbonate. He even developed new glass sorts, suited to make bigger and better optics. From 1809 on Fraunhofer had responsibilities like an entrepreneur: he was made a companion of the firm and got one third of the profit, less 400 Guilders for company expenses, plus a 480 Guilders salary. In the same year Fraunhofer presented a production plan that required one instrument per day leaving the factory. Beside the small telescopes the company made microscopes, opera glasses, loupes and finally the big astronomical telescopes and heliometer.

Guinand left Benediktbeuern in 1814 and went back to Switzerland. It was Fraunhofer who had now the full responsibility for glass melting and calculating the lenses. It was the same year when Reichenbach left the firm and Utzschneider made Fraunhofer his partner. His salary had grown to 1500 Guilders, free lodging and heating in winter. A list describing 37 instruments and including prices offers a heliometer at 1430 Guilders, some ‘comet seekers’, astronomical telescopes, terrestial telescopes, loupes and prisms. A microscope with six objectives and two eyepieces is listed at 520 Guilders, smaller microscopes and a traveling microscope are mentioned. The biggest instruments are the astronomical refractors, starting at 18 centimeter (6.5 inch) diameter. The price is given as „... to be negotiated.“ These telescopes required a lot of know-how and engineering, like streak-free glass and a springloaded lens mounting that kept the objective parts axially and radially in the designed position.

The ‘depth’ of the production was immense. Almost everything was made by the Utzschneider and Fraunhofer company. Brass and forgings were purchased, all other parts were made by employees in the workshop or at their homes. Nuts and bolts, clockworks, tripods, precision shafts, everything was made. The wooden tubes for the telescope were made by the carpenter Riesch. He used a big drill to make the holes in wooden shafts and glued the bigger tubes together from many thin sheets. Fraunhofer calculated, designed and tested every instrument, wrote the manuals and watched the disassembling and packaging process for the bigger telescopes.

In 1817 Utzschneider faced financial troubles. He had invested a lot of money in a weaving mill that could not sell enough of the fabrics to get his investments back. The additional break down of a bank forced Utzschneider to sell the former convent buildings in Benediktbeuern back to the state. The glass works, the carpenter and some minor workshops stayed there, the main part was transferred to Munich. This relocation delayed the completion of a major telescope: the big refractor for the Russian observatory in Dorpat (now Tartu in Estonia).

The objective lens for this telescope was finished in 1819, the complete instrument was shipped in 22 crates in 1824 and arrived in Tartu on the 10. November that year. Based on Fraunhofer’s description of the instrument, its individual parts, the probable errors that could be made during assembly and the handling of the complete instrument it was erected without any problems. Fraunhofer stayed in Munich. The complete instrument saw ‘First Light’ in the early hours of the 16. November. It was first located in a room that allowed a view of about 10 degrees on both sides of the meridian, it was moved to a domed tower 6 months later. With the telescope came four eyepieces for magnifications between 175 and 700 times, plus four micrometers of different kinds. Within the following three years the astronomer Struve observed and measured the distances of over 3000 double stars.

It was around 1813 when the glass works and the optics workshop still did fine, that Fraunhofer researched the different sorts of glass. He re-discovered the dark lines in the spectra. These lines had been seen before by Wollaston, but he did not pay them the same interest as Fraunhofer. 574 lines were described by him, to the stronger he assigned the letters A to Z, which are still used today. The drawing of the spectrum, which still exists, and the printing plate engraved by himself are masterpieces in their own right.

After this basic work he used his instruments on the light of electric sparks, different light sources and stars. Fraunhofer wrote down his findings and presented them to the bavarian Academy of Sciences on the 12. April 1817, which published it in the same year. Other works on the theory of light were published in the following years.

The ‘Civil Order of the Bavarian Crown’ elected Joseph Fraunhofer as a member and he was knighted on 15. August 1824. During the years in Munich Fraunhofer teached at the University of Bavaria. One of his pupils was Friedrich August Pauli, who also worked at the glassworks for six months. Fraunhofer offered his company to the Bavarian King in a letter dated 24. April 1826, mentioning Pauli as his only possible successor as a leader of the company.

Joseph von Fraunhofer died on the 7. June 1826 and was buried three days later at the Südfriedhof (southern cemetery) in Munich next to Reichenbach. The Munich firm kept on building telescopes and other instruments according to Fraunhofers plans, Utzschneider himself attended the glass melting pots until 1832.

In 1839 he sold the firm to Merz, who had already hired Mahler. They now renamed the company „G. Merz & Mahler“. Georg Merz died on the 12. January 1867 and left the business to his sons, Sigmund and Ludwig Merz. Sigmund Merz turned over the business to his nephews Jakob and Matthias Merz in 1883.

The refractor in Tartu was restored in 1993 (link)

This page created by Chris Plicht