Klingenstierna, Samuel

(b. near Linköping, Sweden, 18 August 1698; d. Stockholm, Sweden, 26 October 1765)

physics.

Klingenstierna was the son of a Swedish army officer and the grandson of two bishops. After having studied at the University of Uppsala and pursuing various activities, including service as a secretary to the Swedish treasury, in 1727 he began a study tour of great importance for his scientific development that led him to Marburg, Basel, Paris, and London. After his return in 1731 Klingenstierna was professor of geometry at the University of Uppsala, a position to which he had been appointed in 1728. He contributed decisively to the development of teaching and research in mathematics and physics at Uppsala, and in 1750 he took over the newly created chair of physics. In 1754 Klingenstierna was appointed teacher to the Swedish crown prince (later Gustavus III) and became a highly respected member of the Swedish court. He held this difficult position, one rather inappropriate fro a man of his qualifications, until 1764, the year before his death.

Klingenstierna was an able mathematician and physicist. In the history of physics he is remembered mainly for his important contributions to geometrical optics, having been the first to give a comprehensive theory for achromatic and aplanatic optical systems (systems without color dispersion and spherical aberration).

According to Newton, achromatic refraction is impossible: the dispersion is proportional to the refraction. This was denied by Euler, who cited the human eye as a seemingly achromatic lens system and asked the famous optical instrument maker John Dollond to conduct new experiments in this field; but Euler’s proposals did not lead to successful results.

At this stage Klingenstierna, in a paper published in Kungliga Svenska vetenskapsakademiens Handlingar in 1754, gave a complete theoretical proof that Newton’s assertion disagrees with the fundamental law of refraction. Through Mallet he informed Dollond of this proof, and Dollond immediately began to investigate the problem experimentally. He first found that an experiment mentioned by Newton in his Opticks could not be correct: A glass prism was placed in a prism filled with water so that the light was refracted in opposite directions by the two prisms; for a suitable angle of the water prism it was then found that there was no refraction but that the color dispersion did not vanish, as postulated by Newton. Dollond further showed that by increasing the angle of the water prism it was possible to obtain refraction without dispersion, because the dispersion of glass is greater than that of water. Although these findings were in complete agreement with the results presented in Klingenstierna’s paper, he was not mentioned in Dollond’s account of his own investigations, published in 1758 in Philosophical Transactions of the Royal Society.

In this paper Dollond also described his successful construction of achromatic lenses, first by using water and glass, and later crown glass and flint glass, as refractive media. He also showed how he succeeded in the approximate elimination of the spherical aberration.

After reading Dollond’s paper Klingenstierna took up the problem of achromatic and aplanatic lens systems for theoretical investigation. In 1760 he published in Kungliga Svenska vetenskapsakademiens Handlingar a comprehensive theory for such lens systems, referring to Dollond’s experimental results and mentioning that he had made Dollond aware of his proof that Newton’s assertion was wrong. Klingenstierna’s important 1760 paper is now considered a classic contribution to geometrical optics, paving the way for the later works of Abbe and Gullstrand.

Dollond continued to deny the importance of Klingenstierna’s contributions for his own research, and consequently Klingenstierna in a letter to the secretary of the Royal Society protested against this attitude. He also challenged Dollond to enter a competition, arranged by the St. Petersburg Academy of Sciences, concerning the removal of the imperfections in optical instruments caused by color dispersion and spherical aberration. Dollond did not accept the challenge, and Klingenstierna was awarded the prize. His paper, mainly of the same content as that of 1760, was published in 1762 in the Proceedings of the St. Petersburg Academy.

BIBLIOGRAPHY

I. Original Works. Klingenstierna’s proof that achromatism is not impossible is given in “Anmärkning vid Brytnings-Lagen af särskilta slags Ljus-strålar, da de gå ur ett genomskinande medel in i åtskilliga andra”, in Kungliga vetenskapsakademiens Handlingar (1754), pp. 297–300. His general theory of achromatic and aplanatic lens systems is “Om ljusstrålars aberration efter deras brytning genom Spheriske Superficier och Lentes”, ibid., 21 (1760), 79–125. His treatise for the St. Petersburg Academy competition is “Tentamen de definiendis et corrigendis aberrationibus radiorum lumines in lentibus sphaericis refracta et de perficiendo telescopio Dioptrico” (1762).

II. Secondary Literature. Works on Klingenstierna include G. Gezelli, Biographiska lexicon, II (Stockholm, 1779), 38–41; Harald J. Heymann, “Samuel Klingenstierna”, in Sten Lindroth, ed., Swedish Men of Science (Stockholm, 1952), pp. 59–65; H. Hildebrand Hildebrandsson, Samuel Klingenstiernas levnad och verk, I, Levnadsteckning (Stockholm, 1919), which includes an account of the controversy between Klingenstierna and Dollond; C. G. Nordin, Minnen öfver namnkundiga svenska mäm, I (Stockholm, 1818), 232–254; and Mårten Strömer, “Åminnelsetal över S. Klingenstierna”, in Kungliga VetensKapsaKademiens Åminnelsetal, III (1763-1768).

Mogens Pihl