(Born: Nuremburg, Germany, 27 April 1796; Died: Marburg, Germany, 3 June 1872) German physician, crystallographer & mineralogist.

Hessel attended the industrial school in Nuremburg, before studying science and medicine at Erlangen and Würzburg. He received his M.D. in 1817. At the University of Münich, he continued his studies and came into contact with K.C. von Leonhard who convinced Hessel to become his assistant when the former took a position at the University of Heidelberg. There, Hessel developed his mineralogical skills, obtaining his Ph.D. in 1821. Then he was called to Marburg where he accepted a position as associate professor of mineralogy and mining technology. In 1825, he was appointed a full professor, a position he kept until his death. Over his career he published over 40 books and papers on a wide range of subjects, but it was not until many years after his death that the importance of the Kristallometrie [described below] was recognized.

Biographical references: ADB: 12, 307. • Burckhardt, Symmetrie der Kristalle, 1988: p. 41. • DBA: I 529, 408-417; II 576, 189-192. • DSB: 6, 358-9 [by J.G. Burke]. • Hess, E., "J.F.C. Hessel: Zur Säcularfeier seines Geburtstag", Neues Jahrbuch für Mineralogie, 2, (1896), 107-22. • NDB: 9, 23 [by H. Seifert]. • Poggendorff: 1, col. 1097, 3, 626 & 4, 636. • Schürmann, K., 200 Jahre Hessisches Mineralien-Kabinet 1790-1990. Festschrift. Marburg, 1990: 14-6. • Sohncke, L., "Die Entdeckung des Eintheilungsprincips der Krystalle durch J.F.C. Hessel", Zeitschrift für Krystallographie, 18, (1891), 486-98. • WBI.

Kristallometrie, 1831

1. German, 1831 [First separate edition].
Kristallometrie, | oder | Krystallonomie und Krystallographie, | auf eigenthümliche Weise | und | mit Zugrundlegung neuer allgemeiner Lehren | der reinen Gestaltenkunde, | so wie mit vollständiger Berücksichtigung | der wichtigsten Arbeiten und Methoden | anderer Krystallographen, | bearbeitet von | Joh. Friedr. Christian Hessel, | Dr. d. Med. und Phil. und Prof. der Mineralogie zu Marburg. | Nebst einem Anhange | über Krystallogenie | von | L. Gmelin, | Dr. d. Med. Geh. Hofr. und Prof. d. Chemie zu Heidelberg. | Besonders abgedruckt aus Gehler's phys. Wörterbuche. | Mit 11 Kupfertafeln. | [ornate rule] | Leipzig, 1831. | Bei E.B. Schwickert.

8°: π⁹ 1-21⁸ 22⁵; 182l.; [i]-xviii, [1]-346 p., folding plates XIX-XXIX showing crystal drawings all signed Anton Karcher sc. Page size: 212 x 124 mm.

Contents: [i-ii], Title page, verso blank.; [iii]-xiv, "Vorrede."-signed J.F.C. Hessel, July 1830.; [xv]-xviii, "Inhalt."; [1]-318, Text of Hessel's work.; 318-338, "Ueber | Kristallbildung | von L. Gmelin."; [339]-346, "Verzeichniss | der wichtigeren Verbesserungen, welche vor dem | durch lesen zu bewerkstelligen sind."; [At end], Plates XIX-XXIX.

Very rare. This is the first separate publication of Hessel's proof of the existence of only thirty-two symmetry crystal classes, by establishing the fact that only two-, three-, four- and sixfold axes can occur. Hessel obtained his results from an exhaustive physical analysis of the possible types of symmetry that any geometrical form might possess. It was first published as an article titled "Krystall" in Gehler's physikalisches Wörterbuch (Leipzig, 1830). Its importance was immediately recognized by Gehler [see note below], who arranged its publication as a separate work, and added an appendix on the formation of crystals. Unfortunately, this attention did not gain Hessel's theorem the recognition of his contemporaries, and the discovery of this fundamental principle of crystal symmetry is generally attributed to the elegant mathematical derivation published by Auguste Bravais in the mid-1850's, even though the forgotten work of Moritz Ludwig Frankeheim predates both Hessel and Bravais.^[1] This is Hessel's most important scientific work and priority over Bravais was overlooked until Leonhard Sohncke drew attention to its importance in 1891.^[2]

Notes: [1] M.L. Frankenheim, "Crystallonomische Aufsätze," Isis (Jena), 19 (1826), 497-515 & 542-65 [Rediscovered by J.J. Burckhardt, Die Symmetrie der Kristalle, Basel, 1988].

[2] L. Sohncke, "Die Entdeckung des Eintheilungsprincips der Krystalle durch J.F.C. Hessel," Zeitschrift für Krystallographie, 18 (1891), 486-98.

L. Gehler. (Born:      ; Died:      ) . Need Biography.

Bibliographical references: Burckhardt, Symmetrie der Kristalle, 1988: 31 ff.. • Dana's 7th (Bibliography): 73. • GV (1700-1910): 60, 485. • Hess, E., "J.F.C. Hessel: Zur Säcularfeier seines Geburtstag", Neues Jahrbuch für Mineralogie, 2, (1896), 107-22. • Sohncke, L., "Die Entdeckung des Eintheilungsprincips der Krystalle durch J.F.C. Hessel", Zeitschrift für Krystallographie, 18, (1891), 486-98. (Gehler)

2. German, 1897 [Reprint].
Kristallometrie, | oder | Krystallonomie und Krystallographie, | auf eigenthümliche Weise und | mit Zugrundlegung neuer allgemeiner Lehren | der reinen Gestaltenkunde, | so wie mit vollständiger Berücksichtigung | der wichtigsten Arbeiten und Methoden | anderer Krystallographen, | bearbeitet von | Joh. Friedr. Christian Hessel, | Dr. d. Med. und Phil. und Prof. der Mineralogie zu Marburg. | (1830.) | [rule] | Besonders abgedruckt aus Gehler's phys. Wörterbuche. | Erstes Bändchen. | Mit 8 Tafeln. | Herausgegeben | von | E. Hess. | [ornate rule] | Leipzig | Verlag Von Wilhelm Engelmann | 1897.

2 vols. [Vol 1] 8°: [Vol 2] 8°:

Scarce. Edited by E. Hess [??-??]. In 1891, Leonhard Sohncke rediscovered the importance of Hessel's Kristallometrie; however, the original 1831 publication [described above] was so difficult to obtain that Ostwald reprinted this abridged version of the text for a wider audience.

Bibliographical references: Dana's 7th (Bibliography): 73.

3. German, 1847.
Löthrohrtabellen für mineralogische und chemische Zwecke. Marburg, Elwert, 1847.

8°: 24 p.

Very scarce. Blowpipes.

4. German, 1862.
Ueber gewisse merkwürdige statische und mechanische Eigenschaften der Raumgebilde ... Marburg, 1862.

8°: Very scarce.

Bibliographical references: Burckhardt, Symmetrie der Kristalle, 1988: 40 ff [reproduces the title page].

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