Axel Gadolin

Axel Vilhelmovich Gadolin (; 12June 1828 – 15December 1892) was a Finnish/Russian lieutenant general, and also a scientist in the field of artillery, metallurgy, mineralogy and crystallography. Gadolin was a professor at the Mikhailov Artillery Academy and the Saint Petersburg Institute of Technology, doctor of mineralogy from Saint Petersburg University, and academician of the St. Petersburg Academy of Sciences. He was awarded the Lomonosov Prize in 1868 for his work on crystallographic point groups.

Career

Gadolin was born in Somero in the Grand Duchy of Finland on 12June 1828. He was the nephew of the chemist Johan Gadolin.

Gadolin combined his military career with a scientific career in mineralogy, crystallography, and artillery sciences. Gadolin received his initial education at the Finnish Cadet School. In 1847 he was a second lieutenant in the Russian artillery service. Gadolin graduated from the Mikhailov Artillery Academy in 1849 and remained their to teach; his initial appointment was as a lecturer in physics. He was appointed director of the artillery school in 1856 (and promoted to captain), and then professor in 1866. In 1859 he was promoted to colonel, and in 1866 to major general. While at the artillery school he developed techniques for building high velocity canons, which significantly increased the range that a shell could be propelled. reprinted in 1954, translated into French in 1871, and German in 1896.

In this work Gadolin used the law of rational indices to prove that only 2-, 3-, 4-, and 6-fold axes are possible in crystals. He showed that it is possible to derive all the crystallographically possible polyhedra by studying how the elements of symmetry can be combined. Gadolin showed that the resulting polyhedra can be divided into 32 classes varying by symmetry. This is the foundation of the modern classification into geometric crystal classes. Although he predicted 32 crystal classes, Gadolin found only 20 examples in nature. Gadolin work was often cited as the most important source for the systematic derivation of the crystal classes without using the concepts of group theory.

Moritz Ludwig Frankenheim in 1826 and Johann F. C. Hessel in 1830 had found the 32 crystal classes. Gadolin, who was unaware of the work of his predecessors, found them independently using stereographic projection to represent the symmetry elements of the 32 groups. Gadolin's work had a clarity that attracted widespread attention, and caused Hessel's earlier work to be neglected. Gadolin influenced the later crystallographic work of Paul Groth.

In 1883 Evgraf Fedorov completed his Elements of the theory of figures; Gadolin assisted in its eventual publication in 1885. Fedorov and Arthur Moritz Schoenflies added new symmetry elements such as glide reflection to those considered by Gadolin; using these new symmetry elements they enumerated the 230 space groups in three dimensions in 1891.

Gadolin's mineral collection is held at the Finnish Museum of Natural History.

Honours and awards