xlvi 



by excessive mental exertion. He obtained leave of absence from the 

 Observatory in the spring of 1863, and resigned bis post as Director early 

 in 1864. He passed the remainder of his life in the midst of his family 

 at Spandau. His judgment and memory remained unimpaired till within 

 a few weeks of his end. He died on the 26th of August, 1865. 



Adolf Theodor von Kupffer, For. Memb. R.S., was born at Mitau, 

 in Courland, where his father was a merchant, on the 6th of January (Old 

 Style), 1799. At the age of sixteen lie entered the University of Dorpat as 

 a medical student, but remained there only a few months. In 1816 he 

 entered the University of Berlin, also as a medical student, but the study 

 of medicine becoming distasteful to him, he applied himself to the ma- 

 thematical and physical sciences, and to mineralogy, under the direction 

 of Weiss. In 181 9 he went to the University of Gottingen, and in 1820 to 

 Paris, where he attended Haiiy's lectures on Mineralogy. He established 

 himself in St. Petersburg, where he lectured on mineralogy in the winter of 

 1821-1822. In the spring of 1822 he was appointed Professor of Physics, 

 Chemistry and Mineralogy in the University of Kasan, and at the same 

 time commissioned to visit Paris for the purpose of procuring a collection 

 of physical instruments. While there he competed successfully for a prize 

 proposed by the Academy of Berlin for an essay on the measurement of the 

 angles of crystals. In concert with Arago he planned a series of observa- 

 tions on the daily variation of the magnetic declination, and the disturb- 

 ances of the declination, at Kasan. He entered upon the duties of his 

 Professorship in June 1823, devoting the time not occupied in teaching to 

 crystallography and magnetism. In April 1828 he was sent on a scientific 

 mission to the Ural, the results of which were published in 1834. They 

 consist mainly of geological observations, the discovery of new localities of 

 some scarce minerals, and of many determinations of the temperature of the 

 soil, made conjointly with Adolf Erman. 



Having been elected a member of the Imperial Academy of Sciences, he 

 went to reside in St. Petersburg in August 1828. Early in 1829 he suggested 

 to the Academy the erection of a small magnetic observatory. The project 

 was warmly supported by von Humboldt, who happened to be in St. Pe- 

 tersburg on his way to the Ural and Altai. It was approved of by the 

 Academy, and the building commenced before the end of the year. In the 

 summer of 1829 he was placed at the head of a scientific party engaged 

 in exploring a part of the Caucasus near Mount Elbrus, into which no 

 European had ever penetrated before, and where, for the pl'otection of the 

 travellers against the native tribes, they were accompanied by a strong 

 escort of troops under the command of General Immanuel, the General in 

 command of the Caucasus, who had planned the expedition. 



At this period he lectured at the School of Civil Engineering, the Piida- 

 gogische Institut, and the Academy for Naval Officers, and was engaged 

 in writing his ' Handbuch der rechnenden Krystallometrie,' which appeared 



