494 



NATURE 



[Majr/i. 25, 1886 



the value of his scientific work, all designated him for 

 some superior professorship ; so, in 1852, he was elected 

 Professor of Physics at the Polytechnic School. He lec- 

 tured there with success for twenty-nine years — till 1 88;, 

 when he resigned. 



In 1S63 he was appointed Professor at the Sorbonne, 

 where, till his death, he attracted a great number of 

 eager listeners. In this position he displayed his admir- 

 able talent of exposition, his great power of simplifying 

 the most difficult questions, and of indicating by most 

 striking apparatus the methods of solving many intricate 

 problems. 



The qualifications that Jamin displayed in his oral 

 teaching are found in the " Trait(5 General de Physique," 

 which reproduces his course at the Polytechnic School, 

 and in which masters as well as pupils find e.xact descrip- 

 tions of the actual state of science. 



Jamin was not only a physicist ; his mind was open to 

 all manifestations of intelligence. At the Normal School, 

 in preparing for his degree in physics, he found time to 

 obtain one in natural sciences also. At Caen he went 

 with his pupils on Sundays on botanical and geological 

 excursions. But it was only on his return to Paris that 

 his great power, elevated ideas, distinguished tastes 

 and his fine intelligence could find a free scope. He re- 

 membered always with pleasure how at the age of twenty- 

 five he found himself at once surrounded by an intelligent 

 and enlightened society. He dined in a pension with 

 several of his colleagues, who have left names either in 

 science or at the University : with Lefebvre, the eminent 

 professor at the College Rollin, with Saisset, Barni, 

 Suchet, La Provostaye ; with Faurie, who often brought 

 his friend Sturm. The dinner was followed by long chats, 

 dissertations on science, philosophy, music and art, 

 in which Jamin took an active part. He loved music ; he 

 was a painter. He was an early riser, and on Sundays he 

 went with one or two of his colleagues to study the works 

 of the great masters at the Louvre. He painted an ad- 

 mirable portrait of Lefebvre ; his family preserve several 

 of his paintings, and the church at Termes possesses a 

 picture of his composition. 



But art and literature only occupied his leisure ; he 

 produced at that period his most important scientific 

 works — works which procured for him in 1868 admission 

 into the Academy of Sciences. 



His researches embrace the most varied subjects. 

 Besides his optical, magnetic, and electrical researches, 

 which remain his best titles to fame, his studies on 

 the compressibility of liquids, on capillarity, hygrometry, 

 specific heats, the critical points of gases, prove the 

 originality and versatility of his genius. 



By their historical order and succession his memoirs 

 indicate the progress of physics in France since the 

 middle of the century to the present day. A pupil and 

 admirer of Cauchy, it was by his optical experiments that 

 he made his debut, and it was also to this subject that he 

 most frequently returned. 



He took great pains to invent methods of measurement 

 delicate enough to control the analytical results of Cauchy, 

 and his first memoir is a beautiful study of reflection of 

 light by the surfaces of metals. He discovered after- 

 wards the elliptical polarisation of light reflected by 

 vitreous substances near the polarising angle, anticipated 

 by Cauchy's theory ; and discovered at the same time the 

 negative elliptical polarisation of fluorine, which no one 

 suspected. He published a long memoir on coloured 

 rings, and invented interference-apparatus utilising the 

 light reflected on opposed faces of thick transparent 

 plates. 



When in 1868 M. Durny, then Minister of Public 

 Instruction, founded the Ecole Practique des Hautes 

 Etudes, and endowed a research laboratory, Jamin 

 profited by the powerful aid thus placed at his disposal. 

 The rapid and so unlooked for progress in electricity 



supplied a new field for his activity. Assisted at first by 

 inexperienced workers, he thought, and worked for all ; 

 he undertook ten difterent researches, of which one would 

 have absorbed all the time and power of one less in- 

 defatigable. 



Cruelly touched by family affliction, he found in the 

 midst of his workers, who needed continually his aid and 

 assistance, some relief for his great grief. During some 

 time before his death he seemed to have mastered his 

 sorrows and to have regained his usual activity. He had 

 succeeded his illustrious master, M. Dumas, as Perpetual 

 Secretary of the Academy of Sciences, and no one was more 

 fitted to have filled this delicate office. He had replaced 

 Milne Edwards as Dean of the Faculty of Sciences, and 

 at the time of his death he was at the height of his 

 reputation. 



His death leaves a large gap in Parisian scientific society, 

 and those English men of science who had the privilege 

 of knowing him and admiring his genial and powerful 

 nature and his admirable private life w-ill long mourn his 

 loss. R. 



THE U.S. NAVAL OBSERVATORY^ 



IN 1880 a site was purchased for a new Naval Observa- 

 tory a short distance beyond Georgetown, in the 

 district of Columbia ; but no appropriation has yet been 

 made for erecting the necessary buildings and removing 

 the instruments from the present location. On account 

 of this delay the Secretary of the Navy, in April 1SS5, 

 called upon the National Academy of Sciences for an 

 expression of opinion as to the advisability of proceeding 

 promptly with the erection of a new Naval Observatory ; 

 and the reply of the Committee of the Academy is con- 

 tained at length in a letter from the Secretary of the 

 Navy, just published as Executive Document No. 67. 

 The conclusions of the Committee we give in the lan- 

 guage of the Report. This Report is signed by F. A. P. 

 Barnard, A. Graham Bell, J. D. Dana, S. P. Langley, 

 Theodore Lyman, E. C. Pickering, C. A. Young. (l) It 

 is advisable to proceed promptly with the erection of a 

 new Observatory upon the site purchased in 1S80 for this 

 purpose. (2) It is advisable that the Observatory so 

 erected shall be, and shall be styled, as the present Ob- 

 servatory was styled originally, the " National Observa- 

 tory of the United States," and that it shallbe under 

 civilian administration. (3) It is advisable that the 

 instruments in the present Observatory, with the ex- 

 ception of the 26-inch telescope, the transit circles, 

 and the prime vertical transit, shall be transferred 

 to the Observatory at Annapolis, with such members 

 of the astronomical staff as may be required to operate 

 them ; also that such books of the library as relate chiefly 

 to navigation shall take the same destination ; the instru- 

 ments above particularly specified, with the remainder of 

 the library, being reserved as part of the equipment of 

 the new National Observatory, to which also the remaining 

 officers of the astronomical staff shall be assigned for 

 duty. (4) It is advisable that the Observatory at Anna- 

 polis shall be enlarged, if necessary, and adapted to 

 subserve as effectually as possible the wants of the Naval 

 Service, whether practical, scientific, or educational ; that 

 it shall be under the direction of the department of the 

 Navy, and shall be styled the " Naval Observatory of the 

 United States." The grounds upon which this decision 

 is based are set forth in the document to which we have 

 referred ; and numerous letters are appended, from astro- 

 nomers and others, in regard to the administration of the 

 Observatory, and from physicians of Washington, upon 

 the healthfulness of the portion of the city in which the 

 Observatory is at present situated. It will be seen imme- 

 diately that this report is intended to favour the establish- 

 ment of an Observatory worthy of the country, and the 

 * From Science. 



