40 



NATURE^ 



\_Nov. 14, 1878 



derive nitrogen from the air," but, on the contrary, has 

 pointed out that all the nitrogen assimilated by them 

 may be accounted for in the different compounds of that 

 body which are supplied to the plant in other ways. 

 Boussingault' s experiments also on the nutritive proper- 

 ties of the nourishment supplied to herbivorous animals 

 are of great interest. In these he has traced the distri- 

 bution of the various constituents of the food by the 

 vital process, and has determined the different quantities 

 of the various constituents which undergo assimilation. 

 Besides investigations in the directions just indicated, 

 he has introduced various improvements in methods of 

 analysis, and has published many valuable articles, most 

 of which are collected in his " M^moires de Chimie Agri- 

 cole et de Physiologie ; " he has also written a work 

 entitled " Traitd d' Economie Rural." 



With the work of Mr. J. Allan Broun most of our 

 readers must be familiar. On the commencement of 

 magnetic observations he indicated the errors or insufifi- 

 •ciencies of the methods for determining coefficients and 

 correcting the observations issued by the committee of 

 the Royal Society for the instruction and direction of 

 superintendents of observatories ; he devised new methods 

 for these ends which have made the observations in all 

 the magnetic observatories available for strict scientific 

 conclusions. He has made investigations in magnetism 

 and meteorology during thirty-five years ; among the new 

 results obtained many of them are of the highest value, 

 and have taken their place as standard scientific data. 

 He established an observatory twice on a mountain- 

 peak 6,000 feet above the sea, with the complement of 

 instruments employed in first-class observatories (on the 

 •second occasion with a double series of magnetical in- 

 struments) — this, in a wild country, done amidst great 

 difficulties in erecting instruments and obtaining trained 

 observers, requiring continued and persevering action. 

 This and many other duties were done at his own expense, 

 and though, in general, ultimately repaid, they yet in- 

 cluded considerable pecuniary loss. He also spent his 

 own means in obtaining new instruments, and in every 

 matter likely to forward science. He has laboured for 

 years without remuneration in scientific work of a 

 peculiarly tedious kind. 



Albert C. L. G. Giinther is the Keeper of the Zoo- 

 logical Department of the British Museum, a position 

 to which he succeeded on the death of Dr. J. E. 

 Gray. Very early in his life he devoted himself to 

 the study of the natural sciences, and, if we are not 

 mistaken, his earliest essay as an author was a very 

 complete memoir of the fishes of the Neckar. About 

 1854 he accepted an appointment in the British Museum 

 under Dr. J. E. Gray, who soon learned to value and 

 appreciate the services of his assistant. Dr. Giinther 

 commenced the investigation and arrangement of the 

 batrachian reptiles in the National Collection, with a 

 zeal and energy that knew no limits, and which soon 

 rendered this portion of the Zoological Department with- 

 out a rival among the Museums of Europe. Not wearied 

 by such a task he set about a far greater one, the arrange- 

 ment and description of the immense class of the fishes, 

 and no zoologist has ever raised a greater or more 

 enduring monument to his memory than Dr. Giinther has 

 done in his great and truly scientific catalogue of all the 

 known fish. The care of a large and daily-increasing 

 collection, with all the worry incident on the want of 

 room to properly store it — the toil and labour involved 

 in the publication of the extensive work just alluded to, 

 might well have excused Dr. Giinther from attempting 

 other work, but still we find him apparently never weary, 

 and memoirs of a value like those on Hatteria, on 

 Ceratodus, and on the Giant Tortoises, not to mention a 

 long list of others, were being constantly published by 

 kim. He is also the author of an important work pub- 

 lished at the expense of the Ray Society, " On the 



Reptiles of British India," and joint author with Col. 

 Playfair of a work on the "Fishes of Zanzibar." All will 

 agree that his name is a very worthy one to be added to 

 the grand roll call of the Royal Society's medallists. 



The name of M. Alfred Cornu must be familiar to the 

 readers of Nature in connection with his remarkably 

 ingenious and successful method of determining the 

 velocity of light. A detailed account of M. Cornu's 

 method will be found in vol. xi. p. 274, and succeeding 

 volumes of Nature. It was also expounded by him, it 

 may be remembered, at the Royal Institution, on May 7, 

 1875. The important bearings of M. Cornu's experi- 

 ments in various directions, we need not point out ; its 

 value in attaining an accurate estimate of the sun's 

 parallax is evident. As is evidenced by the Comptes 

 Rendus, M. Cornu's work in his own department is 

 constant and varied ; his research into' the spectrum of 

 the star that appeared in Cygnus two years ago was a 

 fine example of the result of spectroscopic research ; an 

 account of it will be found in Nature, vol. xv. Although 

 probably the youngest of the new medallists, M. Cornu's 

 long and incessant work makes him almost a veteran in 

 scientific research. 



MM. L. Cailletet and Raoul Pictet have lately been so 

 closely engaged in the same kind of experimental work, 

 namely, the liquefaction of gaseous bodies, that their 

 names have naturally become associated in connection 

 with the important results which have followed their inde- 

 pendent researches. The methods, however, employed 

 by the two chemists in obtaining those results which have 

 lately added so much to their reputation are to a certain 

 extent different. Cailletet' s experiments, which were 

 conducted on the gases air, hydrogen, marsh gas, nitric 

 oxide, and carbonic oxide, depend for the cold necessary 

 to produce the liquefaction of the gas, on the expansion 

 of the gas when suddenly compressed only at moderate 

 degrees of cold. 



Pictet's experiments, on the other hand, are the result 

 of his endeavours to discover improved methods for pro- 

 ducing and maintaining for a considerable time very low 

 degrees of temperature. Combining these improvements 

 with the production of the bodies to be liquefied under 

 great pressure, he has succeeded in liquefying oxygen 

 and hydrogen and in solidifying the latter. He has 

 also determined the specific gravities of the gases when 

 in that condition, assigning to them the weights '9883 

 and '9787. Besides his most recent researches on the 

 condensation of gases, M. Pictet has carried out other 

 investigations on those phenomena, the consideration of 

 which lies between the provinces of physics and chemistry. 

 Among such investigations may be mentioned his ob- 

 servations on the application of the mechanical theory of 

 heat to the study of volatile liquids and to some simple 

 relations between the latent heats, atomic weights, and 

 tensions of vapours. M. Pictet has also been successful 

 in applying his scientific investigations to practical use, in 

 the perfecting of apparatus for the rapid production of 

 large quantities of ice. 



We are glad to know that the health of M. Pictet is 

 not so seriously impaired by overwork as was rumoured 

 a few days ago. On the best authority it is stated 

 that his recovery is by no means beyond hope, and that 

 he is not suffering from incipient softening of the brain. 

 There is no contradiction, however, to the sad statement 

 that the sight of one of M. Pictet's eyes is gone, and that 

 he will probably lose the power of the other. 



AFGHANISTAN 



WHATEVER opinions our readers may hold as to 

 the present action of the Government with respect 

 to Afghanistan, it may not be considered inappropriate to 

 summarise briefly what we know about a country, which 

 at no remote date may become a part of the British 



