254 



NA rURE 



[January i6, 1902 



In 1S96, Moissan and Dewar, working in collaboration, 

 effected the liquefaction of fluorine bypassing it through 

 a tube cooled in liquid air which was allowed to boil 

 freely. The 15. P. of liquid fluorine is about - 187'. The 

 liquid does not solidify even at -210^ Its density is 

 i'I4 ; it e.xhibits no absorption spectrum, and is not 

 magnetic. It is soluble in all proportions in liquid air 

 and oxygen. Liquid fluorine has no chemical action on 

 liquid oxygen, solid mercury, or ice ; but even at - 210 

 it combines with hydrogen, and decomposes benzene with 

 violence, and production of light and heat. It would be 

 interesting to know the order in which the elements cease 

 to react with fluorine as the temperature falls. 



We must also refer to the hexafluoride of sulphur 

 prepared by Moissan and Lebeau in April of 1900. 

 It is obtained by the action of excess of fluorine on 

 sulphur ; it is one of the heaviest gases known, having a 

 density of 5 '03. Its composition, which is represented by 

 the formula SF,,, completely establishes the hexatomic 

 nature of the sulphur atom. It is of interest also on 

 account of its inertness ; it is unattacked by fused sodium 

 or potassium. Resulting as it does from the union of 

 two such active elements as sulphur and fluorine, which 

 in combining seem thus to saturate one another com- 

 pletely, this compound may be regarded as additional 

 evidence in favour of the theory of valency, though a 

 chemical Ishmael might view it in a different light. 



While engaged in studying the compounds of fluorine, 

 Moissan's interest was aroused in the element boron ; he 

 obtained the amorphous variety in quantity, and caused 

 it to unite with iodine, sulphur and phosphorus ; he 

 examined the action of alkali metals on boric acid, 

 and, as we shall see later, in speaking of the electric 

 furnace, prepared the carbide BC. 



In 1891 the coveted honour of a seat in the Acaddmie 

 des Sciences was conferred upon him in recognition of 

 his brilliant work. Cahours had died. To fill his place 

 the names of Moissan, Grimaux, Ditte, Jungfleisch and 

 Le Bel were submitted to the Comite. After a discussion 

 lasting nearly two hours it was decided to nominate 

 Moissan and Grimaux for election. The latter was 

 defeated by eleven votes, and Moissan became the 

 confrere of Berthelot, Friedel, Schiitzenberger and 

 Troost. 



The difficulty which was now hampering his work was 

 one of temperature ; he required a source of heat greater 

 than that obtainable from the oxyhydrogen flame, and 

 had recourse to the electric arc. In 1892 he devised the 

 electric furnace, by means of which in its more perfect 

 form a temperature of 3500° C. could be readily attained. 

 ■ The first result was the production of uranium from its 

 oxide in fair quantities. .Metals hitherto considered re- 

 fractory yielded at once to the intense heat, and the 

 electric furnace became in his hands the source of good 

 specimens of chromium, tungsten, titanium, molyb- 

 denum, vanadium, zirconium, &c., aH obtained from their 

 oxides by reduction with charcoal. 



In the following year, 1S93, came the production of 

 artificial diamonds, and Moissan's name became the prey 

 of newspaper men and popular lecturers ; chemistry 

 began to appeal to the man in the street. 



Moissan now took up the compounds of carbon with 

 the metals, and obtained a whole series, comprising the 

 carbides of sodium, potassium, calcium, strontium, 

 barium, yttrium, lanthanum, thorium, aluminium, 

 titanium, zirconium, chromium, uranium and manganese, 

 and of the metalloids, boron and silicon. Quite recently 

 he has added the carbides of neo- and praseo-dymium to 

 the list. Proceeding in the same way with silicon and 

 boron, he prepared the silicides of iron, chromium, 

 tungsten, titanium, molybdenum, ^:c., and the borides of 

 iron, nickel, cobalt, titanium, molybdenum, calcium, 

 strontium and barium. 



In 1S98 he succeeded in his efforts to make calcium 



NO. 1 68 I, VOL. 65] 



assume the crystalline form by dissolving it in sodium at 

 a dull red heat, and dissolving away the sodium by 

 absolute alcohol ; from this crystalline variety he was 

 able to pass to the hydride, nitride and phosphide of the 

 element. By the electrolysis of fused calcium iodide he 

 was the first to obtain the metal calcium in a state of 

 purity. 



When this series of experiments is completed, we 

 shall be in a position to generalise from his results. Not 

 the least interesting feature of the work is the bearing 

 it will have on the Periodic classification ; in this 

 connection it should be of supreme importance. 



But for the present we must be content with this 

 necessarily brief rt'sumc of the scientific work of Henri 

 Moissan. ."^s an experimenter he is unrivalled. "J'avais 

 commence Ji manipuler,'' he says, "de I'age de 14 ^ 15 

 ans ; et mes premieres lemons de chiniie, donnees par 

 mon pcre, sont encore gravees dans ma memoire." He 

 is no theorist in the ordinary sense of the word. His 

 work has been confined to the sphere of the purely 

 practical ; and for him a theory exists only that it may 

 be submitted to the test of rigorous experiment, and for 

 the sake of what it leads to. We can conceive of him 

 working out a theory for the origin of diamonds ; we find 

 it difficult to conceive of him formulating a theory for 

 the origin of man. 



Unlike his distinguished compatriots, M. Berthelot 

 and the late C. Friedel, who worked in both fields, 

 organic and inorganic, Henri Moissan has remained true 

 to the enthusiasm inspired by his first great teacher, 

 DeviUe. "Je me suis applique .'i cultiver cette chimie 

 minerale que Ton croyait epuisee, et je pense que mes 

 travaux,ainsi que les belles recherches des savants anglais, 

 ont pu dcmontrer que cette science reserve encore bien 

 des decouvertes a ceux qui voudront I'aimer et I'etudier 

 avec tenacite." " To love it and pursue il with zeal " is 

 the secret of Moissan's success, as it was of that of Davy 

 and Faraday and Lavoisier. 



In the midst of the gayest capital of Europe, but un- 

 touched by all the vicissitudes of its political life, he lives 

 and works. " Ma vie a eu toute la simplicite de ma 

 carriere de professeur, et mon existence s'est partagee, 

 heureuse jusqu'ici, entre mon laboratoire et ma maison." 



We can only wish him a continuance of this happiness, 

 and in his new sphere an equal measure of success. The 

 Science Faculty of the University of Paris is to be con- 

 gratulated on the acquisition of so eloquent and so dis- 

 tinguished a teacher. 



NOTES. 



The Geological Society of London will this year award its 

 medals and funds as follows : — The Wollaslon medal to 

 M. Friedrich Schmidt of St. Petersburg, the Murchison medal to 

 Mr. F. \V. llarmer, and the Lyell medals to Mr. R. Lydekker 

 and Prof. Anton Fritsch, of Prague ; the Wollaslon fund to Mr. 

 L. J. Spencer, the Murchison fund to Mr. T. II. Holland, the 

 Lyell fund to Dr. Wheelton Hind, and the Barlow-Jameson 

 fund to Mr. W. M. Ilutchings. 



PRor. J. M. Marshal!,, who for three years past has been 

 associated with Mr. Bcsanquet in archaeological researches at 

 Athens, has been appointed Director-General of the Arch.vo- 

 logical Survey of India, for a period of five years in the first 

 instance. 



The objects found during the recent excavations at Stone- 

 henge will be on view in the library of the Anthropological 

 Institute, Hanover Square, until January 21. 



.K MEDALLION bust of Sir George .\iry is to be placed in the 

 northeast wall of St. Alphage Parish Church, Greenwich, by 

 his daughters. The bust has been copied from the one in the 

 Royal Observatory, Greenwich. 



