November 17, 1904] 



NATURE 



05 



mo-it of the older buildings of the university. The group of 

 medical school buildings now in use have cost altogether 

 ^bout 80,000/.. including, with the building opened on 

 Saturday the Thompson- Vates laboratory and the Johnston 

 laboratory. The Chancellor of the university, Lord Derby, 

 formally 'inaugurated the new buildings on the same after- 

 noon as Lord Kelvin opened the new university laboratory 

 for physics. With these fresh additions to its accommo- 

 <iation'and teaching equipment, and with the fine new 

 laboratories for zoology and for electrical engineermg novv 

 rapidly nearing completion, the University of Liverpool will 

 rank among the best provided university institutions in the 

 <?ountrv. 



PROF. MENDELEEFF ON THE CHEMICAL 



ELEMENTS. 

 "PHE last half-volume (eightieth) of the new Russian 

 ■*■ ■' Encyclopaedic Dictionary" contains a remarkable 

 paper by Prof. Mendel^eff on the chemical elements, of 

 which the following is a slightly abridged translation. 

 Together with the articles on matter and on the periodic 

 law, which Mendeleeff contributed to previous issues of 

 the same dictionary, and a paper, " An .Attempt at a 

 Chemical Comprehension of the World's Ether," published 

 in a Russian review, this article represents the fundamental 

 physical and chemical conceptions of the great chemist 

 as they now appear in connection with the discoveries of 

 recent years. 



" Human thought," he begins, " has always endeavoured 

 to simplify the immense variety of phenomena and sub- 

 stances in nature by admitting, if not the full unity of the 

 fundamental elements (Democritus, E{)icurus), at least 

 the existence of a limited number of elements capable of 

 producing all the variety of substances. In antiquity this 

 tendency often resulted even in confusing the phenomena 

 with the substances (earth, water, air, and fire)." 

 Since the time of Lavoisier such a confusion has become 

 certainly impossible : the substances are sharply separated 

 from the phenomena which are associated with them. 

 Of course, there may be partial returns to the old 

 view. " However," Mendeleeff continues, " the solidity 

 of the now prevailing conception as to the profound 

 difference existing between substances and phenomena is 

 the result of such a mass of coordinated knowledge that 

 it cannot be shattered in the least even if a small portion of 

 the men of science return to the " dynamism " of old which 

 ■endeavoured to represent matter also as one of the forms of 

 phenomena. Consequently we are bound now to recognise 

 the substances (the masses) and the phenomena (the move- 

 ments) as two quite separate, independent categories, such 

 as space and time, the substance of which our thought 

 lias not yet penetrated, but without which it cannot work. 

 Thus, for example, we are far yet from understanding 

 the cause of gravitation, but with its aid we understand 

 many phenomena, even though up till now it is not 

 <|uite evident whether attraction acts through the aid of 

 an intervening medium or represents a fundamental force 

 which acts at a distance. Progress in the understanding 

 of nature depends, therefore, not upon our reducing every- 

 thing to one final conception — to one ' principle of all 

 principles ' — but in reducing the great variety of substances 

 -and phenomena which act upon our senses to a small number 

 of recognised fundamental conceptions, even though these 

 last be disconnected. One of such conceptions is that of 

 the recognised chemical elements. 



*' The simplest wav of conceiving matter in this case is 

 to consider it as the result of combinations of elements 

 which themselves are matter ; and the phenomena as the 

 results of movements which are the property of these 

 elements or their aggregations. It was from this point 

 of view that the conceptions were elaborated as to the 

 distinction, not only between phenomena and substances, 

 l)ut also between simple bodies and elements ; because the 

 conception of a simple body implies the idea of an im- 

 possibility of transforming certain bodies into other bodies, 

 while the conception of a chemical element is merely deter- 

 mined by the desire of diminishing the number of sub- 

 stances which are required for explaining the great variety 

 of the latter." 



NO. 1829, VOL. 71] 



Mendeleeff passes next to the so-called " rare " elements. 

 Leaving aside historical details concerning them, he re- 

 marks that it is the more necessary to dwell upon them 

 as they complete to a great extent our knowledge of the 

 periodic law. "Our information about them," he con- 

 tinues, " can also, in our opinion, contribute towards 

 explaining the relations between the phenomena and the 

 substances in nature ; because for the understanding of a 

 multitude of natural phenomena it is necessary to res.irt 

 to the conception of the so-called luminiferous ether, 

 which by all means must be considered as a ponderaole 

 substance, and consequeijtly must have its place in the 

 system of elements, inasmuch as it reminds us of the proper- 

 ties of helium, argon, and other similar elements. The 

 conception of the ether was resorted to at the outset ex- 

 clusively for explaining the phenomena of light, which, as 

 is know'n, can be best understood as the result of vibrations 

 of the ether. However, later on, ether, considered as being 

 distributed throughout the universe, was resorted to in order 

 to explain, not only electrical phenomena, but also gravita- 

 tion itself.' In consequence of that, a very great importance 

 has to be attributed to the ether : and as it cannot be con- 

 sidered as anything but ponderable matter, we are bound 

 to apply to it'all the conceptions which we apply to matter 

 in general, including also the chemical relations. But as, 

 at the same time, we are bound to admit that this matter 

 is not only distributed throughout stellar space (in 

 order to explain the light which reaches us from the stars), 

 but also penetrates all other substances; and as also \ve 

 must admit that the ether has no capacity of entering into 

 chemical reactions, or of undergoing any sort of chemical 

 condensation, therefore the above mentioned elements, 

 helium and argon, which are characterised precisely by the 

 absence of that property of entering into chemical reactions 

 with other substances, show in this respect a certain 

 similarity with the ether.' " 



Referring further to radium, Mendeleeff remarks that 

 there can be no doubt as to its being a separate element, 

 extremely rare in nature. .As to the emanation of helium 

 by radium and the presence of the helium spectrum in the 

 spectrum of radium, he explains these facts by the occlusion 

 of helium in a compound of radium, and considers that 

 " nothing gives us reason to think that radium should be 

 transformed into helium." "Notwithstanding the ex- 

 tremely small quantities of radium occurring in nature 

 Madame Curie has succeeded in obtaining a compound of 

 it and in establishing its kinship with barium, as also in 

 finding its atomic weight to be near 224, which permits us 

 to complete the periodic system of elements^ by placing 

 radium in the second group, in the 12th row, in which we 

 have already thorium and^ uranium, the ores of which are 

 possessed of radio-activity." 



" As to argon and its congeners — neon, krypton, .Tnd 

 xenon— these simple gases, discovered by Ramsay, differ 

 from all the known elements in that, up till now, not- 

 withstanding the most varied attempts, they could not 

 be brought into combination with any other substance, or 

 with each other. This gives them a separate place, quite 

 distinct from all other known elements in the periodic 

 system and induces us to complete the system by a new 

 separate group, the group zero, which precedes groiip 1., 

 the representatives of which are hydrogen, lithium, sodium, 

 and so on. 



" The placing of these elements in a new group is 

 fully supported by the atomic weights which are deduced 

 for 'these gases on the basis of their densities, if we admit 

 that the molecule of each of them contains but one atom. 



1 " ^hnnt ihi'i resemWance betwssn areon and helium and the substance 

 of the' weld's ether T have already written in a sep.r..e articee^^^^^^ 

 'An Attempt at a Chemicil Cnmnrehension of the F.ther, in the review 

 M"ssn,^.,-':,„.f Utrarr of Sclf-F.d,ua,ion, ■n.the %« f-/ """■h";, ^"I 

 T^^-> ThU arfirle wa-^ translafed into Herman in the t^rotitetiti-Hs m 100, 

 bv M Tshu?ok,and into Eni;llsh bv M. Kamenskiy under .he ..tie ' A 

 Chem cal Concpption of the Ether' (Lonemans, Green and Co., London, 

 TnrT.T I nui^t however, remark that the German translation is a complete 

 one but that .'he editors of .he English translation have om.tted .he intro- 

 ductory general philosophical remarks about 'he fundamental d.stiiict.on 

 between substances (masses), forces (energy), and SD.rit. Iti.s omission 

 deprives the article of .he realistic tneaning wh.ch I .mended to g.ve ,t 

 bv introducing ether into the system of elements. . v., < j: ,„ 



2 " Some later researches lead us to believe that the atomic weight of radium 

 is slightly above the figure found by Madame Curie, but .t seems to me mat 

 it still remains doubtful whether the conclusion of Madame Cur.e has to 

 be altered."' 



