Il\ 



Mav 



1895] 



lYA TURE 



- KUe Mr. Lockyor's Ixrlicf as to their origin, .ind think that a 

 I iiirt generation will speak of the evolution of metals as we 

 ■ « (ki of that of animals, and that olx-serNers will naturally turn 

 • the sun as the field in which this evolution can liest he stu(lie<l. 

 To the alchemists metals were very living indeed ; they treated 

 them as if they were, and had an elal>orate pharinaco]xvia of 

 '■ medicines" which they freely administered to metals in the 

 hope of perfecting their constitution. If the alchemists 

 constantly draw i>arallels between living things anrl metals, it 

 is not because they were ignonint, but because they recognised 

 in' metals the ]X).sscssion of attributes which closely resemble 

 lho.se of organisms. " The first alchemists were gnostics, and 

 the old beliefs of Kgvpt blended with those of Chaldea in the 

 second and third centviries. The old metals of the Egyptians 

 represented men. and this is probably the origin of the komitn- 

 cuius of the middle ages, the notion of the creative (xjwer of 

 metals and that of life being confounde<l in the same symtxjl."^ 

 Thus Alberlus Magnus traces the infl.-.ence of congenital 

 defects in the generati*jn of metals and of animals, and Basil 

 Valentine symbolises the loss of metalline character, which we 

 nitw know is due to <<xidation, to the escape from the metal of 

 an indestructible spirit which flies away and Incomes a soul. 

 I )n llie other hand, the " reduction " of metals from their oxides 

 was supf>osed to give the metals a new existence. A poem- of 

 ihe thirteenth century well emlKidies this Ijelief in the analogies 

 Itetween men and metals, in the quaint lines : — 



" Horns onl Testre comme metaulx. 

 Vie et augment des vegetaulx, 

 Instinct et sens comme les l>ruts. 

 Ksprit comme ange en .'Utril)utes." 



"Men have being" — constitution — like metals; you see how 

 closely metals and life were connected in the minds of the 

 alchemists. 



■' Who said these old renowns, dead long ago, could make me 

 forget the living world?' are words which Browning places in 

 the lips of Paracelsus, and we metallurgists are not likely to 

 forget the living world ; we borrow its definitions, and apply 

 them to our metals. Thus nobility in metals .is in men, means 

 freetlom from liability to tarnish, and we know that the rarer 

 metals, like the rarer virtues, have singular power in enduing 

 their more ordinary associates with firmness, elasticity, strength, 

 and endurance. On the other hand, .some of the less known 

 metals appear to be mere " things" which do not exist for 

 themselves, but only for the sake of other metals to which they 

 can Ix' united. This may, however, only seem to be the case 

 iKcause we a-S yet know so little about them. The question 

 natin-ally arises, how can the analogies between organic and 

 inorganic bodies be traced ? I agree with my colleague at the 

 Ecole des Mines of Paris, Prof. L'rbain le ^'errier, in thinking 

 that it is possible^ to study the biology, the anatomy, and even 

 the |>athology of metals. 



The anatomy of metals — that is, their.structureand framework — 



■> best examined by the aid of the microscope, but the method of 



utographic pyrometry, which I brought before you in a Friday 



uning lecture delivered in 1S91, is rendering admirable service 



n enabling both the biologj' and pathology of metals to be 



uidied, for, just as in biological and ]iathological phenomena 



\\\ja\ functions and changes of tissue are accompanied by 



rise or fall in temperature, so molecular changes in metals are 



iilended with an evolution or .absorption of heat. With the aid 



i<t the recording pyrometer we now "take the tem|K*rature " of a 



mass of metal or alloy in which molecular disturbance is sus- 



KCted to lurk, as surely as a doctor does that of a jxitient in 



> bom febrile symptoms are manifest. 



It has, moreover, long been know 11 thai we can submit a metal 

 ' T an alloy in its normal state to severe stress, record its pow er 

 I endurance, and then, by allowing it to recover from fatigue, 

 liable it to regain some, at le;ist. of its original strength. The human 

 iialogies of metals are really very close indeed, for, as is the case 

 A ith our own mental efl'orts, the internal molecular work which is 

 iiine in tnetiils often strengthens and invigor.ates them. Certain 

 iietals h.ave a double existence, and, according to circumstances, 

 heir liehaviour may be absolutely harmful or entirely beneficial. 



' Iterthelot, Les origines ties aUhiinie, 1885, p. 60. 



- Les Hemonslrances oit la lOtfifllaint tie nature a raic/tiiiiist eryaitt. 

 .\ttributed to Jehan de Meung, who willi Guillaume de Lorris wrote the 

 Rflittan tic la Rnse. M. M^on, the editor of the edition of 1814 of this 

 celel»r;ited wortt, doubts, however, whether the attribution of the cvinfiiainl 

 • fc »zturc to Meuog is correct. 



• •' I.a Metallurgie in France," 1894, p. 2. 



The dualism we so often recognise in human life becomes allotro- 

 pism in metals, and they, strangely enough, seem to be restricterl 

 to a single form of existence if they are absolutely free from con- 

 tamination, for probiibly an absolutely pure metal cannot pass 

 from a normal to an allotropic state. Last, it may be claimed that 

 some metals possess attributes which are closely allied to moral 

 qualities, for, in their relations with other elements, they often 

 tlisplay an amount of discrimination and restraint that would do 

 credit to sentient beings. 



Close as this resemblance Ls, I am far from attributing conscious- 

 ness to metals, as their atomic changes result from the action of 

 external agents, w hile the conduct of conscious l>eings is not deter- 

 mined from without, but from within. I have, however, venturetl 

 to offer the introduction of this lecture in its present form, because 

 any facts which lead us to reflect on the unity of plan in nature, 

 will aid the recognition of the complexity of atomic motion in 

 metals upon which it is needful to insist. 



The foregoing remarks have s|X'cial significance in relatinn 

 to the influence exerted by the rarer metals on the ordinary 

 ones. With exception of the action of carbon upon iron, 

 probably nothing is more remarkable than the action of the rare 

 metals on those which are more common ; but their peculiar 

 influence often involves, as we shall see, the pre.sence of carbon 

 in the alloy. 



Which, then, are the rarer metals, and how may they l>e 

 isolated ? The chemist differs somewhat from the metallurgist 

 as to the application of the word " rare." The chemist thinks of 

 the " rarity " of a comixiund of a metal ; the metallurgist, rather 

 of the difiiculty of isolating the metal from the state of com- 

 bination in which it occurs in nature. 



The chemist in speaking of the reactions of salts of the rarer 

 metals, in view of the wide distribution of limestone and 

 pyrolusite, would hardly think of either calcium or manganese as 

 being among the rarer metals. The metallurgist would consider 

 , pure calcium or pure manganese to be very rare, I have only 

 recently seen comparatively pure specimens of the latter. 



The metals which, for the purposes of this lecture, may be 

 included among the rarer metals are: (i) those of the 

 platinum group, which occur in nature in the metallic state ; 

 and (2I certain metals which in nature are usually found as 

 oxides or in an oxidised form of some kind, and these are 

 chromium, manganese, vanadium, tungsten, titanium, zirconium, 

 uranium, molybdenum (which occurs, however, as sulphide). 

 Incidental reference will be made to nickel and cobalt. 



Of the rare metals of the platinum group I propose to say but 

 little : we are indebted for a magnificent display of them in the 

 librar;- to my friends Messrs. George and Edward Matthey 

 and tJ Mr. Sellon, all memljers of a great firm of metallurgists. 

 Vou should specially look at the splendid mass of palladium, 

 extracted from native gold of the value of ;^2, 500,000, at the 

 melted and rolled iridium, and at the masses of osmiurn and 

 rhodium. No other nation in the world could show such specimens 

 as these, and we are justly proud of them. 



These metals are so interesting anil precious in themselves, 

 that I hope you will not think I am taking a sordid view of them 

 by saying that the contents of the case exhibited in the librar\- 

 arc ci-rtainly not worth less than ten thousand [^xiunds. 



.\s regards the rarer metals w hich are a.s.sociated w ith oxygen, 

 the problem is to remove the oxygen, and this is usually effected 

 either by aflbrding the tixygen an opportunity for uniting wnth 

 another' metal, or by reducing the oxide of the rare metal by 

 carbon, aided by the tearing effect of an electric current. In 

 this crucible there is an intimate mixture, in atomic proportions. 

 of oxide of chromium anil finely divided metallic aluminium. 

 The thermo-junction (a. Fig. i) of the pyrometer which formed 

 the subject of my Last Friday evening lecture here, is placed 

 within thecnicible, B,and the s|)ot of light, c, from the galvano- 

 meter, D, with which it is connected, indicates on the screen that 

 the temperature is gradually rising. \ ou will observe that as 

 soon as the point marked ioio° is reached, energetic action takes 

 place : the temjKrature suddenly rising above the melting-point 

 of platinum, melts the thermo-junction, and the sjxit of light 

 swings violently ; but if the crucible be brokeii open, you will 

 .see that a m.a.ss of metallic chromium has been liberated. 



The use of alkaline metals in separating oxygen froni other 

 metals is well known. I cannot enter into its history here, 

 beyond saying that if I were to do so. frequent references to 



NO. 133 1, VOL. 52] 



