i6 



.\'. / Ti Rli 



[MaV 2. 1S95 



the honoured names of Berzelius, Wohler, and Winkler would 

 be demande<l.' 



Mr. \autin has recently shown that granulated aluminium 

 may readily be prepared, and that it renders great ser\ice 

 when employed as a reducing agent. He has lent me many 

 specimens of rarer metals which have been reduced to the metallic 

 state by the aid of this finely-granulated aluminium ; and I am 

 indebtetl to his assistant, .Mr. I'icard, who was lately one of my 

 own students at the Royal School of Mines, for aid in the pre- 

 paration of certain other specimens which have been isolated in 

 my laboratory at the .Mint. 



The experiment you have just seen enables me to justify- a 

 statement I made respecting the discriminating action which 

 certain metals appear to e.\ert. The relation of aluminium to 

 other metals is very singuLir. When, for instance, a small 

 quantity of aluminium Is present in cast-iron, it protects the 

 alicon, manganese, and carlxin from oxidation." The presence 

 of silicon in aluminium greatly adds to the brilliancy with which 

 aluminium itself oxidises and bums.' It is also asserted that 

 aluminium, even in small quantity, exerts a powerful protective 

 action against the oxidation of the silver-zinc alloy which is the 

 result of the desilverisation of lead by zinc. 



Moreover, heat aluminium in mass to redness in air, where 

 oxygen may lie had freely, and a film of oxide which is formed 

 will protect the mass from further oxidation. On the other 

 hand, if finely divided aluminium finds itself in the presence of 

 an oxide of a rare metal, at an elevated temi>erature, it at once 

 acts with energy and promptitude, and releases the rare metal 

 from the bondage of oxidation. I trust, therefore, you will con- 

 sider my claim that a metal may possess moral attributes has 



Kio. 1 



been justified. .Aluminium, moreover, retains the oxygen it has 

 acquired with great fidelity, and will only part with it again at 

 very high icni|x-ratures, under the influence of the electric arc in 

 ihe presence of carlKm. 



[A suitable mixture of red-lead and aluminium was placed in a 

 small crucible heated in a wind furnace, and in two minutes an 

 explosion announce<l the termination of the experiment. The 

 "rucible was shaltere<l to fragments.] 



The aluminium loudly protests, as it were, against being 

 entrustctl with such an easy task, as the heat engendered by its 

 oxidation liad not to Ix: used in melting a dilficultly fusible metal 

 like chromium, Ihe melting |inint of which is higher than IhnI 

 •if platinum. 



It is admitted that a metal will al>slract oxygen from another metal 

 if Ihe ria' lion is more exothermic than that by which the oxide 

 l'» Ix- '' '1. was originally formed. The heal of formation 



*tf alit 1 ralorie-., that of oxide r>f leaii is 51 calories ; so 



that II ....^ •.\|K;cted that metallic aluminium, at an elevated 



temperature, would readily re<lucc oxide of lead In (he metallic 

 stale. 



The last ex|ierimcnt, however, proveil that the reduction of 

 oxide of lead by aluminum is effected with explosive violence, 

 Ihc temperature engendered by the rc<luction being sufliciently 

 high to volatilise the lead. Kx|)eriments of my own show that 



K, Keller, on ihc reduction of oxides of 

 fniind in Ihc JoMmai iif ihc Amcricnn 

 ..p. 833. 



I A., 

 incl.-.l- 

 Chcnj" 



I HmU. :„>.. Lk 



«i. 1B94, p. 377. 

 ' ** Dine l^^onn ^ur lev .M^lnux," part ii. 1891, p. ao6. 



the explosion takes place with much ihsruiHive |x)wer when 

 aluminium reacts on oxide of lead 111 T'tic/w, and that if coarsely 

 ground, fused litharge be substituted for red lead, the aition is 

 only accomianied by a rushing sound. The result is, therefore, 

 much influenced by the rapidity with which the reaction can Ih" 

 transmitted throughout the mass. It is this kind of cx|)erinieni 

 which makes us turn with such vivid interest to the teaching ol 

 the school of St. Claire Devillc, the members of which have ren 

 dered .such splendid services to physics and metallurgy. They il< 

 not advocate the employment ol the mechanism ol nulecules ami 

 atoms in dealing with chemical problems, but would simply 

 accumulate evidence as to the physical circumstances under 

 which chemical comliiiiati<m and dissoriatiim take il.ace, viewing 

 these as belonging tothesamecla.ss o( phemmiena as solidification, 

 fusion, contlensation, and eva[ioration. They do not even insist 

 upon the view that matter is minutely granular, Imt in all cases 

 of change of stale, make calculations on the basis of work done, 

 viewing changed " internal energy " as a quanlity which shoulil 

 reapixjar when the system returns to the initial state. 



A verse, of some historical interest, may appe.il to them. Ii 

 occurs in an old |K)eni to which I have already referred as being 

 connected with the Komaii lir At A'tiv. and it expresses nature's 

 protest against those who attempt to imitate her works by the iisv 

 of mechanical melh<xis. The "argument *' runs thus : — 



•' t^onime ii.'itiire ^e coinphuru. 

 Kt dit S.-1 doulciir ct son plaint, 

 .\ ung sot sofllcur sophistit)Uc, 

 Qui n'tisc que d'nri mt^h.iniquc." 



If the " use of mechanical art " includes the study of chemistry 

 on the basis of the mechanics of the atoms, I may be permitted 

 to offer the modern school the following rendering ol nature"^ 

 plaint : — 



'* How nature sighs without restraint. 

 .•\nd KricvinK makes lier s;ul compliiint 

 Against the nubile sophistry 

 Which trusts atomic thcor>'." 



.tVn explosion such as is produced when aluminium and osiii. 

 of lead are heated in presence of each other, which suggested 

 the reference to the old French verse, does not often occur, a- 

 in most cases the retluction of the rarer metals by aluminiuin 

 is efl'ected quietly. 



Zirconium is a metal which may be .so reduced. I have in 

 this way pre|xired small ijiiantities of zirconium from its oxide, 

 and have formetl a greenish alloy of extraordinary strength l>\ 

 the .ad Mtion of 'n [ler cent, of it to gold, and there are man> 

 circumstances which lead to the belief that the future of zirconium 

 will be brilliant and useful. I have reduced vanadium and uranium 

 from its oxide by means of aluminium its well .is manganese, 

 which is easy, and titanium, which is more diflicult. Tungsten, 

 in fine specimens, is al.so before you, and allusion will be made 

 subsetjuenlly to the uses t»f these metals. At present I wouhi 

 draw your attention to some properties of titanium which arc ol 

 special interest. It burns with biilliant sparks in air ; and as fe» 

 of us have seen titanium burn, it may be well to burn a little i:i 

 this flame. [Kxperimenl performed. ) Titanium ap|Kars to be, from 

 the recent experiments of M. Moissan, the most iliflicullly fusiliK 

 metal known ; but it has the singular propeily of binning in 

 nitrogen— it presents, in fact, the only known instance of vivid 

 combustion in nitrogen.' 



Titanium may be readily rerluceil from its oxide by the aid ol 

 aluminium. Here are considerable masses, sufliciently pure fiir 

 many piir|x>scs, which I have recently prepared in view of this 

 lecture. 



The other method by which the rarer metals may be isolnteil 

 is that which involves the use of the electrical furnace. In thi* 

 connection the name of Sir W. .Siemens should not In 

 forgotten. He de.scribed the use of the electric arc-furnaci 

 in which the i-arbons were arranged vertically, the 

 lower carlxjn being replaced by a carbon crucible, antl 

 in 1882 he melted in such a fiirnace no less than ten |xiunds of 

 platinum iliiring an experiment at which I had Ihe gooil fortune 

 to assist. It may fairly be claimed that the large linnaces with 

 a vertical carbon in which aluminium antl other metals are now 

 reiluced by the combined electrolytic action antl tearing 

 tempemlure of the arc, are the direct oiitcrmie of the work of 

 I Siemens. 



In the development of the use of the electric arc for the 

 isolation of Ihe nire, ilifficullly fusible, metals Moi.ss.ar staniK 



I I l<urd Knylcich h.is since sinlc<l thai titanium does not fu>tn1>inc with 

 arKon ; and .M. (■unl/ iKiinIs nui iliat lilhintn in comhinitlK with nitrogen 

 prtHlllces inc.-initrurcnrt . 



NO. I. VI I, VOL. 52] 



