NATURE 



[May 9, 1895 



of ONides in the electric arc are alwa)'s carbides. There are, in 

 fact, some of the rarer metals which we, as yet. can hardly be 

 said to know except as car!>ides. .\s the following ex^xrrinient is 

 the last of the series, I would express my thanks to my assistant. 

 Mr. Stansficld. fur the great care he has bestowed in order 

 to ensure their success. Here is the carbide of calcium 

 which is produced by heating lime and carlxin in the electric arc. 

 It possesses great chemical activity, for if it is placed in water 

 the calcium seizes the oxygen of the water, while the carbon also 

 combines with the hydrogen, and acetylene is the result, which 

 bums brilliantly. [Kxi>erimenl shown.) If the carbide of calcium 

 lie placed in chlorine water, enl smelling chloride of carbon is 

 formed. 



In studying the relations of the rarer metals to iron, it is 

 impossible to dissticiale them from the influence exerted by the 

 simultaneous pre^ience of carUkn : but carbon is a protean element 

 — it may be disstilved in iri>n,or it may exist in iron in any of the 

 varietl forms in which we know it when il is free. Matthiessen, 

 the great aulhorily en alloys, actually writes of the " carl>on-iron 

 alloys." I do not hesitate therefore, on the ground that the 

 subject might ap|K*;ir to be without the limits of the title of this 

 lecture, to jioint to one other result which has licen achieved by 

 M. .Moissan. Here i> a fragment of pig irtm highly carburised : 

 melt it in the electric arc in the presence of carbon, and cool the 

 molten metal siuhlenly, preferably by plunging it into molten 

 lead. .\s cast iron c\|Kinds on solidification, the liule mass will 

 liecume solid at its surface and will contract ; but when, in turn, 

 the -till fluid m.xss in the interior cools, it expands against the 

 solid crust, and consetjuently .solidifies under great pressure. 

 f)is.solve such a mass of airburised iron in nitric acid to which 

 chlorate of |K)tash Is added ; treat the residue with caustic 

 pota.sh, submit it to the prolonged attack of hydrofluoric acid, 

 then to boiling sidphuric .acid, and finally fuse il with i>ot,ash, to 



These relate to the siitgular attitude towards metallurgical 

 research maintained by tho.se who are in a jio.sition to iironiote 

 the advancement of science in this coinitry. Statements resj^ect- 

 ing the change of shining graphite into brilliant diamond are 

 receiveii with aiiprecialive interest ; but, on the other hand, the 

 vast ini|Kirtance of eft'ecting similar molecular changes in metals 

 is ignored. 



We m.ay .acknowledge that "no n,ation of modern times h.as 

 done so much practical work in the world as ourselves, none has 

 applied itself so conspicuously or m ith such conspicuous success 

 to the indefatigable pursuit of all those branches of human 

 knowledge which give to man bis mastery over matter." ' But it 

 is typical of our i>ecullar Hrllish methotl of advance to dismiss 

 all metallurgical questions as " industrial," and leave their con- 

 sideration to private enterprise. 



We are, fortunately, to spend, I believe, eighteen millions this 

 year on our Navy, and yet the nation only endows experimental 

 research in all branches <•>{ science with four thousand jxurnds. 

 We rightly ai\d gladly sjumkI a million on the Mai^iiifiirnl, and 

 then stand by while manufacturers compete ft)r the privilege of 

 ]>roviding her with the armour-plate which is to .sa\e her from 

 disaljlement or destruction. We as a nation are fully holding 

 our own in metallurgical progress, but we might be iloing so 

 much more. Why are so few workers studying the rarer metals 

 and their alloys? Why is the crucible so often aliandoned for 

 the test-tube? Is not the investigation of the properties of 

 alloys precious for its own sake, or is our faith in the fruitfulness 

 of the results of metallurgical investigation so weak that, in 

 its ca.sc, the sub.stance of things hoped for remains unsought for 

 and unseen in the depths of obscurity in which metals are still 

 left ? 



We nuisl go back to the traditions of l-'araday, who was the 

 first to investigate the Influence of the rarer metals upon iron. 





° -^ Q G F 



Vu„ 8. — Preparations fur ihc microscoiM: ufLHanionds .ind otlicr forms of cartjon oWlaiiicd from carljuriscil iiini. 



remove any traces of carbide of silicon, and you have carlwn left, 

 but — in the form i^i tiiamomis. 



If you will not exjicct to see too much, I will show you some 

 diamonds I have pre|>ared by strictly following the directions of 

 M. Mois.san. As he |Kilnts out, lhe.se diamonds, being produced 

 under stress, .are not entirely without .action on polarised light, 

 .and they have, s^unetimes, the singular proiKrty of flying to 

 pieces like Rupert's dro[)s when they are moimted as pre|jarations 

 for the microscope. [The Images of many small specimens were 

 projected on the .screen from the microscope, and (Kig. S, K) 

 shows a .sketch of one of these. The largest diamond yet pro- 

 duced by M. Moissan. Is 0'5 millimetre in diameter.] 



A (Fig. 8) represent- the rounded, pitted surface of a <ll,aniond, 

 and B a cry.stal of fliamond from the series prj|)ared by M. 

 Mojs.san, drawings i>f which Illustrate his [laper. ' The re.st of 

 the specimens, < to k, were obtained by myself by the alil of his 

 methrKl as aUne descrilieil. •' represents a dendritic growth 

 ap|iarently com|Kised of hex.agonal plates of graphite, while I> is 

 a s|H.'cimen of much Interest, as it appears to be a hollow sphere 

 '>f graphitic carUin, partially crushed in. .Such examples are 

 very numerous, and their surfaces are covered with mimile rouml 

 graphitic pits aiul prominences of great brilliancy. Specimen V. 

 (which, as alreaily staled, was one o( a series shown to the 

 audience) is a broken crystal, jirobibly a tetrahedron, and Is the 

 licsl cr^'ilallised s|KTlmen of diainonil I have a.s yet .succeeded in 

 prcfKinng. Nlinute diamonfis, similar to A, may be reaillly pro- 

 <luce<l, and brilliant fragments, with the lamella structure shown 

 in V . arc also often met with. 



The cloAC as.v>ciatlon of the rarer metals and carUtn and their 

 intimate rclntlim- with carlnm, when Ihey arc hidden with it in 

 inm. enabled me (<> refer l» the pr<Mluclioii of the diamond, and 

 afford a l*si» for the few observations I wtiuld offer in conclusion. 



* Vt^mflfi rfHiltit, v.>l. civiii., 1S94, p. \n, 



NO. 1.132. VOL. 52] 



and to prepare the nickel-iron series of which so much has since 

 been heard. He did not despise research which might possibly 

 tend to useful results, but joyously records his satisfaction at 

 the fact that a generous gift from Wollaston of certain of the 

 " .scarce and more valuable metals" en.alik'd him to transfer his 

 experiments from the lalioratory in .-\lbcmarle .Street to the works 

 of a manufacturer at Shetheltl. 



Kar.aday not only began the research I am pleading for to. night, 

 but he gave us the germ of the dynamo, by the aid of which, as 

 we have seen, the rarer metals maybe isolated. If it is a source 

 of national pride that research should be eiulowed apart from the 

 national expenditure, let us, while remembering our res|ioiisi- 

 blllties, rest In the hope that metallurgy will be well represented 

 in the Laborat'iry which private nnnilficence Is to place side by 

 sl<le with our historic Koyal InslitiUion. 



I-.LECTRICITV AND OPTICS. 



A MI-.MOlK of singular interest, and one of which il would 

 •'*■ be well if the contents could be made more readily 

 accessible to students In this country, has lately been published 

 by I'nif. Kighi.'' .\mong the numerous papers publisheil during 

 the last Iwenly years by j'rof. Kighl there are several (on electric 

 discharges, on electric shadows aiui photo-electric phenomena) 

 which inillcate his InieresI In the relallcms between light and 

 eleclriclty. Since Hertz, succeeded in obtaining rays of electric 

 force, anil deinonslraled the reflection, refraction and interference 

 of electric radiation, other experimenters have endeavoured to 

 exteiirl and complete the analogy between electromagnetic and 

 linninous vibrations. Thus Lodge aiul Howard showed that 

 electric radiation couKI be concentrated by means of large lenses ; 



' I'hf I'iitirt, Kchruary 22, 1895. 



^ " .Siille o-,t:ill;u;oiii cicttrichc a piccola liitij;bc/7.'i d'oiula e sul lore, 

 impicKo iiclla pr,Hlu/ioiic di fcnomcni nnalofjhie ai principali fcnotllciit dctl' 

 iiltlta. * (I1.iI..i;ti.i : i8d4). 



