^34 



NA TURE 



[June 8, 1893 



iiiaximus, Thomps.) inhabiting Pecten were obtained, along 

 with many other Copepoda which have not yet been examined." 



Two further papers upon his researches with the electric 

 furnace are contributed by M. Moissan to the current number of 

 the Comptes Rendus. In the first it is shown that crystals of 

 quartz and zircon are almost instantly fused at the high tem- 

 perature of a powerful electric arc, the liquids brought to 

 vigorous ebullition in a few moments and actually distilled, 

 passing over into the receiver in the form of a dense fume. 

 M. Moissan further demonstrates how easy it is at this high 

 temperature to obtain pure zirconium and pure silicon by re- 

 duction of the liquefied oxides with carbon. The current em- 

 ployed was one of 360 amperes. When fragments of rock 

 crystal were placed in the crucible of the furnace and subjected 

 % to the arc they rapidly melted, and in seven minutes the liquid 

 boiled vigorously ; the vapour of silicon dioxide which escaped 

 condensed in the cooler portion of the furnace to a bluish-white 

 fume, which deposited in the receiver in the form of small 

 opalescent spheres, visible to the unaided eye. These spheres of 

 silica were solid throughout, and usually exhibited a depression 

 at some portion of the surface, indicating contraction upon pass- 

 ing from the liquid to the solid state. They were readily soluble 

 in hydrofluoric acid. It is of interest that M. Moissan has dis- 

 covered similar opalescent spheres of silica upon glass globes 

 which have been employed in electric lighting to diffuse the 

 light from arc lamps, indicating that slow volatilisation of the 

 silica of the glass had occurred. It is doubtless to this cause 

 that the opalescence which usually occurs after such globes have 

 been in use for some time is due. The specific gravity of the 

 spheres is 2 '4, slightly less than that of quartz. At the tempera- 

 ture of the arc given by 360 amperes liquid silica is very readily 

 reduced by carbon, a crystalline regulus of silicon being obtained 

 containing more or less carbon. 



When zircons or any other form of zirconia are submitted to 

 the high temperature of the same arc they lilcewise fuse, and in 



about ten minutes the liquid boils vigorously, and zirconium 

 oxide passes over as a white fume into the receiver, where it 

 condenses in the form of a white powder. Any liquid remain- 

 ing in the crucible after switching off the current solidifies to a 



crystalline mass, and scattered about the walls of the furnace 

 numerous perfect little artificial zircons are observed, identical 

 n colour, lustre, and other properties with natural zircons. 

 Both these and the powder condensed in the receiver readily 

 scratch glass. Liquid zirconia, like silica, is readily reduced by 

 carbon. If the oxide is fused by the arc in a carbon crucible, 

 a button of metallic zirconium is found at the close of the 

 operation beneath the residual solidified zirconia. If zirconia 

 is mixed with powdered carbon a metal is obtained containing 

 4-5 per cent, of carbon. This carbide can be refined by re- 

 melting with more zirconia when the pure metal is obtained. I 

 Zirconium is a very hard metal, readily scratching glass and 

 ruby. Its density is 4^25. 



The second paper of M. Moissan describes the preparation 

 of metallic tungsten, molybdenum, and vanadium. Tungsten 

 is leadily obtained in the form of powder by reduction of heated 

 tungstic acid in a current of hydrogen, but the powder thus 

 obtained has been hitherto found to be practically infusible. 

 M. Moissan now shows that tungsten may be readily prepared 

 in solid ingots in the electric furnace. A mixture of tungstic 

 acid and carbon is placed in the crucible, and after ten minutes' 

 subjection to an arc of the tension above stated a button of 

 over a hundred grams of the metal is produced. If care has 

 been taken to ensure excess of tungstic acid, pure tungsten is 



btained in the one operation. Otherwise a carbide is obtained 

 which requires refining by re-melting with a further quantity of 

 tungstic acid. The tungsten thus obtained is a very brilliant 



NO. 1232, VOL. 48] 



metal of specific gravity 187. M. Moissan has further observed" 

 that if a much more powerful arc is employed, the percentage of 

 carbon in the carbide of tangslen first obtained is very largely 

 increased. Thus when a current of 1000 amperes was employed 

 the percentage of carbon rose to 18, indicating an attempt to 

 form a true binary compound. Metallic molybdenum has like- 

 wise been obtained by M. Moissan by the reduction of its oxide 

 with powdered charcoal at the temperature of the arc afforded 

 by a current of 360 amperes. The meta! is not, however, quite 

 free from carbon, and requires refining. 



The preparation of metallic vanadium has presented con- 

 siderable difficulty. It will be remembered that Sir Henry 

 Roscoe found it impracticable to reduce vanadic acid by carbon, 

 and eventually isolated the pure metal by reduction of the 

 dichloride in a stream of hydrogen. M. Moissan finds that even 

 after twenty minutes' action of the arc from the 360 amperes 

 Current, only a trace of reduction is apparent at the surface of 

 the mixture of oxide and charcoal. Upon increasing the tension 

 of the arc by employing a current of a thousand amperes com- 

 plete reduction occurs, but the metal produced combines, as in 

 the case of tungsten, with a large quantity of carbon. It would 

 appear, therefore, that at this high temperature these refractory 

 metals combine with carbon to form definite binary compounds. 



Notes from the Marine Biological Station, Plymouth. — 

 Last week's captures include the Actinians Sagaiiia miniata 

 and venusla, the Nemertines Atnphiporus hastatus and Mala- 

 cobdella grossa, the Polychaete Myrianida maculata (with a 

 posteriorly proliferated chain of buds), and the Schizopods 

 Siriella frontalis SlX^A jaltensis, the latter species in considerable 

 numbers. Floating Ccelenterates have been particularly plenti- 

 ful. Medusae of Aurelia aurita (now 4 to 7 ins. in diameter) 

 have frequently been noticed. The Anthomedusje have been 

 represented by Sarsia tubulosa, Bougainvillea ramosa, and, 

 more plentifully, by Amphinevia Titania ; the Leptomedusa; by 

 countless numbers of Phialidiuin variabile, together witii a 

 smaller proportion of Thaumantias Thompsoni (Forbes) and 

 Laodice cruciala, Ag. (= T. pilosella, Forbes). A few young 

 Clytia medusae have been occasionally taken, but Obtlia 

 medusae have been very scarce. The Ctenophore Hormiphora 

 phimoia, in various stages of growth, is now abundant. Several 

 specimens of the parasitic larva of the Actinian Hakainpa 

 chrysanthellum have been taken. The beautiful veliger Echino- 

 spira diaphana lias once been noticed ; larva; of the Crustacean 

 Porccllana are plentiful. The following animals are now breed- 

 ing : — The Hydroid Clava cornea, the Mollusca J/«;vjr«-2«a«»i 

 and Aplysia punctata, the Schizopoda Macromyiis inermis and 

 Siriella jaltensis, the Decapod Palainonetes vulgaris, and the 

 Echinoderm Astcrina gibbosa. 



The additions to the Zoological Society's Gardens during the 

 past week include a Barbary Ape {Macacus inuus, 9 ) from 

 North Africa, presented by Mr. A. G. F. Dashwood ; a 

 Suricate (Sw icala tetradactyla) from South Africa, presented by 

 Mr. L. V. Harcourt ; ihret Chmese Q^aaWs (Cotnritix chinensis, 

 (J 9 9 ) from China, presented by Mr. W. J. Ingram ; two 

 Kingfishers {Alcedo ispida) British, presented by Mr. A. K. 

 Dixon ; a Harlequin Snake (Elaps fulvins) from Florida, pre- 

 sented by Mr. C. Ernest Brewerton ; a Horned Lizard (Phry- 

 nosoma cornutum) from Texas, presented by Mr. J. Harland 

 Coates ; a Sykes's Monkey {Cercopithecus albigularis, 9 ) from 

 East Africa, a Leucoryx (Oryx Isucoryx, 9 ) from North Africa, 

 a Mexican Deer (Cariacns mcxicanus, i) from Mexico, a 

 Malayan Tapir ( Tapirus indicus, i ) from Malacca, two Common 

 Cassowaries {Casuariiis galeatus, jr.) from Ceram, a Leopard 

 Tortoise {'Pestudo pardalis), two Derbian Zonures {Zonurus 

 derbianus) from South Africa, deposited ; two Brazilian Cari- 

 amas [Carianm crislata) from Brazil, four Black-tailed Godwils 



