June 2, 1892J 



NA TURE 



m 



unknown in the scientific world, and in which the results of 

 original scientific research would scarcely be sought for. 



Without venturing to enter into the details of these researches, 

 I may mention that experimental evidence favoured the con- 

 clusion that the carbon-impregnation of an iron ore by dissocia- 

 tion of carbonic oxide takes place at as low a temperature as 

 de-oxidation, which, in the case of Cleveland ore, occurs at 200° 

 to 210° C. {392° to 410° F.), and that freshly reduced spongy 

 iron, at about that temperature, reduces carbon from carbonic 

 oxide to an extent corresponding to 20-24 per cent, of its weight, 

 but that, as the temperature approaches a red heat, thedepo>itijn 

 of carbon diminishes considerably in amount. 



The results of many experiments with other metals and their 

 oxides showed that zinc, tin, chromium, and silicon, and their 

 oxides are neither reduced by carbonic oxide at a temperature of 

 about 420° (that of melted zinc), nor give rise to deposition of 

 carbon ; that copper and lead are reduced at temperatures up to 

 a red heat, without deposition of carbon ; that the higher man- 

 gnnese oxides are reduced to protoxide below a red heat without 

 impregnation by carbon ; but that nickel, and in a smaller degree 

 cobalt, suffer reduction from their oxides, with deposition of 

 carbon. 



Sir Lowthian Bell, while conducting his experiments at tem- 

 peratures considerably below those prevailing at the particular 

 positions in the blast furnace where the production of pig 

 iron was believed to be effected, did not have recourse to so low 

 a temperature as that at which Messrs. Mond, Langer, and 

 Quincke, after having demonstrated (what appeared, in the 

 absence of an acquaintance with Bell's results, a novel observa- 

 tion) that carbon was separated from carbonic oxide by passing 

 the gas over nickel at a high temperature, found that this metal 

 actually entered into the composition of the gas. Thus they 

 started fr >m the point, in this particular direction, up to which 

 Sir Lowthian Bell had carried his observations twenty years 

 previously, and obtained the remarkable nickel-carbon-oxide 

 compound referred to by me in my address last year, which 

 they have since succeeded in producing upon so considerable a 

 scale as to afford prospect of its acquiring industrial importance. 



In the description of their earliest results, they stated that 

 attempts to produce similar combinations of carbon oxide with 

 other metals, including iron, had failed. By persevering with 

 research in many very varied directions, and especially with iron, 

 they at length succeeded in volatilizing notable, although small, 

 quantities of the latter metal in a current of carbonic oxide, by 

 using the finely-divided pure iron obtained by reducing the 

 oxalate in a current of hydrogen at the lowest possible tempera- 

 ture (about 400° C), by allowing the product to cool in hydrogen 

 to 80°, and then by passing a current of carbinic oxide over the 

 spmgy metal. The gas, after this treatment, was found to 

 impart a yellow c ilour to a colourless flame, and if conducted 

 through glass tubes heated to between 200° and 350° C, it 

 deposited a metallic mirror ; at a higher temperature it fur- 

 nished black flakes, which analysis sh >wed to contain 79*30 per 

 cent, of carbon. The quantity of iron- and carbon-oxide com- 

 pound produced in this way was very small ; by passing 2^ 

 litres of carbonic oxide per hour over the metal (the latter being 

 from time to time rehea'ed in a current of hydrogen), the issuing 

 gas contained not more than o"Oi grm. of iron, equal to less 

 than 2 c.c. of the gaseous iron- compound in a litre of the 

 carbonic oxide. 



The gas-mixture, when passed through benzine or heavy 

 mineral- or tar- oils, was partially deprived of the iron com- 

 pound, and the result of examination of solutions of this kind 

 led to the conclusion that the gaseous iron combination, 

 analogous in composition to the nickel-carbonoxide compound 

 (or nickel-tetra-carbonyl), had been found, and that its formula 

 was Fe(C0)4. 



In continuing their researches, Mr. Mond and Dr. Langer 

 have succeeded in obtaining the iron compound in the form of a 

 liquid of spec. grav. 1-4664 (at 18° C), which distils without 

 decomposition at io2'-8 C, and solidifies below 21° into yellow 

 needle-shaped crystals. It is slowly decomposed by exposure 

 to air, and when its vapour is heated to 180°, it is completely 

 decomposed into iron and carbonic oxide. Analysis and the 

 determination of its vapour density show the composition of the 

 liquid to be represented by the formula Fe(CO).„ and Messrs. 

 Mond and Langer have therefore called the compound ferro- 

 penta-carbonyl. 



If exposed to light in a sealed vessel for several hours, it 

 deposits gold-coloured tabular crystals having a metallic lustre 



NO. I I 79, VOL. 46] 



like gold when dry, but becoming brown by gradual decomposi- 

 tion when exposed to air. These crystals appear to contain a 

 slightly smaller amount of carbonic oxide than the liquid com- 

 pound from which they are deposited. Mr. Mond and his co- 

 laborateurs are still actively engaged in pursuing the researches 

 which have brought to light the formation of these remarkable 

 metallic compounds, whose discovery and properties suggest pos- 

 sitiiliiies in several directions of ttchnical chemistry which will 

 doubtless lead to interesting inveslig itions. 



The first report made by Prof Roberts-Austen to the Alloys 

 Research Committee of the Institution of Mechanical Engineers, 

 bearing upon the particular investigation undertaken by him at 

 their request, although little more than introductory in its 

 character, is full of interest, and of importance not only on 

 account of the valuable information it furnishes regarding the 

 method of investigation adopted by him and of the preliminary 

 results attained by its agency, but also because of the interesting 

 discussion elicited by its presentation to the Institution of 

 Mechanical Ent:ineers at their meeting last autumn. 



At our annual gathering a year ago we had the advantage of 

 receiving from Prof. Roberts- Austen a description of the auto- 

 graphic method ad >pted by him for recording the results in- 

 dicated by the Le Chatelier pyrometer, the eflicient operation 

 of which I had an opportunity of witnessing as a mem er of the 

 Alloys Research Committee. We also heard from Sir Lowthian 

 Bell that he had already successfully and very usefully applied 

 this pyrometer to determine the temperature of the blast enter- 

 ing a furnace at a considerable distance from the point of obser- 

 vation. We shall, I trust, have the advantage of learning the 

 results of further experience by Sir Lowthian and others in the 

 practical application of this much-needed ins'rument in con- 

 junction with the automatic recording system used by Prof. 

 Roberts- Austen ; the observations made by the present President 

 of the Institution of Mechanical Engineers, by Mr. Henry M. 

 Howe, of Boston, and by others at the discussion of the 

 Professor's report, demonstrated that several valuable appli- 

 cations were already being made of the Le Chatelier pyromeier 

 and the system of continuous record of its indications. While 

 it is satisfactory to uie, as one of the earliest to use the ingenious 

 pyrometer designed by my distinguished friend the late Sir 

 William Siemens, to note that its trustworthiness as an indicator 

 of temperatures up to 500° C. has been vindicate! by the work 

 of Messrs. Callendar and Smith, the accuracy and shirpnes- of 

 the indications of Le Chatelier's jiyrometer, the simpliiity of its 

 character, and the well established trustworthiness of its results 

 at temperatures of over 1000° C, render it decidedly more 

 valuable to the practical metallurgist, as well as to the scientific 

 investigator, than any instrument of the class hitherto available. 

 We shall none the less be glad to hear what Mr. Callendar has* 

 to tell us on the present occasion with regard to the results of his 

 persevering and, I believe, successful labours in discovering and 

 eliminating the delects of construction which served to destroy 

 the confidence placed, in the first instance, on the indications 

 afforded by platinum pyrometers. 



The tendency of the discussion following the reading of Prof 

 Roberts Austen's report, which was shared in by Mr. Robert 

 Hadfield, Mr. Henry M. Howe, and by some others whose rij;ht 

 to criticism was beyond di-^pule, was to emphasise the necessity 

 for caution in the application of theoretical views, regarding the 

 laws which regulate the mechanical or physical properties of 

 metals, to predictions as to the influence upon the properties of 

 metals, such as iron, of particular impurities. I believe no one 

 will be disposed to differ from the view expressed on that 

 occasion by Prof. Arnold, that, for a thoroughly comprehensive 

 examination into " the effects of small admixtures of certain 

 elements on the mechanical and physical properties of iron, 

 copper, lead, and other metals," it is indispensable to combine 

 different lines of investigation with the 1 articular one which 

 Prof Roberts Austen has so far prosecuted with very promising 

 results. 



The fame which Mr. Gruson has acquired in connection with 

 the production of chilled iron structures, for land defence, }>re- 

 senting marvellous powers of resistance, must cause memhers of 

 the Institute to look forward with much interest to the commu- 

 nication which has been promised us by the director of the 

 Gruson Works, Mr. E. Reimers, on the manufacture and appli- 

 cation of chilled cast iron, a .subject with which, cspeciall) in 

 regard to the selection of varieties and mixtures of iron suitable 

 for securing a structure of mttal essential to the attainment 'f 

 combined toughness andhirdness in armour-piercing projectiles. 



