February io, 191 6] 



NATURE 



659 



manufacture of the rheostats, they hope to retain and 

 exteiid the markets opened to them by the temporary 

 jjaralysis of German export trade. Messrs. Isenthal 

 also inform us that they find "by careful organisation, 

 by manufacturing the component parts of these rheo- 

 stats in very large quantifies, i.e. practically making 

 the whole rheostat except the winding in very large 

 quantities," the instruments do lend themselves to 

 mass production. Before the war they did not con- 

 sider themselves justified in incurring the expense and 

 work required for such methods of manufacture, and 

 therefore purchased the apparatus from abroad. But 

 they add: — "The closing of our relations with the 

 central Continent has given just that impetus which 

 was needed for us to set aside ordinary commercial 

 considerations, hence our present facilities for manu- 

 facturing this apparatus." 



Furnace Spectra of Cobalt and Nickel. — ^To the 

 metals (Fe, Ti, V, and Cr) whereof the electric furnace 

 spectra have already been investigated in such pains- 

 taking and accurate manner by Dr. King, must now 

 be added Co and Ni {Astrophysical Journal, vol. xlii.. 

 No 4). Fourteen pages are given up to tabular matter 

 similar to that for the elements previously studied. 

 -' Attention may be directed to some results of an un- 

 expected character; thus not only is the violet end 

 found relatively rich in lines, but all the enhanced 

 lines of cobalt (except only AA 3878-90 and 3904-23) in 

 the region of shorter wave-lengths than A 4077-56 have 

 been classified as furnace lines. Another peculiarity 

 is the fact that each of the classes I., II., and III. 

 contain some lines that attain a maximum in the 

 furnace and are weaker in the arc, thus affording, as 

 regards the lines of Class III. A, a group of; lines 

 special, perhaps, to a range of temperature of some 

 500° C. — a feature worthy of further attention. 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences. — Mars, now nearly as 

 bright as Sirius, will be in opposition early on Friday. 

 Jupiter and Venus, so conspicuous in the western 

 twilig'ht, reach conjunction about 3 a.m. on February 

 14. Their nearest approacli takes place earlier, about 

 midnight, Venus being 26' S. Even at 7.30 p.m., 

 February 13, they will be only 32' apart. The moon 

 occults a 3-2 mag. star, e Geminorum, on February 14. 

 As seen from Greenwich disappearance occurs at 

 iih. 3m. The moon is in conjunction with Neptune 

 on the evening of February 16 at 6h. 24m. Geo- 

 centrically the planet will be 1° 2' S. Comet 1915c 

 (Taylor) can still be glimpsed with a 3-in., but is not 

 a suitable object for such a small aperture. The fol- 

 lowing positions are from a continuation of the Copen- 

 hagen ephemeris for Greenwich midnight : — 



h. in. s. ^ ^ 



Feb. II ... 5 30 22 ... +24 21-3 

 15 ••• 36 45 •-• 25 39-0 



19 ... 43 48 ... 26 508 



Shifts of VVave-lengthp.— Modern measurement of 

 wave-lengths, in striving successfully after an accurate 

 third decimal figure, has begun to detect all kinds of 

 causes that result in wave-length alterations. In 

 solai- spectroscopy, in addition to the well-known 

 pressure and motion effects, the recondite theory of 

 relativity and the ubiquitous anomalous dispersion 

 rhampioned by Freundlich and Julius respectively have 

 afforded explanations of the observed displacements. 

 In the one case it is an intense gravitational field 

 that is adduced as competent ; in the other the mutual 

 ' Ifect of neighbouring lines. In the laboratory length 

 nf arc, its internal pressure, distance from pole, im- 

 purities, change of electrical conditions, have been 

 described as the source of displacement bv Royds, 

 Albrecht, St. John, Burns, and Bilham. The latter, 

 working in Prof. Fowler's laboratory at South Ken- 

 sington, has now studied the special case where the 

 adventitious element itself gives rise to strong lines 

 {.istrophysical Journal, December, 1915). A number 

 of iron lines in the regions of H and K were measured 

 in the spectrum given by a carbon arc fed with Fe 

 filings, and also when the arc was fed with a mixture 

 of filinpfs and calcium chloride, the calcium lines being 

 measured in both cases. The results obtained in this 

 very interesting research indicate that some lines are 

 susceptible, wiulst others have constant wave-leng^ths. 

 The K line of calcium is found to differ by 0-008 A. in 

 the two sources. One hesitates to think of the array 

 of conditions it will become necessary to introduce 

 into the specification of standard lines. 

 NO. 2415, VOL. 96] 



THE ELECTRO-THERMIC SMELTING 

 OF IRON ORES. 



'X'HE rapid growth of the application of the electric 

 ■»■ furnace to the metallurgy of iron and steel is 

 certainly the most noteworthy feature of the develop- 

 ment of this industry during the last decade. Ten 

 years ago "electric steel" was largely a novelty. To- 

 day there is scarcely a branch of this highly diversified 

 and complex industry in which electrothermic heating, 

 has failed to secure a footing and to justify itself. 

 This progress is all the more remarkable when it is 

 remembered that the steel manufacturing industry 

 "owing to its age and importance, and also to the 

 capital invested in it, is one of the most conservative 

 and settled of all industries." * 



The earliest uses to which electric furnaces were 

 applied were to the production of (i) ferro-alloys, con- 

 taining iron, carbon, and such elements as tungsten, 

 molybdenum, vanadium, etc., which indeed cannot be 

 made in fuel-fired furnaces ; and (2) of the highest 

 classes of carbon and alloy tool steels, where they com- 

 peted successfully with crucible furnace products. 

 Having " made good " up to this point, they were next 

 developed, not in direct competition with Bessemer 

 and open-hearth furnaces, but as important adjuncts to 

 them, and within the last seven years a great variety 

 of products — e.g.. gun, tyre, and axle steel, wire ani 

 plate billets, and rail and girder steel — are manufac- 

 tured with their aid. Such processes may be classed 

 as electrothermic refining, for they take the metal as 

 delivered by the Bessemer or open-hearth furnace, and, 

 owing to their high temperature and more neutral 

 atmosphere, permit the formation of refractory basic 

 and even reducing slags, e.g., calcium carbide, which 

 carry the refining of the steel to a further stage, and 

 produce a purer and more trustworthy metal. Espe- 

 cially has this been the case with the manufacture 

 of rail steel in Germany and America, where it has 

 been found that the trustworthiness of the steel is so 

 much increased by electrothermic refining that the 

 railway companies are willing to pay considerably 

 more for rails produced in this way. Mention must 

 also be made of the application of the electric furnace 

 to the production of mild steel castings — always a diffi- 

 cult operation — where a very fluid metal can be ob- 

 tained, and a better separation of gaseous and other 

 impurities. Heroult ' recently quoted instances in 

 which it had been fouikL to be unnecessary to anneal 

 such materials at all, since their properties were fully 

 as good as those of the best rolled mild steel made in 



1 " Electrothtrmal Methods of Iron and Steel Production." By J. B. C. 

 Kershaw, p. 3. 



- Trantaclions of the Eifchth Intemalional Congress of Applied 

 Chemistry. New York. September, 1912. 



