/O 



NATURE 



[March 20, iqi 



and Mr. G. Smeal (Government research scholar), 

 dealt with temperatures near the freezing point, and 

 the second, by Mr. Smeal, dealt with temperatures 

 up to 3 1 -4° C. The discussions appear to have proved 

 that the suggested coefficient, being so nearly unity, 

 is not wanted, especially if the covering be thin muslin 

 and be kept clean. The factor, A = 0-00072, derived 

 from the observations and careful computations, varies 

 slightly according to wind force. In the event of any 

 modification of the simple formula being accepted it 

 might be in this sense, but we suggest that it would 

 be more to the point if one formula were selected 

 from among those which already exist, and be recom- 

 mended for general adoption. 



A useful paper on the wet-bulb thermometer and 

 tropical colonisation, by Prof. J. W. Gregory, F.R.S., 

 is published in the Journal of the Scottish Meteoro- 

 logical Society (vol. xvi., No. xxix.). The author 

 points out that the view that the tropics are injurious 

 to health is prevalent, but the explanations why this 

 is so are very unsatisfactory. Heat is mostlv re- 

 garded as one of the principal factors of tropical 

 maladies, but it is now recognised that no locality 

 with a dry climate has a temperature so high as to be 

 injurious to health; in fact, the hottest districts in a 

 country are often the healthiest. Healthiness of 

 tropical localities does not depend upon diurnal or 

 annual range of temperature, and moisture is not 

 necessarily injurious; the latter is better for some 

 constitutions, but heat and moisture combined may 

 be very harmful. Experiments appear to indicate that 

 "the industrial development of any locality where the 

 wet-bulb temperature commonly exceeds '8o° will be 

 almost, and if it exceed 88°, quite impossible." But 

 statistics supplied to the author by the Meteorological 

 Office show that such high wet-bulb temperatures do 

 occur in well-populated tropical localities. The author 

 laments that the distribution of such temperatures is 

 not well known, and refers to the collection of ob- 

 servations in Australia by Prof. W. A. Osborne, of 

 Melbourne. The annual summary of the Australian 

 Monthly Weather Report for 1910 (received by us in 

 July, IQ12) contains monthly wet-bulb isotherms from 

 oh. a.m. observations, with means of 8o° in the north- 

 west in December- February inclusive. 



RECENT ADVANCES IN SCIENTIFIC 

 STEEL METALLURGY.* 

 TT has already been pointed out that the year 1870 

 marked the commencement of the tungsten era, 

 and 1880 that of the tungsten-chrome era. But the years 

 1899 to 1902 inaugurated what is destined to be the 

 most remarkable epoch of the three, namely the vana- 

 dium era. During these years was carried out in the 

 experimental steel works of Sheffield University a 

 series of researches on the influence of the compara- 

 tively rare metal vanadium on plain carbon steel and 

 on alloy steels. At that time (1899) vanadium was 

 60s. per lb. In 1912, owing to the large demand, the 

 cost had fallen to 10s. per lb. 



The first report, having reference mainly to cutting 

 steels, was issued in June, 1900, and the" second and 

 third reports respectively in January and June, 1902. 

 The results are briefly summarised in the two next 

 paragraphs. 



June 28, 1900. 



"The results of this preliminary investigation have 

 profoundly impressed upon my mind the future before 

 vanadium as a steel-making element, and even at this 

 early stage of my knowledge of its effect, I venture 



1 Discourse delivered before the Rnyal Institution on Fridav January 

 24, by Prof. J. O. Arnold, F.R.S. Continued from p. 4™ ' ' ' "" 



NO. 2264, v OL. 91] 



to say that its action resembles that of tungsten, but 

 that it is from ten to twenty times as powerful as the 

 latter element." 



January 14, 1902. 



" It is already evident that as a steel-making element 

 vanadium will place in the hands of metallurgists and 



(«) Carbon, o'6o per cent. Vanadium, 0-71 per cent. Pale ground mass of 

 slightly vanadiferous ferrite. Dark areas, troostitic vanadium pearlite. 

 Less dark^areas, sorbitic vanadium pearl te. While cell walls and 

 ron cementite, resulting from thermal decomposition of 

 pearlite, a lew areas of which still remain undecomposed. 



laminated 



(6) Carbon, 0-93 per cent. Vanadium 5-84 per cent. Ground massof sorbitic 

 vanadium pearlite, overlaid with a broken and irregular mesh-work of 

 vanadiferous ferrite. 



Flu. 6. — Magnified 450 diameters. 



engineers a very powerful weapon, because it is now- 

 demonstrated beyond doubt that the addition of a few 

 tenths per cent, of vanadium raises the elastic limit 

 of mild structural steel at least 50 per cent., without 

 seriously impairing its ductility or presenting any 

 difficulty in the hot or cold working of the steel." 



