30 



NATURE 



[March 14, 19 18 



utilisation of the waste bark of the wattle-tree, which 

 is extensively cultivated in South and East Africa. 

 The waste, from which the tanning constituent has 

 been removed, can be utilised both here and in Natal, 

 where tanning extract is at present being produced, 

 for the manufacture of an excellent brown paper or 

 millboard. The waste from tanyards in this country 

 may thus be a source of remuneration, and in South 

 Africa an important industry may be created where 

 brown paper and millboard for packing purposes, 

 especially for fresh fruit transport, are in great demand, 

 and have to be im|X)rted for the purpose. The wood of 

 the Acacia trees fram which (the bark has been taken 

 can also be utilised for millboard. According to the re- 

 port, arrangements are already being made for the use 

 of spent wattle bark in this country by paper manu- 

 facturers. 



A PAPER entitled " British Trade and the Metric 

 System " was read by Mr. E. A. W. Phillips at a 

 recent meeting of the Concrete Institute. Mr. 

 Phillips proposes a system of weights and measures 

 including, in addition to the more usual English de- 

 nominations, a decimal scale based on a " British 

 metre " of 39-6 in., the ton of 2240 lb., divided into 

 ten sacks, or 1000 "British kilograms," and a cubic 

 British metre of pure water divided into 1000 litres. 

 It is mentioned that the proposed metre is the same 

 length as the ancient Belgic yard, which the author 

 calls the "Anglo-Saxon metre," and he states that 

 this has existed in Britain since the third century at 

 least. Five of these yards made the rod, pole, or 

 perch used in land measure. Mr. Phillips raises the 

 question of the possibility of making his proposed 

 decimal system the international standard for trade, 

 commerce, and engineering, and of restricting the 

 metric system proper to purposes of pure science. As 

 regards coinage, his proposals include the retention 

 of the pound sterling of ten florins and the division of 

 the florin into 100 imaginary cents of account, not 

 coined, for use in decimal accounting and decimal 

 quoting. 



A RECENT Technologic Paper (No. 103) of the U.S. 

 Bureau of Standards deals with some typical cases of 

 selective corrosion of 60 : 40 brass, or Muntz metal. 

 The specimens described by the author, Mr. H. S. 

 Rawdon, include bolts, sheathing, and condenser 

 tubes. In all the cases examined, the selective corro- 

 sion takes the form of a removal of zinc from the 

 ,/3 crystals, the a constituent not being attacked untU 

 a later stage. The corroded mass retains its external 

 form, but consists only of spongy copper. A sharply 

 defined boundary between the corroded portion and un- 

 altered brass is always present, without any inter- 

 vening zone of lower zinc content. Chemical action 

 advances in the first instance along the boundaries of 

 the crystal grains, and in the ^8 crystals also along 

 systems of intersecting planes, which may be twinning 

 planes. Contact with a more strongly electro-negative 

 metal has -an accelerating influence, but none of the 

 actual cases observed can be attributed to this cause. 

 Experiments with grooved bars under tensile stress 

 show that local increase of stress favours corrosion. 

 Annealing has little effect. The results on the whole 

 confirm those obtained by previous workers, but the 

 photomicrographs illustrate very clearly the successive 

 stages in the removal of zinc from alloys of this class. 



There has been such a vast increase in the manu- 

 facture of organic nitro-compounds for the produc- 

 tion of both dyes and explosives since the outbreak 

 of war that the vexed question of the estimation of 

 nitrogen therein has probably become acute. To the 

 ! Journal of the Society of Chemical Industry of August 

 H NO. 2524, VOL. lOl] 



31 last Mr. A. P. Sachs contributes an account of 

 what seems to be a highly successful method of effect- 

 ing this estimation. The method depending on the 

 reduction of the nitro-group with stannous chloride 

 solution in an open flask and estimation of the excess 

 of reducing agent with iodine was found to be un- 

 satisfactory in the case of nitrated " solvent naphthas." 

 The author finds, however, that if the nitrq-compound 

 is heated in a sealed tube with excess of stannous 

 chloride solution (prepared by dissolving the dihydrated 

 salt in twice its weight of 25 per cent, hydrochloric 

 acid) at 120° for two hours, the tube being shaken 

 every fifteen minutes, reduction is complete. The ex- 

 cess of stannous chloride is then determined by titration 

 with decinormal iodine solution, using starch as indi- 

 cator. It is of importance that exactly the same 

 volume of stannous chloride solution should be used in 

 all experiments and for the blank determination. 

 Quoted analyses made by this method and by the com- 

 bustion method on the same substances gave very con- 

 cordant results. 



Among forthcoming books of science we notice the 

 following: — "The Future of Our Agriculture," H. W. 

 Wolff (P. S. King and Son, Ltd.); "Dragons and 

 Rain Gods, etc.," Prof. G. Elliot Smith (Manchester 

 University Press); " Bibliography of the Geology and 

 Eruptive Phenomena of the more Important Volcanoes 

 of Southern Italy," the late Dr. H. J. Johnston-Lavis ; 

 "An Economic Geography of the British Emipire," 

 C. B. Thurston; "The New Regional Geographies, 

 vol. iii., Europe and Africa," L. Brooks, and a new 

 edition of "The Application of Hyperbolic Functions 

 to Electrical Engineering Problems," A. E. Kennelly 

 (University of London Press, Ltd.); "Problems of Re- 

 construction," papers read at the summer meeting held 

 at the Hampstead Garden Suburb, August 3-17, 1917, 

 with an introduction by the Marquess of Crewe; 

 " Forestrv Work," W. H. Whellans (T. Fisher Unwin, 

 Ltd.); "The Year Book of Wireless Telegraphy and 

 Telephony, including Map of the World showing Wire- 

 less Telegraph Stations, 1918" (The Wireless Press, 

 Ltd.). 



OUR ASTRONOMICAL COLUMN. 



The New Wolf Planet. — An orbit of this body 

 (which has been designated DB) has now been com- 

 puted by Mr. G. Stracke, and its accuracy is confirmed 

 by a recent Greenwich photograph : — 



Perihelion passage 1918 January 3-617, G.M.T. 



CO 347° 46' I5"-| 



9, "o 54 I V19180 



z 8 57 41 J 



32 12 5 



Period 4*025 years 



Perihelion distance n82 



Aphelion ,, 3*879 



The perihelion distance is very little greater than 

 that of Eros, but the period and eccentricity are much 

 larger. In some revolutions the planet will suffer con- 

 siderable perturbations by Jupiter, but there will be no 

 near approach in the coming revolution. The fact that 

 the period is very close to four years implies that there 

 will be another near approach to the earth at the next 

 return, of which possibly advantage might be taken 

 to make a determination of the solar parallax. The 

 planet, however, is a little too faint for this purpose, 

 being only of the tenth magnitude in the most 

 favourable circumstances. Its diameter can scarcely 

 be more than four miles. 



The orbit is of much the same type as that of Albert, 

 discovered in 191 1, but never seen since that year. 

 The present body has been much better observed than 



