i;^ 



NATURE 



[October 14, 19 15 



Germany purchased abnormally from Russia during 

 the first seven months of 19 14 the fact would probably 

 have been reflected in an increase in the price of man- 

 ganese-ore during- the year. As a matter of fact, the 

 price per unit of manganese-ore fell steadily from a 

 maximum of 12 to 12^ pence in January, 1913, to 9^ 

 to 9^ pence in July, 1914. 



From what precedes it seems justifiable to conclude 

 (a) that on the outbreak of war the Teutonic Powers 

 had no great accumulated stocks of manganese-ore, 

 perhaps a maximum of 200,000 tons ; (b) that, assum- 

 ing war conditions necessitate a maintenance of the 

 iron and steel industries of those two countries at a 

 peace standard, about 600,000 tons of ore a year must 

 be obtained from fresh sources to replace imports in 

 time of peace ; (c) allowing that the Teutonic Powers 

 might succeed in increasing their internal production 

 by 100,000 tons and obtain 50,000 tons of manganese- 

 ore from Turkey, if the Allied fleets could prevent all 

 manganese-ore from outside from reaching Germany 

 and Austria these countries would be faced with a 

 shortage of 250,000 tons of manganese-ore in the first 

 year of war, and with a shortage of 450,000 tons per 

 year afterwards, increased to 500,000 tons per annum 

 once the Dardanelles are forced. 



The Germans will doubtless find means of dispensing 

 with the use of manganese-ore as much as possible, 

 and they may devise methods of utilising the man- 

 ganese silicate, rhodonite, of which they appear to 

 possess a considerable quantity ; but it seems inevitable 

 that the shortage of manganese-ore, once it is felt, will 

 hamper seriously the German iron and steel industries. 



It appears therefore to be of the utmost importance 

 that every efl'ort should be made by the Allied fleets to 

 prevent smuggling of manganese-ore (or ferro-man- 

 ganese and spiegeleisen) into Germany and Austria, 

 either direct or through neutral ports". It is to be 

 noted that of the small countries adjoining the enemy 

 countries the only one manufacturing iron and steel is 

 Sweden, which does not show either manganese-ore, 

 ferro-manganese, or spiegeleisen, amongst her imports 

 In normal years. L. Leigh Fermor. 



Calcutta, September 2. 



Jupiter's Two Principal Markings. 



At Intervals during the work of a comparison of 

 stellar magnitudes, the 26-In. reflector has been turned 

 on Jupiter, in order to determine the present rotation 

 period of the various surface currents, and It is hoped 

 that results of some value wjll be obtained by the end 

 of the present apparition. The following longitudes, 

 based on transit estimates, of the two most Important 

 objects on Jupiter, viz., the S. Tropical Disturbance 

 and the Red Spot Hollow, have been determined :— 



length at the S. equatorial belt, and in point of size 

 forms a wonderful object when centrally on the meri- 

 dian. Its length Is such as to extend nearly from 

 limb to limb. It first appeared as a comparatively 

 small object in the spring of 190 1, and although in 

 the meantime It has fluctuated in size considerably, 

 It exhibits no signs of decadence. 



When the air is steady, the Red Spot can be seen 

 without difficulty in the 26-In. reflector. It Is, how- 



NO. 2398, VOL. 96] 



ever, well to state that it is now no more distinct than 

 It has been for many years. Displaced towards the 

 f. side of the Hollow, its following end coincides ji 

 almost with the longitude of the f . shoulder of the i 

 Hollow, while Its northern contour is nearly in line 'I 

 with the S. edge of the S. equatorial belt. It will be ; 

 seen from the above longitudes that the length of the j 

 Hollow Is roughly 38°, a similar dimension having 

 obtained during the last fifteen years. 



October 2. Scriven Bolton. 



The Orionid Meteoric Shower. 



The ensuing return of these meteors will deserve, 

 and probably will repay, observation. The moon will 

 be full on October 23, and will somewhat interfert 

 with the display, but It is rather a long-continued one. 

 and may be favourably witnessed in the morning- 

 from about October 17-21 before sunrise. 



From a great many observations made at Bristol, 

 and which I have recently discussed, I believe that, 

 the shower extends from the first week In October to 

 the first week in November. I have determined two 

 radiants, as follows, from my collected materials from j 

 1873 to the present time : — \ 



October. 3-12— 91 i° + 14^°; 10 meteors. j 



October 25-November 7 — 92^°+ 14°; 18 meteors. . 



For the intervening period between October 12 and 25 | 

 I have a number of radiants of this well-known and : 

 annually recurring shower. The two radiants given ; 

 above are adequately supported by a sufficiency of , 

 streaking meteors, and I believe represent genuine] 

 positions, but it cannot absolutely be proved that they j 

 are based on the flight of true Orionlds. Remember- "^ 

 ing, however, that the radiation Is from a fixed point 1 

 at about 92° 4- 15° for certainly a fortnight near the ^ 

 maximum, I believe I am justified in ascribing aj 

 month's activity to the shower. It would be serving ; 

 a useful purpose If observers watched the display veryj: 

 carefully this year, and ascertained the place of the\ 

 radiant point accurately between, say, October 15 andj 

 25. The fact of this stationary radiant would then be: 

 no longer open to criticism. W. F. Denning, ■ 



44 Egerton Road, Bristol, October 8. 



Visibility of Distant Objects in Warfare. 



I WAS much interested in the article on "Visibility.; 

 of Distant Objects In Warfare " In Nature of Septem- 

 ber 30. The question is of vital importance to many ; 

 who, like myself, spend much of our time in artillery | 

 observing stations. •; 



I believe a good deal of misconception exists as toj 

 the reasons why the Germans use various-coloureds 

 sandbags. It may be that their use is intended to| 

 make for invisibility, but I am inclined to think that-! 

 it is primarily due to their lack of materials for making^ 

 sandbags. They lack jute, and are consequently forced^ 

 to make use of the stocks of various-coloured dress^ 

 materials, In some cases indeed using the uniforms-^ 

 they have taken from the bodies of any men who rnay I 

 have been killed near their trenches. It is interesting ; 

 to note that the colour most commonly employed in 

 making their latest sandbags is a pinky-red. % 



In dealing with the question of visibility, It seems ■ 

 to me that the whole tendency in designing uniforms] 

 and in" making fortifications is to Ignore the important ij 

 consideration of shadow, which Thayer has shown to ^ 

 have such an Important bearing on the coloration of \ 

 animals. 



I have hopes that your article may Induce some man \ 

 of science to take the matter up, and perhaps submit^ 

 his conclusions confidentially to Lord Fisher's Com- i 

 mission. Artillery Observing Officer. . 



October 6. -\ 



