October 6, 1910] 



NATURE 



441 



had been deposited in regular layers, which differ in 

 colour and composition ; the same succession is repeated 

 time after time, with layers of varying thickness. He 

 early suspected that each cycle in this series might repre- 

 sent one year's deposition, the layers laid down in the 

 summer being thicker, as the floods then carried most 

 mineral matter to the sea, and being brown owing to 

 oxidisation, the autunmal layers being thinner and also 

 blacker, owing to the higher percentage of organic matter. 

 Near Stockholm there are many small linear moraines, 

 each ■ line of which he thought might be the terminal 

 moraine deposited in one year. After thirty years' work 

 he has discovered, b_\' the correlation of the evidence of 

 the seasonally banded clays, of the northward advance of 

 tlieir successive layers as they followed the receding ice 

 front, of the annual moraines, and of the annual delta 

 deposits laid down at the mouths of glacial rivers, that the 

 retreat of the ice from Scandinavia was more rapid and 

 less ancient than had been thought. The ice covered the 

 site of Stockholm only a few thousand years ago, and 

 withdrew at the rate of 200 metres a year. The latter 

 part of the lecture was abridged, but Prof, de Geer 

 announced that at Ragunda he had found a section which 

 showed the full sequence of clays, from a layer formed 

 in 1796, through a succession of lake clays and a fjord 

 clay, to the seasonally banded clays deposited along the 

 front of the receding ice-sheet ; and, according to his 

 determination, the ice receded from Ragunda only 7000 

 years ago. Prof, de Geer concluded his lecture with 

 expressions of hope that the application of his method 

 would allow of positive proof whether the glaciations of 

 Scandinavia, the British Isles, and North America were 

 synchronous. 



Prof. Van Ilise then delivered a lecture on " The In- 

 fluence of .\pplied Geology and the Mining Industry upon 

 the Economic Development of the World." He confined 

 his lecture to the conservation of natural resources, and 

 considered mainly the cases of iron and coal, as the 

 failure of other metals would involve only minor readjust- 

 ments. The working of coal and iron on a large scale 

 introduced the industrial revolution of the nineteenth 

 century, and gave commercial supremacy to countries 

 endowed with both minerals. A civilisation can exist 

 without iron ; but a man with a wooden plough could 

 till only one-tenth as much as with an iron plough, and 

 hence the exhaustion of iron would mean that countries 

 would support much smaller populations. The supply of 

 high-grade iron ores will not last long in the chief iron- 

 producing countries, but the quantities of low-grade ores 

 are so immense that the total failure of iron ores is 

 practically out of the question. Moreover, much of the 

 iron extracted is available for all time. The coal ques- 

 tion is more serious, as fuel when burnt is gone for ever, 

 and the supply is so limited that it cannot last indefinitely. 

 At the present rates of consumption, the coal in Britain 

 and Germany may last from 500 to 1000 years, and the 

 United States has sufficient for 6000 years ; but if the 

 consumption continues to increase at its recent rate all 

 (he coal in seams that can be worked under existing con- 

 ditions will be used in 150 years; within 100 years rising 

 prices will force men to turn to other sources of power — 

 natural gas, petroleum, tides, and the sea; these, though 

 all possible sources of power, are too expensive. The only 

 perennial source of cheap power is water. The industrial 

 future lies with countries rich in iron ores and water- 

 power. Scandinavia has both, and it is especially 

 favoured, as its recent glaciation has left so many lake 

 basins, which provide easy water storage and the uniform 

 discharge most suitable for the production of power. 



Prof, van Hise made an earnest appeal to men of 

 science to ask how long our natural resources can last, 

 and to protest against needless waste. Primitive man and 

 anv philosopher at the beginning of the nineteenth century 

 would have felt confident that natural resources would 

 last indefinitely. But it is now manifest that new prin- 

 ciples must apply to the conservation of our mineral 

 supplies, and it is our manifest duty to leave our 

 descendants a fair sharj, so that they may enjoy the 

 comfort and leisure necessary for the intellectual develop- 

 ment bv which they can attain the godlike destiny of 

 man. 



Iron Ore Supplies. 



The question of the iron ore supplies of the world was 



subsequently considered in a conference opened by the 



Prime Minister of Sweden, M. Lindman, who declared 



the conservation of iron ores to be more necessary than 



I of coal, as water supply offers a permanent source of 



power and heat. He stated the measures adopted by 



I Sweden to limit the export of its high-grade ores ; they 



I appear to amount to the future nationalisation of the chief 



I iron mines. 



[ Prof. Sjogren regarded the iron ore reserves as practic- 

 ally inexhaustible, and he added some fresh data to those 

 announced in the report on the iron ore reserves of the 

 world. Estimates received from Mr. Inouye. of Japan, 

 I show that the reports as to the unlimited iron ores in 

 I China are without adequate foundation. According to 

 I Prof. Sjogren, the best idea as to the amount of ore avail- 

 j able in the less known regions of the world can be learnt 

 j by multiplying the area by a factor obtained by dividing 

 the ore reserves, actual and potential, of Europe, the 

 United States, and Japan, by their total area. On that 

 j assumption the ore supply available is 425,000 million 

 j tons. 



Prof. Beyschlag defended the estimates of German ore 



I supplies prepared for the congress from some recent 



I criticisms, and proposed a commission to secure official 



I evidence as to the ore reserves of the United States and 



the chief iron-producing countries. 



M. de Launay, on the other hand, issued a warning 

 against a serious possible source of loss, which is often 

 disregarded bv the advocates of conservation. There are 

 in Europe vast quantities of low-grade ores, distant from 

 supplies of fuel or power, that could not be worked in 

 competition with the high-grade ores of many countries 

 not yet iron-producing. If the European low-grade ores 

 are not used now, in fifty years' time they will probably 

 be useless. M. de Launay claimed, therefore, that under 

 such conditions the sound policy is to accelerate by all 

 means the production of these ores. 



Prof. J. F. Kemp also repudiated the fears of an iron 

 famine. He predicted a diminished demand on iron ores, 

 as we are now passing from the age of steel to the age 

 of cement, and also further discoveries of ores, such as 

 that in Cuba, which will probably lead to the establish- 

 ment of large iron works on the .Atlantic coast of America. 

 He insisted that the critical point with iron is not the 

 supply of ore, but the exhaustion of the coking coals. 

 Even if all the heat be supplied by electricity, half a ton 

 of coking coal will still be required for the reduction of 

 a ton of ore. 



The only speaker in the discussion. Prof. J. \V. 

 Richards, of Lehigh, also agreed that the danger is with 

 the coking coal, and he suggested a commission on the 

 supplies of this material. 



Glacial Erosion. 



The first sectional discussion was on glacial erosion, 

 under the chairmanshio of M. de Margerie. Papers were 

 contributed bv Profs. Hogbom, Penck. Davis and Reusch, 

 and Dr. Nordenskiold. and in the discussion speeches were 

 made bv Profs. Wahnschaffe, Baltzer, Heim and Salomon, 

 Dr. G.' F. Becker, and Dr. Sederholm. Prof. Penck, in 

 an eloquent summary of his paper, explained the evidence 

 which has led him to attribute the main work in the 

 formation of .Mpine valleys to the action of ice. Prof. 

 Davis insisted on the importance of the physiographic 

 studv of the question, and the comparison of never 

 glaciated mountains, taken as the " norm " of mountain 

 iform, with those that have been glaciated : he advocated 

 the formation of ciraues by the " plucking " away of the 

 rocks at the head of a valley, until the whole mpuntain 

 ridge at the head of the valley may be torn away. Prof. 

 Hogbom. while advocating the erosive power of ice, 

 remarked the difficultv of explaining some Swedish vallevs 

 that had been filled with ice. which had not removed their 

 soft, pre-glacial deposits. Prof. Wahnschaffe referred to 

 cases where ice had covered soft deposits, and had not 

 ev»n shifted boulders Iving on them. 



Prof. Reusch described the glaciated valleys near 

 Christiania, which he thought were pre-glacial, and con- 



NO. 2136, VOL. 84] 



