430 



KNOWLEDGE. 



November, 1913. 



in detail, and with the extent, position, and importance of 

 supplies of metalliferous minerals. But a matter which is both 

 fundamental and more definite is the supply of food. 



Agriculture has presented to the man of limited capital who 

 has energy and ambition and the desire to be his own master 

 in a new country the most attractive if not the only prospect. 

 The principles underlying his work are these : manual labour, 

 which is scarce and costly, is the minimum ; the crop covers 

 a large area, so as to pay in spite of the low yield per acre ; 

 the ground opened up in the first year is sown and the three 

 months which elapse before the crop comes to the harvest are 

 occupied entirely in opening up fresh land for the next spring. 

 We find Canadian and United States harvests give as low as 

 twelve to fourteen bushels of wheat per acre, Australian (and 

 Russian) eight to ten, compared with twenty-eight to thirty-two, 

 twenty-seven to thirty-three, thirty to thirty-five for the United 

 Kingdom, Holland, and Belgium respectively (J. F. Unstead, 

 "The Statistical Study of Wheat," Geographical Journal, 

 August, September, 1913.) 



As the demand for wheat grows, the supply may be 

 increased, either by increasing the amount of land under 

 cultivation or by increasing the yield. In certain parts the 

 amount of suitable land under cultivation has closely 

 approached the limit of the amount available, and in any case 

 there is a very definite and reasonably well-ascertained 

 maximum of such land. In the United States this is already 

 evident in its effects. (The American Transcontinental 

 Excursion, 1912, I, " Economic Aspects," by G. G. Chisholm, 

 Geographical Journal, October, 1913.) Intensive cultiva- 

 tion is being more and more widely practised, and from the 

 Western States there is a steady stream of emigration to 

 Canada, where the amount of unoccupied wheat land is 

 greater. 



It is on account of the great and rapid development of the 

 means of sea and land transport that certain less crowded 

 regions have been able to act as granaries for the thickly 

 populated industrial areas, and this has led to a type of 

 modern colonisation of a markedly recent and rapid growth. 

 But the countries originally mainly agricultural are filling up 

 with an industrial population as new resources are explored 

 and opened up. The consequence is that home productions 

 are more and more used at home, and the surplus for export 

 diminishes. The mean percentage of the total production 

 of wheat exported from the United States fell from thirty- 

 two for the period 1881-90 to nineteen for 1901-10. Russia 

 shows a corresponding fall from twenty-six to twenty-three ; 

 only newer countries — -Canada, Australia, the Argentine — 

 show large increases. Generally in a country the obvious 

 resources are the first used and the first to reach maximum 

 development, and among these are agricultural resources. 

 Later developments lead to the growth of an industrial 

 population. The order seems natural and inevitable, and 

 Canada and the United States may be taken as types of the 

 earlier and later stages in the evolution of a country. 



Wheat is produced as a rule at a distance, often very great, 

 from the industrial centres in which it is consumed, and the 

 cost of transport forms an important if not large part of the 

 cost of the food. The possibility of local production in any 

 commodity depends on, among other things, the cost of the 

 same commodity when imported, and the cost of the home 

 product is simply the cost of production.* Import and local 

 production tend therefore to a state of conditional equilibrium, 

 and the condition may be represented by the formula due to 

 Professor Dickson (loc. cit.), slightly modified: 



/ +l£ E + T, 



where / represents cost of local production, E cost of produc- 

 tion at a distant place, the cost of transport from which is 

 represented by T. The state of true equilibrium is ideal, and 

 there will always be an excess on one side of the equation 



representing the merchant's profit, and indicating whether 

 imported goods or local products form the main supply. 



Scientific statistical study is extremely important in 

 Economic Geography. It should be more widely cultivated 

 because it gives, as it were, a partial differential equation in 

 which variation is expressed with respect to one variable and 

 variation with respect to a complex of others is implicit, and 

 to which a general solution can be found. The essential is 

 that the study be scientific and rigid. Taking wheat in 

 production and distribution as the variable, the solution gives 

 these final results with regard to the redistribution of man : 

 (a) intensive methods of cultivation will be adopted and lead 

 to increase in manual labour, and consequently to increase in 

 density of population in regions mainly agricultural and thinly 

 populated at present ; (b) cost of food will increase, and this 

 will result in an alteration of equilibrium in remuneration for 

 work of all kinds, and in increase of agriculture in countries 

 now almost wholly industrial ; (c) agricultural and industrial 

 areas will be more closely intermingled, but there will be no 

 less centralisation than at present, and nodal towns will tend 

 to become huge in size. 



GEOLOGY. 



By G. W. Tyrrell, A.R.C.Sc, F.G.S. 



CALCAREOUS ALGAE AS ROCK-FORMERS.— This 



interesting but neglected subject was taken up by Professor 

 E. J. Garwood in his Presidential Address to the Geological 

 Section of the British Association. Whilst examining the 

 Lower Carboniferous rocks of the North of England, Professor 

 Garwood was impressed by the abundance of nodular 

 structures at certain horizons, and the large areas over which 

 these structures extended. Examined microscopically the 

 nodules were found to be organic, and to consist largely of the 

 calcareous alga known as Solenopora. This was the starting 

 point of an investigation which proved calcareous algae to 

 play a much more important part in the formation of limestone 

 deposits than had hitherto been considered. It was also 

 shown that certain forms became dominant over wide areas 

 at the same geological period, and might be used as proof of 

 the general contemporaneity of two deposits. As an example 

 is cited the abundance of Solenopora compacta during 

 Llandeilo-Caradoc times over an area covering the Baltic 

 Provinces, the British Isles, and Canada. The presence of 

 calcareous algae, which flourish best in the clear, shallow 

 waters of bays and lagoons, also furnishes evidence as to the 

 conditions prevailing during the accumulation of the rocks 

 containing their fossil remains. 



THE ENRICHMENT OF SULPHIDE ORES. — The 

 principle of the secondary enrichment of sulphide ores, 

 announced almost simultaneously and independently by S. F. 

 Emmons, W. H. Weed, and C. R. Van Hise in 1900, has 

 received much discussion in the intervening thirteen years, 

 and has been made the subject of a bulky Bulletin (No. 529) 

 of the United States Geological Survey, by W. H. Emmons. 

 The principle is simple. Under the influence of atmospheric 

 weathering sulphide ores break down and form soluble 

 salts, chiefly sulphates. When conditions are favourable 

 these acid solutions will be carried downwards, generally 

 along the channels afforded by the fissured zone which 

 contains the ore-body. The unoxidised rocks below the 

 ground-water level are in general alkaline, and acid solutions 

 encountering them in regions where air is excluded will lose 

 acidity, and certain of the metals they contain will be 

 precipitated. Also if the solutions of metallic sulphates 

 encounter sulphides in depth, precipitation of metals may 

 ensue ; or there may be an interchange between the metals in 

 solution as sulphates and the metallic sulphides. As a 

 consequence of these reactions certain parts of the ore-body 



* Exception may be taken to the economics of the discussion. In the first place, a (more or less problematical) future position is 



considered up to and in which the nature of human (European) food continues as at present, and in which the questions of supply 



and demand are somewhat different. For simplicity the matter is taken as less complex than it really is : supply and demand at a 



price and changes in mode of living are ignored ; the question of whether land is or is not available does not necessarily arise. The 



whole is to be thought of as giving the "differential equation " of the last paragraph. 



