290 Geographical Collections* 



pretty correctly indicated by combining the ratios of the heat and the 

 moisture, expressing the former of these in degrees of the centigrade scale. 

 Something, we know, depends on the distribution of the heat through the 

 different seasons ; but, as we do not aim at minute accuracy, this may be 

 overlooked. 



Annual rain. Mean annual 

 Latitude. inches. heat. Product. Ratio. 



60 16 7 112 4 



45 29 14 406 15 



i! 96 28 2688 100 



Thus, if the description of food were a matter of indifference, the same 

 extent of ground which supports four persons at the latitude of 60°, would 

 support 15 at the latitude of 45°, and 100 at the equator. But the food 

 preferred will not always be that which the land yields in greatest abundance : 

 and another most important qualifying circumstance must be considered, — 

 it is labour which renders the ground fruitful ; and the power of the human 

 frame to sustain labour is greatly diminished in hot climates. In the 

 torrid zone, in low situations, we doubt if it is possible for men to work 

 regularly in the fields for more than five hours a-day, or half the daily period 

 of labour in England. On these grounds, and to avoid all exaggeration, 

 we shall consider the capacity of the land to support population as pro- 

 portional to the third power of the cosine (or radius of gyration) for the 

 latitude. It will therefore stand thus in round numbers : — 



In England, the density of population is about 230 persons per square 

 mile ; but England is, in some measure, the workshop of the world, and 

 supports, by her foreign trade, a greater population than her soil can nourish. 

 In France, the density of population is about 160; in Germany it varies 

 from 100 to 200. Assuming, on these grounds, that the number of persons 

 whom a square mile can properly sustain, without generating the pressure 

 of a redundant population, is 150 at the latitude of 50°, we have 26 as the 

 sum which expresses the productiveness of this parallel. Then taking, for 

 the sake of simplicity, 35 as the index of the productiveness of the useful 

 soil beyond 30° in America, and 85 as that of the countries within the parallel 

 of 30° on each side of the equator, we have about 4,100,000 square miles, 

 each capable of supporting 200 persons, and 5,700,000 square miles, each 

 capable of supporting 490 persons. It follows, that if the natural resources 

 of America were fully developed, it would afford sustenance to 3,600,000,000 

 of inhabitants, a number five times as great as the entire mass of human 

 beings existing at present upon the globe ! The novelty of this result may 

 create perplexity and doubt on a first view ; but we are satisfied that those 

 who investigate the subject for themselves, will be satisfied that our estimate 

 is moderate. But, what is even more surprising, there is every probability 

 that this prodigious population will be in existence within three, or, at most, 

 four centuries. We are quite aware of the objections which may be raised 

 to this conclusion, but they all seem to us to admit of an answer. In parti- 

 cular, we would observe, that the expense and difficulty of transporting men 

 from situations where they are redundant, to others where vacant space 

 exists, which is so much felt in the Old World, will be incredibly facilitated 

 by the employment of steam navigation upon the innumerable rivers which 

 are ramified over four-fifths of the New Continent. 



The imagination is lost in contemplating a state of things which will 

 make so great and rapid a change in the condition of the world. We 



