^{Page 330 note 1} Billion is here used throughout in the American sense of one thousand million.

^{Page 332 note 1} Based on a weighted average and straight-line extrapolation of the data in Kuznets, Simon, Six Lectures on Economic Growth (Glencoe, 1959), p. 27.Google Scholar

^{Page 332 note 2} Detailed aspects of economic changes over the last century are discussed in the following studies of mine: ‘Rates of Industrial Growth in the Last Century, 1860 to 1958’, in Economic Development and Cultural Change (Chicago), IX, 3, 04 1961;Google Scholar ‘The Economic Distance between Nations: its origin, measurement and outlook’, in The Economic Journal (London), LXXIV, 03 1964;Google Scholar ‘Main Features of Economic Growth over the Last Century’, in the Indian Economic Journal (Bombay), 03 1964;Google Scholar ‘What Holds up Agriculture?’, in the Economic Weekly (Bombay), XV, February 1964.

^{Page 333 note 1} Owing to the severe statistical limitations, the figures for population and output are to be treated as broad orders of magnitude, rather than precise statistical measurements; they are rounded to the nearest 5 or 10.

^{Page 333 note 2} Population estimates for 1850 are based on W. S., and Woytinsky, E. S., World Population and Production (New York, 1953),Google Scholar and for 1960 on U.N. documents.

^{Page 333 note 3} Output estimates are explained more fully in my article, ‘The Economic Distance between Nations’; they are calculated at constant (1960) prices.

^{Page 333 note 4} ‘Industrial countries’ means those that had become industrialised by 1960, i.e. the following: Austria, Australia, Belgium, Canada, Denmark, Finland, France, Western Germany, Ireland, Israel, Italy, Luxembourg, the Netherlands, New Zealand, Norway, Sweden, U.K., U.S.A., U.S.S.R., and all of Eastern Europe.

^{Page 334 note 1} The explosive power of cumulation at compound rates may be seen from the table below, which summarises the results of growth at annual rates of from 1 to 10 per cent for periods of 20, 50, and 100 years. Index Numbers of Per Capita Output (Year 1 = 1.00)

Source: Kent, Frederick C., Compound Interest and Annuity Tables (New York, 1956),Google Scholar Table 1; calculated to only one decimal place after the index rises over 10, and to the nearest whole number when it goes beyond 100.

^{Page 335 note 1} See my article, ‘Main Features of Economic Growth over the Last Century’.

^{Page 336 note 1} Gilbert, Milton and Kravis, Irving B., Comparative National Products and Price Levels (Paris, 1955), p. 165.Google Scholar

^{Page 337 note 1} Sources: based on national statistics for industrial countries (defined as in Table 1); and U.N. Economic Commission for Africa, Industrial Growth in Africa (New York, 1963),Google Scholar ch. 1. The figures based on domestic product at factor cost are very crude and have therefore been rounded to the nearest 5 or 10.

^{Page 337 note 2} Value of output in each sector related to the whole population, and not to the number of persons engaged in that particular sector.

^{Page 337 note 3} The data in this column are not based on detailed price relatives of all the items in national accounts, but are the product of a rough and ready calculation, with an arbitrary adjustment for agriculture.

^{Page 341 note 1} Estimates should be treated as broad orders of magnitude only.

^{Page 344 note 1} The I.C.O.R. may be defined as the ratio of a given increment in capital resources to the resulting increment in annual output. Increments in capital are here measured in terms of gross capital formation.

^{Page 345 note 1} Source and methods: based on Table 3; estimates of capital derived by assuming incremental capital output ratio (I.C.O.R.) to be 1.5:1 in agriculture, 2.5:1 in total industry, and 4:1 for the other sectors. The derived over-all I.C.O.R. for both the periods would thus be a little under 3:1.

^{Page 345 note 2} Egtimate based on development plans where available, and national statistics.

^{Page 348 note 1} Such foreign aid need not be regarded just as charity. Africa has also contributed heavily to the development of the industrial countries. For instance, the estimated value of the slaves in the United States on the eve of the Civil War was a little higher than the total capital investment in the modern sectors—manufacturing, mining, transport, and communications. A rough estimate of what the Europeans have received from Africa since the turn of the century may be about $100 to $150 billion in 1960 prices—one-third of which may be assumed to have been consumed in Africa, one-third invested in Africa, and the remaining one-third sent outside the continent. Africa's pressing demand for external aid now may therefore be interpreted as a reverse lend-lease rather than charity.