102 THE GENERAL THEORY OF EMPLOYMENT BK. III

£68,000,000 by 1933, as compared with new advancesof £103,000,000; and to-day the repayments areprobably still higher.

That it is investment, rather than net investment,which emerges from the statistics of output, is broughtout forcibly and naturally in Mr. Colin Clark’s NationalIncome , 1924-1931. He also shows what a large pro-portion depreciation, etc., normally bears to the valueof investment. For example, he estimates that inGreat Britain, over the years 1928—1931,1 the invest-ment and the net investment were as follows, thoughhis gross investment is probably somewhat greaterthan my investment, inasmuch as it may include a partof user cost, and it is not clear how closely his “netinvestment” corresponds to my definition of this term:

(£ million)

1928

1929

1930

1931

Gross Investment-Output

791

731

620

482

“Value of physical wasting

of old capital” . .

433

435

437

439

Net Investment .

358

296

183

43

Mr. Kuznets has arrived at much the same con-clusion in compiling the statistics of the Gross CapitalFormation ( as he calls what I call investment) in theUnited States, 1919—1933. The physical fact, towhich the statistics of output correspond, is inevitablythe gross, and not the net, investment. Mr. Kuznets hasalso discovered the difficulties in passing from gross in-vestment to net investment. “The difficulty”, he writes,“of passing from gross to net capital formation, that is,the difficulty of correcting for the consumption ofexisting durable commodities, is not only in the lackof data. The very concept of annual consumption ofcommodities that last over a number of years suffers

1 Op. cit. pp. 117 and 138.