The acceleration principle is normally attributed 
to Aftalion (Les crises périodiques de 
surproduction, Paris 1913, vol. 2, pp. 356­70), 
JM Clark (Business Acceleration and the Law of 
Demand: A Technical Factor in Economic Cycles, 
Journal of Political Economy, 25, March 1917, pp. 
217-235) and C.F. Bickerdicke (A non-monetary 
cause of fluctuations in employment, Economic 
Journal 24 (1914) , September, pp. 357­70)

Harrod picked it up late in 1934 from the 
exposition in a draft of Haberler's Prosperity 
and Depression titled "Systematic analysis of the 
theories of the business cycle" (mimeo, August 
1934). For an account see my own The making of 
Harrod's dynamics, Macmillan 1999, section 3.1 
(in the remainder of the chapter I relate how he 
gathered the other pieces of his mechanism and joined them together).

On JM Clark on this issue, see L. Fiorito, An 
Institutionalist's Journey into the Years of High 
Theory: John Maurice Clark on the 
Accelerator-Multiplier Interaction, Journal of 
the History of Economic Thought, December 2007, v. 29, iss. 4, pp. 437-52

Daniele Besomi