This is from p. 227 of Schumpeter's 1939 _Business Cycles_.

"The electrification of the household may involve many 
discontinuities incident to the setting up of new production 
functions when looked at from the standpoint of individual firms and 
yet appear, when looked at from other standpoints, as a continuous 
process proceeding steadily from roots centuries back.  By one of the 
many roughnesses or even superficialities forced upon us by the 
nature of the task this volume is to fulfill, we may characterize 
this as a difference between microsopic and macroscopic points of 
view: there is as little contradiction between them as between 
calling the contours of a forest discontinuous for some and smooth 
for other purposes."

Barkley Rosser