[To] mechanical progress there is apparently no end: for as in the past so in the future, each step in any direction will remove limits and bring in past barriers which have till then blocked the way in other directions; and so what for the time may appear to be a visible or practical limit will turn out to be but a bend in the road.(Opening address to the Mechanical Science Section, Meeting of the British Association, Manchester.)
Osborne Reynolds
barriers, limits, mechanical, progress, science