In which book is it written that the only measurable physical quantity is the length? Task. In any book I've seen thoughts and images that very clearly illustrate the sequence of actions and implicit assumptions when measuring something. The result has been that in any measurement key was the length measurement. For example, in the book Fundamentals of Physics Extended, Halliday&Walker correctly begins the description of start a physics - measurement is the basis of physics. The following describes what is the length. Then time and so on. But! Is not described that the measurement of time in a mechanical watch arrow implicitly counts the length of the circumference by minute and hour-markers. Question. I don't remember in which book these thoughts are clearly documented. Please tell me this book. Thank you.