I was emailed the following, and I thought I would share it with you:
Occasionally I see two clocks together with slightly different times displayed and it occurs to me that those two machines are just sitting there counting. One is counting a little faster than the other and each displays how far it has counted and we consider that a measurement of time.
Consider what’s inside a clock. The old fashioned grandfather clock with a pendulum swinging back and forth responds to gravity. If I put it on the moon it will run slower, so I have to say it is a machine that measures gravity. My old tick-tock wrist watch has a little spring attached to a wheel and the wheel goes back and forth at a speed that depends on the stiffness of the spring. There is an adjustment inside that lets me adjust the length of the spring (its stiffness), so this machine measures spring stiffness. My old plug-in electric clock has a wheel that spins at a speed determined by the 60-cycles-per-second electricity I get from the power company. If I take it to Europe where they have a 50 Hz electrical supply, it will run at 5/6 the speed, so I have to conclude that this machine counts alternating current electrical cycles. Whatever clock I consider, I find a device measuring or counting something as it occurs and expressing it as time.
It seems that, if a clock measured time, I could put it in the presence of more or less time and it would respond accordingly.
When I put water in my measuring cup and it indicates I have one cup of water I can understand how the cup measures water. If I use water in my house, the dials on the water meter spin to measure the water. When I use more water, they spin more. When I shut off the faucet they stop. I can understand that this machine is measuring water. But I have to ask, can you show me a machine that measures time?
what do you think?
A Day in the Life of a Presson... 
No, I can not show you an instrument to measure time. I can, however, express my appreciation for your intellect. It is funny how many people take things for granted, like the notion that a clock measures time. You’ve at least uncovered some assumptions. It is better to think of time force which moves everything in existence. For example if you are on a train and have no reference point with which to judge your speed how would you be able to tell how fast you are going?
I appreciate your insight. You completely nailed the inference that time is really a perception and nothing more.
From what I can gather, time is supposed to be a physical property of the universe i.e. spacetime is physical; but time is a system of measurement, not something to be measured.
http://discovermagazine.com/2007/jun/in-no-time
As I understand it from relativity theory, time is not a substance to be measured it is simply one of the dimensions of a hypothetical fabric in which matter and energy sit in our universe. Measuring time is like trying to measure upness or sidewaysness, there are artificial frameworks against which such a measurement might be made but there is no absolute zero, nor are there any absolute units.
db