How does a dog know what direction to go with a track?

Ive been hunting and training hounds for thirty years and this question has been asked a thousand times in as many hunts. the truth of it is they hit the track the wrong way as often as they hit it the right way! contrary to a post earlier, the track deminishes (smell) as the track gets older, the theory behind what he was explaining is right only in that a drag runs out of smell but a animal doesnt as a matter of fact thier smell intensifies as they begin to get hot and sweat. there are several factors that contribute to the rate of the deterioration of a track, moisture, wind ,temperature, etc.

the hotter a track is the more likely a dog is to start it the wrong way, after being on the track for a bit the dog figures out that the further he takes the track that its either getting stronger or its getting weaker. He instinctively knows if its getting stronger he can run it faster and harder. If its deteriorates on him he will turn around and run it the other way.

I know you have seen a dog get excited and start running around rapidly in circles with his tail wagging vigerously and you have probably said he smells one! well you were right and the reason he is all over the place is because he is trying to figure out witch direction to run the track!

in a few mins he is gone and shortly after he is bayed! does this make since?