I really can't imagine anyone throwing their glasses and coat down the chimney before him. What if he chickened out, changed his mind, or realized he couldn't fit in the chimney? "Well, my coat and glasses are gone......: (" It was like 15 degrees. I also kind of doubt he took his coat off. He may or may not would have put his glasses in his coat pocket before descending.
The chimney "expert" was describing a generic chimney/fireplace setup and not the specific chimney in this house. There has been mention of chimneys "narrowing" as you go down (and I'm sure this is a thing with more modern chimneys), but this one was built in 1850. Why was the opening 9 x 13? Bricks. That is the size you get with a 2 brick by 2.5 brick structure. The chimney also (at least originally) went all the way down to the first floor. This leads me to think that the chimney was a vertical "column", and a consistent 9 x 13 from the first floor to the roof. Therefore, i question the compression cause of death determination.
My theory is as follows: Harley descended feet first. The space was so small that he descended with his arms above his head. Whether he "fell" or was able to control his descent, his coat was pulled off. The chimney was apparently blocked off at the second floor. So he gets to the second floor with his coat now sitting on top of his head. He realizes he is stuck and at some point feels the flue hole (which I'm guessing to be around 6 feet above the floor.....and right about where his arms above his head would be).
I originally thought that him pushing his coat out of the flue was because he was trying to leave "bread crumbs." I have since thought of a few other possible reasons. One is that his coat sitting on his head was annoying him and he got it out of the way by pushing it through the flue. The other possible reason is more disturbing. That possible reason is that the chimney was filling up with the carbon dioxide that he was exhaling, and he was having trouble breathing, and the coat was partially blocking the path to fresh air. Now I'm no scientist, so i really don't know how possible him asphyxiating in there due to him using up the oxygen is. The top of the chimney is open, but it was pretty far away. There was also the flue hole to let in air, so I'm not really sure about the science of it all. The inside of the chimney is a relatively small space with a limited amount of oxygen (if the oxygen is not replaced/air circulated). Supposedly carbon dioxide is heavier than air, and would theoretically eventually fill up the bottom of the chimney. Again, especially considering the flue hole, I don't even know if it would be possible for him to use up the oxygen.
If not possible, I would think that there is a good chance that he died from dehydration. I wonder if the autopsy can determine the difference between dehydration and asphyxiation with the amount of decomposition present?