[agere_contra]

you can't get more light in through the hole than hits the hole to start with

The thing is you have extended the 'light-catching area' above the roof. So you have increased the amount of light coming through the roof at all times of day except noon.

[PrayAndVoteConservesInLibsOut]

Thanks for this info. Also, to those interested, the article explains it this way:

“Refraction is the bending of light, which is caused by a change in its speed.
The speed of light is determined by the density of the substance through which it passes.
So refraction occurs when light passes from one substance to another with a different density - eg from air to water
In the case of the “Moser lamp”, sunlight is bent by the bottle of water and spread around the room.

Thanks for posting everyone.

[from occupied ga]

The thing is you have extended the 'light-catching area' above the roof

NOT if you look at the pictures in post 10.

[afraidfortherepublic]

This sounds to me like it work a lot like those little, round skylights that they sell. A lot more light enters the room than just the diameter of the hole because there are reflectors inside the shaft that enhance the light.

http://www.solatube.com/