I think that reading that page some time age inspired me, when I built a bench for my little Record lathe, to put some sand inside a hollow top. The bench essentially has a shelf and a top which are torsion boxes filled with sand. I think that the principle is that the sand in the top is higher up and therefore has more of a dampening effect than that in the shelf. I also found something else about a chap who had filled the hollow sides and back of his bench with sand, perhaps more because he say them as available cavities which could hold ballast.
Seems to work, but then I've nothing to say that it wouldn't work if I got rid of all of the sand anyway. I'm certainly no engineer