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Show Concrete That Floats A block of concrete floated on water, wa-ter, bobbing up and down like a cork, at the school of practical science, University of Toronto, recently, when Prof. G. R. Anderson, carried out an unusual experiment. Known as cellular concrete, this floating stone was made on a system, ana logons to raising a bread with yeast. The cement, gravel, water and sand, were put into a mixer and a carbon dioxide forming chemical was added. add-ed. The cement then set into a hard porous substance lighter than wood. Professor Anderson says It has remarkable re-markable resistance to sound. |