Miracle concrete: the great modern industry (1909)
Miracle Pressed Stone Co. · Miracle Pressed Stone Co. · leaf 16
rice $7.00. No one doubts the strengthening value of an air spacewhen in the form of a hollow iron tube. In the form of astone column the principle is the same, and the hollow columnis stronger than if it were solid. In the form of a cementwall, with single air spaces, there is a series of hollow… … A B D Showing the Narrow Spans in a Miracle Block. Showing the Wide Spans in a Single Air Space BlocV..
