Miracle concrete: the great modern industry (1909)
Miracle Pressed Stone Co. · Miracle Pressed Stone Co. · leaf 93
This consists of a screw arrangement whichcertainly does not permit of the least snap or jar in contracting.Notice how turning the screw to the left lowers the upper armsattached to the shell and raises the lower arms. In this waythe distance from the circumference of the mold to the center…
