From Architectural Record, April, 1928. Read a PDF of the original article here. 

The country between Madison and Janesville, Wisconsin, is the old bed of an ancient glacier-drift. Vast, busy gravel-pits abound there, exposing heaps of yellow aggregate, once, and everywhere else, sleeping beneath the green fields. Great heaps, clean and golden, are always waiting there in the sun. And I never pass without emotion – without a vision of the long dust-whitened stretches of the cement-mills grinding to impalpable fineness the magic-powder that would “set” it all to shape and wish, both, endlessly subjects to my will.