Motor tampers in action at El Monte, Calif., 1937

6 photographs of a man using a plate compactor on dirt, El Monte, California, 1937 July 21. "Client: The Calhoun Co[mpany], 1151 So[uth] Broadway, Att[entio]n: Mr. Robert A. Weir; [diagram of print size and margins]; Operator's report - name: Jack; Amount: 12.00; 30 miles: Transportation at 7 c[ents] - Amount 2.10; 2-1/2 hours: time - Amount 5.00; negative retouching - Amount 3.00" -- on envelope.