Motor heads to show carbon, California Testing Laboratories, Southern California, 1940

14 photographs of motor heads to show carbon, Southern California, 1940. "Subject: Motor heads to show carbon, (McMillan), (start of test), Ford & Chev[rolet]; Client: Calif[ornia] Testing Laboratories, 1429 Santa Fe Ave[nue], Yr. 15 48, Mr. Cornell; Original Print Order: 1 ea[ch]; Size: 8x10; Finish: gl[ossy]; PRINTING ON NEGS; Re-Order: 1 ea[ch], 1 #11, 12, 13, 14, 1 #14; Size: 8x10, 8x11, 11x14; Finish: gl[ossy]; Mount: 1/4" margin - see Harry; Job: 6-25-146; Year: 1940" -- on envelope front. "Operator's Report-Name: Joe; 14 Original Photographs-Size: @ 2.50, total negs [ilg]; Amount: 35.00" -- on envelope back.