Original oil and gas trade magazine vintage ad for SCHLUMBERGER WELL SURVEYING CORPORATION of Houston, TX. Now You Can Get Two Services for the Price of One. The Schlumberger Microlog plus the Schlumberger Section Gauge. No added rig time, no added costs. Don't just ask for a Microlog - ask for a Schlumberger MicroLog-Caliper. Unique 1955 old two-sided petroleum oilfield service industry equipment magazine advertisement. On the reverse side is is a continuation of the SCHLUMBERGER WELL SURVEYING CORPORATION ad. Pictured is the Microcaliper, Microlog, and the Electrical Log of an East Texas well. Schlumberger, The Eyes of the Oil Industry. Front and back side.