Original oil and gas trade magazine vintage ad for SCHLUMBERGER of Houston, TX. On the Measurement of Depth Used by Seafaring Men for Centuries, The Lead Line answered the Important Question of Water Depth. In oil wells, precision measurements are required at much greater depths. In logging, testing, and perforating, dependable Schlumberger depth measurements are confidently accepted by the oil industry. Pictured is a Sounding Lead LIne, and a Bahama Sloop. This unique 1962 old petroleum oilfield drilling equipment industry magazine advertisement would display beautifully matted and framed.