File:HydraulicMain.png

Summary
Cross-sectional drawing of hydraulic main, cleaned up, converted to black and white. From: Secretary, Trustees Gas Educational Fund. Catechism of Central Station Gas Engineering. Charles F. Bloom, Printer and Bookbinder: New York City, New York State, United States of America (1909). Pg. 76. Available online at https://archive.org, texts section.