463269 Ground plan of the Philadelphia Gas Works, printed by Friend & Aub, 11th February 1851 (litho) by American School, (19th century); 30 x 41 cm; Library Company of Philadelphia, PA, USA; (add.info.: Plan of the first Philadelphia Gas Works, expanded in 1850 after the designs of Cresson, the second chief engineer of the gas works, near the Schuylkill River on the 2200-2300 blocks of Market Street. Diagrams the coal stores, retort house, lime and coke sheds, lime kilns and house, purifying houses, gasholders, and railroad tracks. Includes a "References" key to coded symbols of buildings, including valve houses and meters. Works originally completed in 1834 after the designs of engineer Samuel V. Merrick . ); 穢 Library Company of Philadelphia ; American, out of copyright.