john elder teriminin İngilizce İngilizce sözlükte anlamı
born March 8, 1824, Glasgow, Scot. died Sept. 17, 1869, London, Eng. Scottish marine engineer. In 1854 he developed the marine compound steam engine (using both high-and low-pressure steam), which enabled seagoing vessels to save 30-40% of the coal they had been burning and helped make practical long voyages on which refueling was impossible