The gas engineer of the last century. The 4th Thomas Hawksley lecture.** first Thomas Hawksley lecture, by E. B. Ellington, proceedings, I.Mech.E., 1913, page 1215. second lecture, by W. B. Bryan, 1914, page 811. Third lecture, by Dugald Clerk, D.Sc., F.R.S., 1915, page 591. The gas engineer of the last century.