SIR ARTHUR JOHNS, director of naval construction, for his Andrew Laing lecture to the North-East Coast Institution of Engineers and Shipbuilders on Novem ber 2, took for his subject “Progress in Naval Con struction”. Beginning with a comparison of the Navy in 1874 and 1934, he dealt in turn with materials, the development of the capital ship and of cruisers, torpedo vessels, submarines, aircraft on warships, model experiments, welding and stability and strength. Nothing perhaps was more striking than the figures he gave regarding tonnage, horse-power and speed. The displacement tonnage of our fighting ships in 1874 was 825,000 as compared with 1,275,000 of to-day, while the corresponding figures for horse power are 590,000 and 9,500,000. A cruiser of 1874 had engines of 4,500 horse-power and a speed of 14 knots; a cruiser of to-day develops 72,000 horse power and has a speed of 32 J knots. Though Sir Arthur John's review was necessarily a cursory one, it was a valuable authoritative review of the main lines of progress and contains references to many of the most interesting vessels ever launched. He paid an eloquent tribute to the work of William Froude, whose theory of a propeller's operation is still the simplest and most representative, and whose method of computing the skin resistance of full-sized ships has stood the severest tests. Regarding the stability of ships, this has been the bugbear of naval architects since the thirteenth and fourteenth centuries, and even after Bouquer had defined the meta-centre and shown how its position was determined, Atwood in a paper to the Royal Society proved to his own satisfaction that the meta-centre was a mere mathe matical curiosity, useless to the naval architect. It was the researches of White and John after the capsising of the Captain in 1871 which made a marked advance in our knowledge of the stability of a ship and of the features which improve or ad versely affect it.