17 



in association with the simpHcity and durability so 

 desirable in marine engines, remains to be proved. 



2. The use of steel instead of iron enables weight to be saved 



on the hulls of ships, and to be transferred to cargo or 

 machinery. In a merchant steamer of about 8000 tons 

 displacement, quite 400 tons would be saved by the use 

 of steel, and the 3000 tons of coal and cargo she can 

 carry might be increased by that amount. 



3. Improvements in the methods of steam-ship design, enabling 



greater precision to be given to the proportioning of 

 engine power to speed. In connection with these im- 

 provements, mention was made of the labours of the late 

 Mr. Froude. 

 A reference to the want of exact knowledge respecting the 

 action of screw-propellers, brought the Lecture to a conclusion. 



Note. — The matter of this Lecture appears in ColhurrCs United Service 

 Magazine, June and July, 1880. 



THUESDAY, JUNE 10th. 



ExcTJESiON TO Chatham Dockyard. — The first Excursion for 

 the year took place on June 10th, when, by special permission of the 

 Lords Commissioners of the Admiralty, the Members and their 

 friends, numbering about 70 persons, visited Chatham Dockyard. 

 The party was received at the gate by Admiral Beandeeth, the 

 Admiral Superintendent, who was accompanied by Mr. Beenats, 

 Superintending Engineer, and Messrs. Littlejohns and Stainee 

 of the Engineering and Constructors' departments. 



Under the guidance of the last three gentlemen, the party pro- 

 ceeded to view the " Polyphemus," a vessel of novel design now in 

 course of construction, described as a toi-pedo-ram. She is to carry 

 no guns, and will rely for her means of offence entirely on her 

 facilities for discharging torpedoes, and on her power of ramming. 

 She is built of steel, and is divided into a niimber of water-tight com- 

 partments ; her back is covered with aimour plates of compressed 

 steel, and she will float so low in the water that only a portion of 

 her " turtle back" will be exposed to fire. 



