15 



Peninsular and Oriental Company, the Royal Mail Company, and 

 the Pacific Steam Navigation Company, were all in operation. 

 From that time onward, sails have sunk to a more and more 

 subordinate position with regard to steam, and the use of steam-ships 

 has gradually extended to the trade with China and Australia. 



The Lecturer proceeded to indicate some of the principal causes 

 whose operation has been so beneficial on steam-ship design. These 

 were enumerated as follows : — 



1. The substitution of iron for wooden hulls. 



2. The substitution of screws for paddles. 



3. The construction of more economical types of engines and 



boilers. 



The use of iron makes the hull 20 to 30 per cent, lighter, and 

 enables ships to be built of sizes and proportions quite impossible 

 with wood. This increase of size is a great source of economy. 

 Comparing, for instance, two steamers — one weighing 1000 tons, 

 the other weighing 8000 tons ; if the smaller vessel carried 400 tons 

 of cargo, and burned 100 tons of coal on a voyage, the larger vessel 

 would carry about 4000 tons cargo over the same distance at the 

 same speed, burning about 400 tons only. 



The "Great Eastern" must, however, for several reasons stated, 

 be pronounced too large for successful employment in general service. 

 The largest steamers now being built are not one-half as heavy as 

 the "Great Eastern." 



The most important result of improvements in marine engineer- 

 ing, has been a great increase of economy in fuel consumption. 

 A first-class trans-Atlantic steamer now burns 100 tons of coal 

 daily ; with engines such as those in vogue thirty years ago she 

 would burn 350 tons a day, and would either have to carry so large 

 a supply of coal that she would practicall}- be deprived of cargo- 

 carrying capacity, or, to keep down the coal supply, her power and 

 speed would have to be greatly diminished. 



Since the opening of the Suez Canal, steamers have gained 

 enonnously upon sailing-ships in the trade with India and China. 

 The voyage from Plymouth to Bombay has been reduced thereby 

 from 10,000 miles to 6,000 ; to China from over 13,000 to less 



