344 THE ADDRESSES, LECTURES, ETC., OF 



were sailing vessels and 137 steamers. The number of sailing 

 vessels included in these returns being 19,325, and of steamers 

 5,505, it appears that the steamer is the safer vessel, in the 

 proportion of 4*43 to 3'46 ; but the steamer makes on an average 

 three voyages for one of the sailing ship taken over the year, 

 which reduces the relative risk of the steamer as compared with 

 the sailing ship per voyage in the proportion of 13'29 to 3'46. 

 Commercially speaking, this large factor of safety in favour of 

 steam-shipping is to a great extent counterbalanced by the value 

 of the steamship, which bears to that of the sailing vessel per net 

 carrying ton the proportion of 3:1, thus reducing the ratio in 

 favour of steam shipping as 13*29 to 10'38, or in round numbers 

 as 4 : 3. In testing this result by the charges of premium for 

 insurance, the variable circumstances of distance, nature of cargo, 

 season and voyage have to be taken into account ; but judging 

 from information received from shipowners and underwriters of 

 undoubted authority, I find that the relative insurance paid for 

 the two classes of vessel represents an advantage of 30 per cent, 

 in favour of steam-shipping, agreeing very closely with the above 

 deductions derived from statistical information. 



In considering the question how the advantages thus established 

 in favour of steam-shipping could be further improved, attention 

 should be called in the first place to the material employed in 

 their construction. A new material was introduced for this 

 purpose by the Admiralty in 1876, when they constructed at 

 Pembroke dockyard the two steam corvettes, the Iris and Mercury, 

 of mild steel. The peculiar qualities of this material are such, as 

 to have enabled shipbuilders to save 20 per cent, in the weight of 

 the ship's hull, and to increase to that extent its carrying capacity. 

 It combines with a strength, 30 per cent, superior to that of iron, 

 such extreme toughness that in the case of collision the side of 

 the vessel has been found to yield or bulge several feet without 

 showing any signs of rupture, a quality affecting the question of 

 sea risk very favourably. When to the use of this material there 

 are added the advantages derived from a double bottom and from 

 the division of the ship's hold by means of bulkheads of solid 

 construction, it is difficult to conceive how such a vessel could 

 perish by collision either with another vessel or with a sunken 

 rock. The spaces between the two bottoms are not lost, because 



