The second contract, calling for weekly sailings, necessitated a larger fleet of steamers. To meet this demand four new ships were built, and took their places on the line in 1848, namely, the _America_, _Niagara_, _Canada_ and _Europa_. Each of these was 251 feet long, of 1,800 tons burthen and 750 horse-power. They had an average speed of 10½ knots an hour. And so, from time to time, as the exigencies of trade and the need for enlarged passenger accommodation demanded, fresh additions were made to the fleet, each succeeding ship surpassing its predecessors in size, equipment and speed. The _Persia_, built in 1856, was the first of the iron boats: the _Scotia_, in 1862, was the last of the paddle-wheel steamers. They were both very fine ships of 3,300 and 3,871 tons, respectively, accounted the best specimens of marine architecture then afloat. The _China_, launched in 1862, was the first Cunard single-screw steamer. She was followed, in 1867, by the _Russia_, the queen of ocean steamers in her day. Passing a number of intervening ships, we come, in 1881, to the _Servia_, the first of the line built of steel—a magnificent vessel, 515 feet long, 7,392 tons, 9,900 horse-power, and attaining a speed of 16.7 knots. In the meantime important changes had been transpiring in the constitution of the Cunard Company and its environment. The original shareholders had been by degrees bought out by the founders, so that the whole concern was vested in the three families of Cunard, Burns, and MacIver. Sir Samuel attended to the business in London, Mr. Burns in Glasgow, and Mr. MacIver in Liverpool, and never was any business better managed than by these men and their successors. In 1878 it was deemed expedient to consolidate the interests of the partners by the formation of a joint stock company with a capital of £2,000,000 sterling. The three families interested in the concern took up £1,200,000 in paid-up shares. No shares, however, were offered to the public until 1880, when a prospectus was issued, setting forth the necessity for additional steamships of the most improved type, involving a large outlay of money. The shares were readily bought up and measures were taken to increase the efficiency of the fleet, which had become at length imperative owing to the keen competition of rival lines. This was inevitable. [Illustration: THE “SCOTIA,” LAST OF CUNARD PADDLE-STEAMSHIPS, 1862.]