The rivalry in the various over-sea trades was very great, and no sooner did one shipowner secure a vessel which surpassed its competitors than other owners sought to improve upon it. The sailing ships were soon obliged to give way to the steam auxiliary vessels, especially when craft like the _Lightning_ appeared. The _Lightning_ was built by the Hendersons of Glasgow, and so pleased were her owners, Messrs. Apcar of Calcutta, and their representative, Captain Durham, with her, that he ordered the _Thunder_. The _Thunder_ was built by Mr. Lungley at his yard on the Thames and engined by Messrs. Dudgeon, and was an improved edition of her predecessor. The _Thunder_ was launched in December 1859, and soon demonstrated that she was the fastest steamer yet provided with a screw propeller. She was a handsome vessel, ship-rigged, with clipper bows, and her masts and funnels had a slight rake which gave her a very attractive appearance. Her length was 240 feet between perpendiculars, beam 30 feet, depth 22¹⁄₂ feet, and her tonnage, builder’s measurement, was 1062. The engines were of 210 nominal horse-power with cylinders of 55 inches diameter, and a piston stroke of three feet. A peculiarity in her boilers was that they consumed the fuel and heat in furnaces and tubes to the point that the remainder escaped up the chimney and heated the superheater to a temperature of 300 degrees, without regulation. On her trial trip she travelled at the rate of at least seventeen statute miles per hour, and afterwards did even better. Her coal consumption also was the lowest then attained, being about one pound per indicated horse-power per hour. Her screw was of the ordinary type and was placed outside the rudder. The _Lightning_ and the _Thunder_ were both employed in the China trade. [Illustration: THE “THUNDER.”]