[106] Mr. Muirhead (in his “Life of Watt,” pp. 428-9) mentions a few additional particulars which it seems worth while to record. Thus he states that the largest steamer built up to the year 1813 was the _Glasgow_ noticed above, of 74 tons and 16 horse-power; and that, in 1815, the _Morning Star_ of 100 tons and 26 horse-power, and, in 1815, the _Caledonia_ of 102 tons and 32 horse-power, were severally launched. He adds that, during his last visit to Greenock in 1816, Mr. Watt made a voyage in a steam-boat to Rothesay and back, and showed the engineer how to “back” the engine, it having been usual previously to stop the engine for some time previously to mooring. He further states that, in April 1817, Mr. James Watt, Jun., purchased the _Caledonia_ and, having refitted her, took her in October to Holland and up the Rhine to Coblentz; having thus been the first to cross the English Channel in a steam-boat. The average speed he obtained was seven and a half knots an hour. On her return to the Thames in 1818, Mr. Watt, Jun., made no fewer than thirty-one experiments with her on the river, resulting in the adoption of many material improvements in the construction and adaptation of marine engines. [107] At this period, Mr. Rennie, who planned the breakwater at Plymouth and new London Bridge, was “advising engineer” to the Admiralty, and on every occasion urged the application of steam-power to vessels of war. More than this, he hired at his own cost the Margate steam-boat, the _Eclipse_, and successfully towed the _Hastings_, 74, against the tide from Woolwich to Gravesend, June 14th, 1819. On this the Admiralty, supported by Lord Melville, gave up their objections.—Smiles’ “Lives,” vol. ii. p. 267.