used instead of a cradle. The distinctive features of the apparatus consisted of 'a section of a cylinder, which is fitted to the barrel of a musket by a bayonet socket; a rocket with a line attached to its stick is so placed in it that its priming receives fire immediately from the barrel'. The advantages were that the rocket was much lighter and more portable than the mortar; that the cost was much smaller; that there was little risk of the line breaking, because the velocity of a rocket increases gradually, whereas that of a shot fired from a mortar was so great and sudden that the line was frequently broken; the whole of Trengrouse's apparatus could, moreover, be packed in a chest four feet three inches by one foot six inches, and carried by vessels of every size, while Manby contemplated the use of the mortar only on shore, and the safety of the vessel depended therefore on the presence of an apparatus in the vicinity of the wreck. Recognition It was not, however, until 28 February 1818, after many journeys to London, that Trengrouse exhibited his apparatus before Admiral Sir Charles Rowley. A committee was appointed, and on 5 March it reported 'that Mr. Trengrouse's mode appears to be the best that has been suggested for the purpose of saving lives from shipwreck by gaining a communication with the shore; and, so far as the experiments went, it most perfectly answered what was proposed;’ it was also suggested that a specimen apparatus should be placed in every dockyard that naval officers might become familiar with its working. In the same year a committee of the Elder Brethren of Trinity House also reported in its favour, and recommended that 'no vessel should be without it.' The government ordered twenty sets, but afterwards preferred to have them constructed by the ordnance department, and paid Trengrouse £50 compensation. In 1821 the Society of Arts awarded him their large silver medal and thirty guineas for the invention. Alexander I of Russia also wrote Trengrouse an autograph letter, presented him with a diamond ring in recognition of the usefulness of his apparatus, and invited him to Russia; but apart from the prize awarded by the Society of Arts and the compensation paid by the government, Trengrouse reaped no pecuniary reward from his invention. An improved rocket was invented by John Dennett in