To James Watt, notwithstanding that his work and ingenuity were expended for the purpose of land engines, belongs the honour of having removed the most harassing obstacles which were delaying the full and entire possibility of the marine steam engine. In the chain of discoveries which leads back into early times, without whose cumulative effect he himself would not have done what he did, James Watt comes immediately next to Thomas Newcomen. Despised in his weak, delicate boyhood by his companions, his is another instance of the stone which the builders rejected becoming the head corner-stone. Or, to put the proposition in another way, Watt absorbed all the existing good that there was in the latest engineering knowledge, and advanced that several steps further until it reached the goal of practicability. In the Newcomen engine there were several notable defects which marred its usefulness, and it was not until these could be improved upon that there could possibly be a future for the steamboat. This type of “machine” was not closely enough related to the work which it was called upon to perform. Its pre-eminent fault lay in the fact that the condensation took place in the cylinder. This meant a considerable waste, for after the latter had been made cool by the admission of the cold water for condensing the steam, the cylinder had to be heated again before every upward stroke. Heat, in fact, was literally thrown away. It was in the year 1764 that Watt, while endeavouring to repair a model of one of these Newcomen engines and to remedy its poor performance, was struck by the inadequacy of its mechanism and realised that some means should be found to ensure a greater economy of steam. From his ingenious brain, therefore, came an improvement. He provided for the condensation to take place not in the cylinder but in a separate condenser, in which a jet of water was to spray, and finally the condensed steam, the injected water, and the air which had also found its way in, were to be drawn off by means of an air-pump. After a delay of several years Watt was introduced to Matthew Boulton, founder of the Soho Engineering Works, near Birmingham, and in 1769 Watt’s invention, embodying the principle of the separate condenser, was patented. Although he had worked out his idea as far back as the year 1765, it was not till four years after that he had the means to secure its protection. In the specification for his patent Watt enunciated what is appreciated as an essential doctrine to-day, that the walls of the cylinder should be maintained at the same heat as the steam which was about to enter into the cylinder. And he proposed to bring about this improvement by adding an external casing to the cylinder, leaving a space between the casing and the outside of the cylinder itself and keeping always in this space steam so as to preserve a high temperature.