Model of Savery's engine, before 1754
Savery patented his "fire engine" or atmospheric engine in 1698 and presented it to the Royal Society the following year. Although it was a major technological breakthrough it did suffer considerable problems, the principal one being that the steam had to be held at very high pressures and temperatures which sometimes melted the solder and blew apart the boiler. According to Desaguliers "these discouragements stopped the progress and improvement of the Engine" making it useful only for raising water for gentlemen's seats and not in mines where the demand was greatest. Desaguliers and his colleagues studied the design of the early engines and made models and improvements. Demainbray used this model with the model Newcomen engine in his course on pneumatics. This model, but not the Newcomen model, was shown as a working demonstration, considerable attention being given to methods of preserving the boiler and repairing the cylinder as "being of utmost moment to persons concerned in Mines".
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