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The elasticity of one atmosphere has been often proposed to be employed for locomotive as well as fixed engines. The first proposition that we can recollect was in a patent granted in 1799, to the late George Medhurst, entitled "a condensing wind-engine, capable of being applied to all kinds of purposes, in which steam, water, wind, or horses are employed."
It does not appear, from the specification of the patent that he applied his invention to the propulsion of carriages; though we have heard it stated that he did so apply it. He described his invention to consist in –
"condensing the air of the atmosphere in a strong and close vessel, which I call the magazine, by means of a windmill, so as to make it from ten to twenty times more dense than it is in its natural state. Secondly, I conduct that dense air from the magazine through a pipe, to the top of a cylinder, where it acts upon a piston, by its elasticity, without the aid of fire, and by these means keeps the machine in constant motion for a time, proportioned to the capacity of the magazine, though the wind do not blow. The object of my invention is to accumulate and preserve the regular power which the wind produces, so that it may be applied to machinery to produce a uniform and regular motion whenever it is coasted."
The ingenious inventor then proceeds to describe his condensing mechanism, and the construction of his vessels for containing the condensed air. But as no particular objects are specified for its application (except cursorily, the raising of water,) it would be out of place here to enlarge on the subject; and our only reason for noticing it now, is to show what degree of originality appertains to the next invention we have to introduce to the reader's attention.