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The Early English
ledge of the ancient organ, but now we have an independent authority; for the work of Hero was unknown to Vitruvius, and both describe, with considerable differences, the construction of the hydraulic and of the pneumatic organ.
Having briefly pointed out the treatise of Hero of Alexandria, for the benefit of those who think it worth while to investigate the subject, I shall merely call your attention to this ancient author's drawing of "An altar organ blown by the agency of a wind-mill." The cylindrical vessel forcing the air into the pipes by means of a piston is here shown.
In our own days, in a journal of only twenty-five years back, we read that "a
