Kircher's Speaking-Trumpet.
"The Musurgia," printed in 1650, gives an account of a speaking-trumpet invented by Kircher. From a convent situated on the top of a mountain, he assembled twelve hundred persons to divine service, and read the litany to them through the trumpet, at a distance of from two to five Italian miles. Soon after a tube was made, according to Kircher's directions, by which words, without elevating the voice, could be understood from Ebersdorf to Neugeben.