Organ-pipes of Unusual Shapes

Abstract

THROUGH the kindness of Prof. W. B. Morton I have been enabled to examine Robert Gerhardt's original inaugural-dissertation on the Rohrflote, delivered at Halle in 1884. His equation for the case of a pipe with closed chimney is identical with that given by Principal Aldis (NATURE, Aug. 30) for the Bicylindron, and for the Rohrflöte proper with open chimney his equation is the same as mine. Gerhardt discovered a little of the history of this interesting pipe register. The Rohrflote is apparently of con-siderable antiquity. Praetorius mentioned it in his “Syntagma Musicum” (1619), and the pipe was probably invented in the middle of the sixteenth century. Praetorius describes the position of the chimney as being wholly outside, half inside, or wholly inside, of which he recommends the last as offering the greatest protection to the chimney.