Note 309 — PART II.
Reading edition
De Humboldt speaks of these rocks on the shores of the Oronoco. Travellers have heard from time to time subterraneous sounds proceed from them at sunrise, resembling those of an organ. He believes in the existence of this mysterious music, although not fortunate enough to have heard it himself; and thinks that it may be produced by currents of air issuing through the crevices.