than 2500 geographical square miles, or within a space extending from Melfi to Lagonegro, north and south, and from Duchessa to Monte Peloso, east and west.
The narratives of those situated towards the northern and southern extremities of the sound area, all described what they had heard, as a low, grating, heavy, sighing rush, of twenty to sixty seconds in duration, some thinking that it was also a sort of rumbling sound, but with none, a distinct, well-defined explosion, or several in succession.
Those who were situated towards the middle of the sound area, and towards its east and west boundaries, on the contrary, very generally described the sound, as something of the same character as to tone, but with more rumbling, using the words "rombo, rumore di carozzo," &c., more, and such as "fischio, sospiramente," &c., less; and as shorter and more abrupt, both in commencement and ending, and in duration.
These descriptions, aided by the expressive gesticulation and imitative powers of the narrators, conveyed a far more exact notion of the sounds heard, and of the relative times in which they were heard, than I can hope to transmit in writing. They were collected in my progress, and as they may be referred to in the narrative, without much idea of their leading to any very distinct or valuable conclusion. The result however now appears to support the conclusions arrived at, from the rigid methods of tracing the origin out from the wave-paths, in a manner as remarkable as it is satisfactory.
It will be seen that our wave-path lines on the surface, although they mainly point to one great focal point, do not do so absolutely, some pointing to an extreme centre,
