874 Scientific Intelligence. — Geology. 



9. On 'Subterraneous and Ominous Sounds. — In a former 

 volume of the Journal, we communicated some curious details 

 in regard to what have been called subterranean and ominous 

 sounds. Sir John Herschell has lately considered this subject, 

 and conjectures that the noises of Nakoos, in Arabia, may be 

 owing to a subterraneous production of steam, by the generation 

 and condensation of which, under certain circumstances, sounds 

 are well known to be produced. They belong to the same class 

 of phenomena as the combustion of a jet of hydrogen gas in 

 glass tubes. He also remarks, that wherever extensive subter- 

 raneous caverns exist, communicating with each other, or widi 

 the atmosphere, by means of small orifices, considerable diffe- 

 rences of temperature may occasion currents of air to pass 

 through those apertures with sufficient velocity for producing 

 sonorous vibrations. The sounds described by Humboldt, as 

 heard at sunrise, by those who sleep on certain granitic rocks, 

 on the banks of the Orinoco, may be explained on this principle. 

 The sounds produced at sunrise, by the statue of Memnon, and 

 the twang, like the breaking of a string, heard by the French 

 naturalists to proceed from a granite mountain at Carnac, are 

 viewed by him as referable to a different cause, viz. to pyrome- 

 tric expansions and contractions of the heterogeneous material 

 of which the statue and mountain consist. Similar sounds, and 

 from the same cause, are emitted when heat is applied to any 

 connected mass of machinery ; and the snapping often heard in 

 the bars of a grate affords a familiar example of this phenomenon. 

 Th(e fpllowing amusing account of an ominous sound is given by 

 Gairdner in his book on the " Music of Nature :" — In one of 

 the baronial castles of the north, which has been uninhabited for 

 years, there were heard at times such extraordinary noises, as to 

 confirm the opinion among the country people that the place 

 was haunted. In the western tower an old couple were per- 

 mitted to live, who had been in the service of the former lord, but 

 so imbued were they with the superstitions of the country, that 

 . they never went to bed without expecting to hear the cries of 

 the disturbed spirits of the mansion. An old story was current, 

 that an heir-apparent had been murdered by an uncle, that he 

 might possess the estate, who, however, after enjoying it for a 

 time, was so annoyed by the sounds iii the castle, that he re- 

 tired with an uneasy conscience from the domain, and died in 



