NATURAL PHILOSOPHY. 179 



great rajiiclity, and at several miles distance. The sounds are 

 made to produce a perfect and distinct language, as intelligible to 

 the natives as that uttered by the human voice. The instrument 

 is in universal practice about the Cameroons, and up in the inte- 

 rior, in the Abo and Budi countries, a part of Central Africa not 

 yet visited by Europeans. " In visiting this part of Africa in 1859, 

 my coming was generally announced beforehand to the different 

 villages by the ' Elliembic' I questioned some of the oldest in- 

 habitants as to the inventor ; but none of them could tell me further 

 than that they supposed ' it must have been some of their great- 

 grandfathers.' This ' Elliembic,' therefore (which is a most in- 

 genious invention), must have been in existence in Africa before 

 telegraphs were dreamed of in England." — Mb. Innes, in Athe- 

 nceum, October, 18G5. 



ACOUSTIC PHENOMENA. 



Prof. Page, of Washington, to whom we are indebted for the 

 curious observations that a bar, when magnetized, emits a musi- 

 cal sound, has recently published a paper on the cause of the 

 unpleasant jingle sometimes heard in pianofortes and other 

 stringed musical instruments. It frequently happens that an in- 

 strument is partly taken to pieces, and searched for some loose 

 screw or fragment of foreign matter which may have fallen ou 

 the wires, but without success. Prof. Page shows, however, 

 that, in most cases, the noise is not in the instrument at all, but 

 is reall}'^ due to the sympathetic vibrations of some object in the 

 apartment, — often a loose pane of glass. He gives an account 

 of a piano, two notes of which had an intolerable jingle. "The 

 room was very small, and while I continued to strike one of these 

 notes, Mr. W. went about the room touching everything witli his 

 finger, and at last he touched a pane of glass in the window near 

 the piano, and the jingling ceased at once. On removing his 

 finger it recommenced. On applying the finger-nail very deli- 

 cately to the pane, it was found to vibrate, and on approaching 

 the ear it was heard distinctly to give out the precise sound of the 

 note on the piano." The pane was wedged up, and search made 

 for the confederate of the other jingling note, which was found 

 to be a loose pane in another window. It often hapjiens that the 

 jingle is transferred to different notes without any apjoarent cause. 

 This is explained by variations in the tension of the objects in the 

 apartment, caused either by a difference in the temperature, or an 

 alteration in the arrangement of the furniture. This explanation 

 of a very common and very irritating phenomenon appears to us 

 to be extremely ingenious. It may be objected, that the sound 

 cannot come from anywhere else but from the piano ; but the ear 

 is remarkably defective in the power of judging of the orighi and 

 direction of sounds, as is shown by the extraordinary effects pi'o- 

 duced by a clever ventriloquist. 



Sondhauss (" Pogg. Ann.," March, 1865) details some experi- 

 ments on the sounds produced by water flowing through orifices 

 in plates cemented at the bottom of upright tubes, in order to 

 compare the resulting musical tones with those produced by a 



