The Human Ear

It wonlíi itppeajr tfiat all our hearing is dunu in ;i vcry i ■■ onder water, as shown by the following extract from n London paper : "Professor Tyndall concluded ono of .Iris recent lecturea by giving a. minuto desoription of the human eiw. Hecxplaini'l huw the externa] orifico 8f the eur is olosed it the botton by a circular tympaïiio moiiibrane, behind whioh is :t oavity known as the "drum;" the drom issepi aratedfrom thebrain by two orífices, Uw onc round and the other oval. The ifices are closed by fine möiubraües. Across tlu; cavity of the driun Btrótcftea ii sorics of four littlu boTies, ono of whioh aota as a hammei andanotber asan anvill Behind the baay partition, wiiidi is picreed by the lv"o orífices aLready m ntionnd, is the extraordinary organ oalled the labyrinth, fllled with the water ; Üúa organ is betweOn tKc partition and tlio brain, and over its lining ineni'brane tho torminal íllbrii -s oí the auditory in: ure distributed. Xhere is bh appaxatns in.sidc the labyriuth adnyrably adaptod td raspend to these vibrations of tlie water whioh oorresponds to the rates of vibration of cbrtain " brisÜes," of which the sui'l apparatus connists. Finally, {here is iu the libyrintli a wondurful ovgau, disoovered by the Márchese Corti, whioh is, to all appearance, a musical instrument: with ita corda so stretched as to iiceejjt vfbsationa of difierent periods, and trans-i mit thcm to aerve filamento whish traTérsè (In: prgAn. "Witliin the -rs of imn, and without tlujir knowlodo or contrivancc, tliia lulo af tlircu thousand stringa has existod for ages, accêptintj' ihe musio of the outer woiW and rendcring it fit for reoi'ption ljy the braïn. Kae)i nnisical tremor which falla u;jii tliisorgan sclocts from its tonsioned fibres tho ono appropriato to its own jiitoli, and throws that fibre iuto uaisonant ribration. Au 1 tliusno matter how oomplicated the motion of tlic external air niay be, these microscopio strings can analyze it and roveal tlie constituents of whioh it is composcd ; at loast such are tlic present views of tlioso authorities who best under.stand th( apparattzs Which transmití sonorous vibrations to tlio auditory norve."