1S06.] 



Proceedings of Learned Societies. 



S43 



came nearly ftationary, and on (hoie at 

 Canton the barometer had little tendency 

 to the equatropical motirns through the 

 months of Oilober and November. Ob- 

 fervations fimilar to the foregoing were 

 made from this time till the arrival of the 

 /hip in the Margate roads, which went to 

 the confirmation and eflablifhment of the 

 fame fafls. 



Another curious paper laid before the 

 Royal Society reiates to the " Differences 

 in the Magnetic Needle on board his Ma- 

 jefty's fhip the InveiHgator, arifing from 

 an alteration in the direction of the Ship's 

 Head." In this Captain Flinders in- 

 fers, —r. That there was a difference in 

 the direiSlion of the magnetic needle when 

 the (hip's head pointed to the eaft, and 

 when it was direfted nellward. — 2. That 

 this difference was eafterly when the (liip's 

 head wa» weft, and weftcrly when it was 

 eaft. — 3. That when the Ihip's head was 

 north or fouth, the needle took the fame 

 dire6lion or nearly (o that it would on 

 fti'ire, and fliewed a variation from the 

 true meridian. — 4-. That the error in va- 

 riation was nearly proportionate to the 

 number of pointi which the (hip's head 

 was from north or fouth. Hence the Cap- 

 tain fuppofes, I. An attraflive power of 

 the different bodies in a (hip, which are 

 eapabie ef afFe6f ing the compafs, to be col- 

 le(5fing- into fomething like a focal point 

 or center of gravity, and this point is 

 nearly in the center of the (hip where the 

 iron (hit a:e depofited. 2. He (iippofcs 

 this point to be endued with the fame kind 

 of attraflion as the pole of the hemifphere 

 where the (hip is : confequently, in New 

 Holland the Ibuth end of the needle would 

 be attraffed by it, and the north end re- 

 pelled. 3. That the attraflive power of 

 this point is (ufficiently Ihong in a fhip of 

 war to interfVre with the aition of the 

 magnetic poles upon a compafs placed 

 Up in or in the binnacle. 



Captain Flinders in the courfe of tKjs 

 paper has given feveral tables, the infer- 

 ence from which is, that the variation is 

 moie weiierly when taken upon the binna- 

 cle uf a (liip whofe head is weftward in 

 north lat., than when obferved in the cen- 

 ter of the (hip. He thinks it will be 

 found, that the variation of the compai* 

 it cr.-atcr when going down the EnglKh 

 Chiiiiiel, than when when coming up it, 

 an 1 then it will follow that from a high 

 fouih latitude where the diffcrencet are 

 grcar on one (ide, they are moft likely to 

 dcceale gra.lua.ly to the equator, and 'o 

 iATCalC m tie lame v/a^tu a hi^h north 



latitude, where they are great on the 

 other iide. 



In Mr. Carlisle's paper on " The 

 Phyliology of the Stapes, one of the bones 

 of the organ of hearing : deduced from a 

 comparative view of its (fru6lure and iii'es 

 in different animals j" it is affumed that 

 the whole organ of hearing is an appara- 

 tus to colledl occurring founds, and to 

 convey' them to the feat of that peculiar 

 fenfation, regulating their intenlity, of 

 facilitating their progrefs, according to the 

 degree of i.mpetus ; and that in ihele 

 relpefts the ear refembks the eye. 



The oflicula auditia* in man, and in 

 the mammalia, form a feries of conduc- 

 tors, through which founds are tranfmit- 

 ted from the menihrana tympani ir/to the 

 fenlitive parts of the or^an. The num- 

 btr, forms, and relative junflions of thefe 

 oilicles are vaii )us but, in all cafes, 

 their office feems limited to the convey- 

 ance of (bunds received through the me- 

 dium of the air ; becnufe fiflics have 

 no parts correfjionding with them. In two 

 claffes of :uiinials, the aves, and amphibia 

 ofLiNN^us, one bjne in the fiiuation 

 of the ftapes is the only cfiicle of the 

 tympanum : in all other animals, it ts 

 placed next to the feat of (enfible impref- 

 lion, and molt remote from that part of 

 the organ on which founds fir.t impinge. 

 Next follow delcriptions of the parts or 

 the ear in the human and various other 

 luhjsff : and as a nutural confequencs- 

 Mi-. C.s fays, "It feems that ail the muf- 

 cles of tiie ofTicula audi iis are of the in- 

 voluntary kind, and the ftimulus to their 

 ailion is found. The chorda tympani, 

 which fupplies them, is a gangliated 

 nerve : if this fuppofition be tiue, thea 

 the mufcles fhuulJ be confiJered as all 

 adting together, and it is well known that 

 perlon* who heir imperfeflly are more 

 fcnflble to founds in a noify place, as if the 

 mufcles were by that means awakened to 

 ai^.tion, 



'" The office which the balls of the 

 (tapes holds, and which the (tapedens 

 mufele is efpecially dcflined lo perform, 

 feems to throw confidcrable light on the 

 ufe of the cochlea. It cannot be aIlowe4 

 (hat the preffure of the watery fluid in the 

 labyrinth is a requifiie condition 10 pro- 

 duce (he fenfstioij of hearing, fince all 

 biids h<ar without any mechanifm for 

 thatpurpjfe, but as fuch predure mult 

 ultimately give increafed tenfion to the 

 fciitftra cochleae, it fol.owg that we en- 

 tpiire at this part Lr the prii.cipal ufe of 

 the (tapes. 



