g 66 Analyfis of a Stone 



the tympanum, and communicated the impreffions imme- 

 diately to the internal organ. This not happening for fome 

 months after the membrane was deftroyed, probably arofe 

 from the inflammation of the tympanum confining the 

 ftapes, and rendering its vibrations imperfect. 



That founds can be communicated with accuracy by the 

 bones of the fkull to the internal organ, when received from 

 folid or liquid fubftances, has long been well underftood. 



That the membrana tympani is incapable of perfectly 

 anfwering this purpofe, when founds are propagated through 

 air, has been a generally received opinion ; to refute which, 

 was the object of my former paper. That, in cafes in which 

 the membrana tympani has been deftroyed, the air is ca- 

 pable of acting with fufficient force upon the ftapes to com- 

 municate vibrations to it, and to produce on the internal 

 organ the neeeffary effect for perfect hearing, is completely 

 afcertained bv Mr. Cooper's obfervations. 



XIII. Analxfis of a Stone called we Gadolinite ; tvitb an 

 Account of fome of the Properties of the new Earth it 

 contains-. By C. V A uauELi N *. 



1 HE number of fimple bodies, and particularly that of 

 earths, has been greatly increafed within a few years paft; 

 and if chemiftrv go on Mill thus advancing, it is to be appre- 

 hended that the time may arrive when the human mind will 

 not be able to embrace all the combinations produced by the 

 multitude of fimple bodies. 



But the analogy which exifts between certain claffes of 

 natural fubftances, gives chemifts reafon to fufpect that they 

 contain a common generating principle, and affords them a 

 hope that fome fortunate chance, or an experiment made bv 

 fome man of genius, will reduce them all to one fingle kind, 

 either by difengaging them from thofe principles which efta- 

 blifh differences between them, or by combining thefe fame 

 elements to thofe which are fimple. 



* From the Annates de Cblm.e, No. 107. 



Til! 



