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parts at once, and with the eyes directed to the chest, the relation of 

 the movements and of the sounds, normal or abnormal, of this most 

 important organ is very fully and satisfactorily made out. 



POSTSCRIPT. Received April 22, 1858. 



In connexion with that part of my paper which treats of the re- 

 striction of hearing to the closed ear, I desire to add the fact which 

 I have ascertained within the last few days, that if one ear be closed 

 wholly or partially at its external part, i. e. at the meatus externus, by 

 disease or by congenital malformation, while the other ear is healthy, 

 the sound of the tuning-fork, applied to any part of the head, is 

 heard only in the closed ear. This fact holds, although the closed 

 ear is totally unaffected by sounds conveyed through the external air. 



I have further to mention the fact, that all persons, deaf in one ear, 

 whom I have lately examined, with one exception, hear the sound of 

 the tuning-fork applied to the head in that ear only that is deaf to 

 external sounds. A man who has been totally deaf in one ear for 

 thirty years, in consequence of a violent blow upon the head, had the 

 tuning-fork applied over the forehead. He started, and said that he 

 heard only in the ear which had been deaf during that long course of 

 time. In such cases I have been disposed to believe that, amidst other 

 lesions of the organ of hearing, there may be present an obstruction 

 or closure, that a reverberation takes place, and that thus a restriction 

 of hearing is secured for the diseased organ. 



II. "On the Stratification of Vesicular Ice by Pressure." By 

 Professor WILLIAM THOMSON, F.R.S. In a Letter to 

 Professor STOKES, Sec. R.S. Received April 3, 1858. 



In my last letter to you I pointed out that my brother's theory pf 

 the effect of pressure in lowering the freezing-point of water, affords 

 a perfect explanation of various remarkable phenomena involving 

 the internal melting of ice, described by Professor Tyndall in the 

 Number of the ' Proceedings ' which has just been published. I 

 wish now to show that the stratification of vesicular ice by pressure 

 observed on a large scale in glaciers, and the lamination of clear ice 

 described by Dr. Tyndall as produced in hand specimens by a 



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