70 Professor Faraday [Feb. 25, 



be material, an absolute test is procured at once ; for, as has been 

 already explained, no sound will be heard in one ear, and a full sound 

 will be heard in the other. For example, a musical box placed upon 

 the banks of the Serpentine, is heard in that ear which is supplied with 

 that limb of the stethophone (an elongated one) whose cup is immersed 

 in the river, and not at all in that connected with that limb whose cup 

 is held upon the ground. In the same way this test of restriction of 

 hearing to one ear, or of uno-aural hearing, is available for deciding 

 upon the comparative acoustic value of different arrangements. If 

 we desire for instance to know whether surrounding a glass with 

 water and another with air, both filled with water and previously 

 being equal in communicating sound to the stethophone, gives a 

 difference of sound, the fact is immediately made known. The ear 

 connected with the limb of the stethoscope immersed in the glass 

 surrounded with water hears nothing, while the ear connected with the 

 glass surrounded with air has a distinct sensation. 



[8. S. A.] 



WEEKLY EVENING MEETING, 



Friday, February 26, 1859. 



H.R.H. The Prince Consort, KG. D.C.L. F.R.S. 

 Vice-Patron, in the Chair. 



Professor Faraday, D.C.L. F.R,S. 

 On Schojiheiri' s Ozone and Antozone, 



Ozone has already been before the members of the Royal Institution on 

 two occasions: on the 18th June 1851, when Schonbein's early views 

 of it were given, and on the 10th June 1853, when the results of 

 MM. Fremy and E. Becquerel, obtained by passing the electric spark 

 through dry oxygen, were described ; and also the opinion of Schonbein 

 respecting the entrance of ozone as such (and not as simple oxygen) 

 into combination. Since then, Schonbein has been led to the belief 

 that oxygen can exist in a third state, as far removed by its properties 

 from ordinary oxygen in the one direction as ozone is in the other ; 

 and therefore, in a certain sense antagonistic to ozone. This substance 

 he names antozone, and believes that it also enters into combination, 

 retaining, for the time, its special properties. Hence there is not 

 merely ozone and antozone, but also ozonide and antozonide compounds. 

 Thus, permanganic acid, chromic acid, peroxides of manganese, lead. 



