76 



Mr. G. M. Whipple on 



[Feb. 7. 



loudness, but differing markedly in what is called quality or timbre, 

 were alternately sounded, two perfectly distinct figures were obtained, 

 each presenting itself again and again for many alternations the 

 instant its own note was sounded, and remaining constant until that 

 note ceased. By this apparatus, therefore, permanent pictures of the 

 relative quality of musical sounds may be secured. 



I content myself here with a description of the phenomena I have 

 observed, and make no attempt at determining the mechanical condi- 

 tions under which they occur. It may, however, be worth while to 

 remark that the most striking feature of the figures above described, 

 the vortices, can be exactly reproduced with the caoutchouc tube 

 apparatus by gently sucking a little air through it, taking care that the 

 whole opening of the tube is not in simultaneous contact with the lips, 

 and that its other end is not completely closed by the disc and film. 



Before concluding I wish to draw attention to some allied phe- 

 nomena described by Mr. B. B. Tylor in "Nature," for May, 1877, 

 p. 12. Distinct patterns were obtained by him, but it would 

 appear from the directions he gives for producing " a film more free 

 from interference- colours, so as to display the vibration-figures on an 

 almost clear ground" that no permanent colour-patterns are in ques- 

 tion in his letter. He speaks indeed of "the gorgeous scenic effect of 

 the masses of prismatic colour whirled hither and thither by the 

 musical vibrations," but of nothing more fixed and regular. The 

 mode of experimenting adopted by him on that occasion suggested the 

 third form of apparatus described in the present paper. 



February 7, 1878. 



Sir JOSEPH HOOKER, K.C.S.L, President/in the Chair. 



The Presents received were laid on the table and thanks ordered for 

 them. 



The following Papers were read : — 



I. " On the Compaiison of the Standard Barometers of the 

 Royal Observatory, Greenwich, and the Kew Observatory." 

 By G. M. Whipple, B.Sc, Superintendent of the Kew Ob- 

 servatory. Commimicated by order of the Kew Committee, 

 Warren De La Rue, F.R.S., Vice-Chairman. Received 

 November 26, 1877. 



The Standard Barometers of these two important establishments, up 

 to within a recent date, had never been compared directly, although 



