405 



tension and resistance of the vocal ligaments, and on the pressure of 

 the column of air in the trachea. 



3. The grave tones vary directly, and the acute tones inversely, as 

 the vibrating length and tension of the vocal ligaments. 



4. The vocal tube is adjusted to vibrate with the glottis by the 

 combined influence of its variations of length and of tension. 



5. The elevation of the larynx shortens the vocal tube; and its 

 depression produces the contrary effect. The diameter and exten- 

 sion of the tube vary reciprocally with the length. 



6. The falsetto tones are produced by a nodal division of the column 

 of air, together with the vocal tube, into vibrating lengths. 



7. The pitch of the vocal organs, wtien in a state of rest, is, in 

 general, the octave of their fundamental note, 



The paper is illustrated by several drawings. 



8. " Du Son et de l'Electricite." Anonymous, with the signature of 

 Hermes. Being a Prize Essay for the Royal Medal. 



This paper contains the account of a great number of facts and 

 observations, collected from various sources, on the subject of the 

 relations subsisting between electricity, the production of sound, the 

 crystallization of bodies, the transmission of heat, the emission of 

 light, and various atmospheric changes ; from the consideration of 

 which the general conclusion is drawn that all these phenomena are 

 perhaps the results of the undulations of some ponderable material. 



9. " Physiological Remarks on several Muscles of the Upper Ex- 

 tremity." By F. O.Ward, Esq., Medical Student at King's College, 

 London. Communicated by P. M. Roget, M.D., Sec. R.S. 



There is a remarkable fold in the tendon of the pectoralis major 

 muscle, described by all anatomists, but the purpose of which has 

 never yet, as the author believes, been explained. The muscle itself 

 consists of two portions, one smaller and upper, arising from the cla- 

 vicle, and passing downwards and outwards to an insertion in the 

 humerus at a greater distance from the shoulder-joint than the place 

 where the tendon of the larger and lower portion of the muscle, which 

 arises from the sternum and ribs, and has a general direction upwards 

 and outwards, terminates. Thus the respective portions of tendon 

 belonging to the two divisions of the muscle are found to cross each 

 other ; the margin of that proceeding from the lower division passing 

 behind, and appearing above that which proceeds from the upper fibres 

 of the muscle. The forces exerted by each portion of the muscle 

 being thus applied to parts of the bone at different distances from the 

 fulcrum, act with different mechanical powers ; which the author finds 

 in every case to correspond exactly with the variations in the effects 

 required to be produced, under different circumstances, by these mus- 

 cular actions. Those muscular fibres, the tendon of which is inserted 

 nearest to the centre of motion, and which consequently act by a 

 shorter lever, are adapted to motions requiring a less force, but a 

 greater velocity : and such is precisely the mechanical condition of 

 the lower portion of the pectoralis major, which is employed more 



