625 



The author next investigates the acoustic relations between the 

 actions of the glottis and that of the vocal pipe, and the acoustic 

 effects of flexible membranous tubes on a column of air vibrating 

 within it, and finds that the structure of the trachea and of the soft 

 parts above and below the larynx is adapted to vibrate synchro- 

 nously with any note that may be formed in the larynx. The fal- 

 setto voice may be produced either by the partial closing of the 

 glottis, or by a nodal division of the vocal chords ; the pitch of the 

 sound in the production of this peculiar modification of the voice, 

 being such that the column of air in the vocal tube is of the precise 

 length requisite to vibrate in unison with the larynx. The inquiry is 

 further extended to the sources of the various tones of the voice 

 in singing, such as the bass, tenor, contralto, and soprano ; together 

 with their subdivisions of barytone, mezzo-soprano, and soprano- 

 sfogato ; and to the places which they occupy in the musical scale, 

 independently of the falsetto, the compass of the natural voice 

 rarely exceeds two octaves ; although in some cases, as in those of 

 Malibran and Catalani, it may extend even beyond three. The 

 voice in singing is modulated by the contraction or relaxation of 

 the velum, uvula and fauces. The author lastly adverts to the at- 

 tempts that have, at various times, been made by the Abbe Mical, 

 Faber, Kratzenstein, De Kempelin, Willis, Wheatstone and others, 

 to imitate articulate sounds by mechanism. 



Having thus examined the human voice as resulting from the 

 vibration of membranous ligaments, in obedience, first, to the laws 

 of musical strings ; secondly, to those of reeded instruments ; and 

 thirdly, to those of membranous pipes ; he arrives at the conclusion, 

 that the vocal organs combine, in reality, the actions of each of 

 these instruments, and exhibit in conjunction, the perfect type of 

 every one of them. 



June 18, 1846. 



The MARQUIS OF NORTHAMPTON, President, in the Chair. 



" The Electric Fluid." By W. F. Stevenson, Esq., F.R.S. 



The author denies the existence of two electric fluids, and main- 

 tains that all the phenomena are explicable on the hypothesis of a 

 single fluid ; which when present in a conducting body renders it 

 positive, and in a non-conducting body, negative ; but a body which 

 is naturally a conductor, may, he asserts, be rendered otherwise, by 

 changing its form. 



" Observations of the Heights of the Thermometer and Barometer 

 made at Lenham Lodge, near Maidstone, Kent, during the first nine 

 days of the month of June 1846." By George Hunsley Fieldino^, 

 M.D., F.R.S. 



On Sunday the 7th of June 1846, the thermometer in the shade 

 rose to the extraordinary height of 94° Fahr-, exceeding by one de- 



