318 



part in producing the wonderful qualities of modulation and expres- 

 sion peculiar to the human voice. In animated conversation, decla- 

 mation and singing, this may be seen. 



" Its function then appears to be threefold rendering the slack, 

 mobile and flexible vocal organ or tube rigid, tense and inflexible, 

 and fit to produce pure tone ; by its bulk and density acting as a 

 loader and strengthener, making the tone more sonorous, full and 

 deep, and thus compensating for want of length and size in the 

 organ ; and finally, by its varying shape, bulk, density and pressure, 

 furnishing an important aid in producing the inimitable qualities of 

 modulation and expression enjoyed by the human voice. 



" That it is a part of the organ of voice and an important accessory 

 in giving it perfection, may be inferred also from its situation on the 

 larynx and trachea, and its being supplied by the same nerves its 

 being largest in man, where the voice and speech are perfect its 

 being proportionally larger in women and children than in men, 

 their smaller and more mobile organs requiring its peculiar aid. 

 Among the lower animals, it is present (at least in a fully developed 

 condition) only in the Mammalia, but among them there is a remark- 

 able exception in the Cetacea they have it not, and they have no 

 voice. In Birds, which have such great power and modulation of 

 voice, the structure of the vocal organ and tube is different from that 

 in man, and sufficient in itself to produce these qualities. 



" The importance of the thyroid body must be admitted when it is 

 shown to be necessary for the perfection of the voice, and hence of 

 speech that great and indispensable agent in the cultivating and 

 advancing the highest faculties of man." 



II. "Experimental Researches on the Strength of Pillars of 

 Cast Iron." By EATON HODGKINSON, Esq., F.R.S., Pro- 

 fessor of the Mechanical Principles of Engineering, Uni- 

 versity College, London. Received November 20, 1856. 



(Abstract.) 



In a previous paper on this subject (Philosophical Transactions, 

 1840), I had shown, 1st, that a long circular pillar, with its 



