lioyal Society. 533 



traces all the several changes which the traciiefe and spiracles undergo 

 dtiring their transformations ; describing particularly the successive 

 development of the air vesicles in connexion with the power of flight. 

 The system of muscles, both of inspiration and of expiration, is mi- 

 nutely detailed, and their various modes of action examined. He 

 next investigates the series of nerves appropriated to the exercise of 

 the respiratory function, and establishes a distinction in the offices of 

 these nerves, corresponding to the sources from which tliey derive 

 their origin, and presenting remarkable analogies with similar distinc- 

 tions in tlie nerves of vertebrate animals. The manner in which re- 

 spiration is performed, and the phsenomena presented with regard to 

 this function under various circumstances, such as submersion, and 

 confinement in unrespirable or deleterious gases, are next considered. 

 An account is then given of a series of experiments made with a view 

 to determine the quantity of oxygen consumed, and of carbonic acid 

 produced, by the respiration of various kinds of insects in different 

 states, from which tlie conclusion is drawn that the quantity of air 

 deteriorated is governed by several circumstances not necessarily con- 

 nected with the natural habits of the species. When the insect is in 

 its pupa state, and in complete hybernation, its respiration is at its 

 minimum of energy : and, on the contrary, it is at its maximum when 

 the insect is in the imago state, and in the condition of greatest ac- 

 tivity. 



In the concluding section of the paper the author institutes an in- 

 quiry into the capabilities which insects possess of supporting life, 

 during longer or shorter periods, when immersed in different media j 

 and gives a tabular view of the results of numerous experiments which 

 he made on this subject. It appears from these observations that the 

 order in which these media possess the power of extinguishing vitality 

 is the following : viz. hydrogen, water, carbonic acid, nitrous acid 

 gas, chlorine, and cyanogen. Some of these agents, however, affect 

 respiration much more rapidly than others, which, though their action 

 is sloiver, are eventually more fatal to the insect. 



6. " Demonstration de I'egalite a deux droits de la somme des 

 angles d'un triangle quelconque, independamment de la theorie des 

 paralleles, et de la consideration de I'infini." Par M. Paulet, de Ge- 

 neve. Communicated by P. M. Roget, iVI.D., Sec. R.S. 



Tlie author demonstrates the equality of the sum of the angles of 

 a triangle to two right angles, by the aid of a preliminary theorem, 

 of which the following is the enunciation. A straight line forming an 

 acute angle with another straight line, will, when sufficiently produced, 

 meet any line, perpendicular to the latter, and situated on the side 

 of the acute angle. 



7. " Experimental Researches into the Physiology of the Human 

 Voice." liy John Bishop, Esq. Communicated by P. M. Roget, M.D., 

 Sec. R.S.* 



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

 Hermes. Being a Prize Essay for the Royal Medal. 



* Mr. Bishop's paper will be found in the present volume, at p. 201 ci&i'q. 



