492 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



American Institute Polytechnic Association, ] 

 March 26, 1863. j 



The Chairman, S. D. Tillman, Esq., presiding. 



Mr. Bull. — Mr. Chairman, some few weeks ag-o we had some interesting 

 experiments before us, exhibiting a new system of ventilation, and in con- 

 nection with this subject, and merely as a matter of interest during the 

 hour devoted to miscellaneous business, I will read an extract somewhat 

 relating to that subject, as follows: 



"ventilation. 



" The French Academy of Sciences, at a late meeting, listened to a 

 paper from M. Delbruck, which, if well founded, will upset a good many 

 of our existing notioUvS about ventilation. Mr. Delbruck has made some 

 researches on the quantity of air required for breathing during sleep. It 

 strikes him as singular that, while all medical men are unanimous in pre- 

 scribing several cubic meters of pure air for each person sleeping in a 

 room, as absolutely indispensable for health, all animals appear to shun 

 the open air as much as possible, in order to compose themselves to sleep. 

 Thus, the lion and tiger retire to some dark cavern, where the air is con- 

 fined; the dog goes to his kennel and thrusts his snout under his belly; 

 birds, to which the open air would appear to be a necessity, whether 

 asleep or awake, retire to some private corner, and put their heads under 

 their wings. Nay, what does the schoolboy do when left in a dormitory 

 aired with particular care ? If he finds he cannot fall asleep, the first 

 thing he does is to bury his liead under the bed-clothes. Hence, M. Del- 

 bruck concludes that if, when awake, we exhale a quantity of carbonic 

 acid, we must inhale a certain quantity of this gas during sleep, just as 

 plants exhale by day the oxygen they absorb during the night." 



Mr. Rowell. — I have read of experiments where a sparrow lived in a 

 cubic foot of air for three hours, but if taken out after being in one hour, 

 and then placed in again, it would die in a few minutes. 



The Theory of the Wave. 



Mr. Bull read the following extract on the theory of the wave: 

 " The velocity of waves has relation to their magnitude. Some large 

 waves proceed at the rate of from thirty to forty miles an hour. It is a 

 vulgar belief that the water itself advances with the speed of the wave; 

 but in fact the form only advances, while the substance, except a little 

 spray above, remains rising and falling in the same place, according to 

 the laws of the pendulum. A wave of water in this respect is exactly imi- 

 tated by the wave running along a stretched rope when one end of it is 

 shaken; or by the mimic waves of our theaters, which are generally the 

 undulations of long pieces of carpet, moved by attendants. But when a 

 wave reaches a shallow bank or beach, the water becomes really progres- 

 sive, because then, as it cannot sink directly downwards, it falls over and 

 forwards, seeking its level. So awful is the spectacle of a storm at sea, 

 that it is generally viewed through a medium which biases the judgment, 

 and lofty as waves really are, imagination makes them loftier still. No 

 wave rises more than ten feet above the ordinary level, which, with the 

 ten feet that its surface afterwards descends below this, gives twenty feet 



