PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 505 



former meeting, in regard to currents of heated air beinof caused 

 to ascend by the superior gravity of the colder particles, and that 

 respiration was due to the outer colder air forcing the heated air 

 out. Respiration is mainly due to the muscles, and is no part of a 

 movement that we can control, and is, in part, under control of 

 the will. The air rushes in, not because it is cold, but because 

 there is a place for it to go in. The air rushes in, whether hot or 

 cold. This he supposes to be the true theory. The main object 

 of ventilation is for respiration, and it matters very little what 

 kind of apparatus are used for getting rid of this carbonic acid 

 gas. The great trouble is, to get rid of the odors of various 

 kinds, both natural and artificial. Persons are aifected by odors 

 in various ways; for instance, musk is exceedingly difficult for 

 some to breathe, and to others it is very pleasant. To some, the 

 odor of the rose has been known to produce fainting. Some per- 

 sons cannot remain in a room where this odor is. The necessity 

 of ventilation, and the kind, difiers for many persons. The Doctor 

 himself, slept with indifference whether the windows were open 

 or shut; he felt just the same with them either way. He remem- 

 bered how very particular the doctor with whom he studied med- 

 icine was, in regard to having fregh air; and on no account hardly 

 could he be induced to sleep in a room unless there were four 

 windows to it, so that he might constantly inhale fresh air. 



Mr. R. C. Overton stated that, when at the oil regions last win- 

 ter, the place where he had to sleep was a compartment seven 

 feet long, three feet wide and three feet high, made of pine 

 boards. The only ventilation to it was by the cracks between 

 each board. He did not, however, feel uncomfortable while 

 sleeping there. This statement excited some expressions of sur- 

 prise, if not incredulity; but this case is explained by the action 

 of diffusion. 



Dr. L. Bradley said, that the process of breathing is entirely 

 muscular, and is not much under the influence of the will. When 

 a person feels chilly, he holds his breath; they do the same when 

 they are frightened, and this causes fainting. If a person, when 

 chilly or frightened, instead of forgetting to breathe or holding 

 their breath, if they will only give a few respirations, they will 

 not faint. Mr. Henry T. Callo joined in the discussion, and denied 

 some of the positions taken by several previous speakers. 



Mr. Norman Wiard transmitted to the Association the following; 



