CHAPTER VI. 



Science anb practice. 



" I always find theoretical men rather inclined to look with a 

 certain amount of disdain upon practical men, and to think that 

 practical men know nothing about their subject unless they follow 

 the dictates of theorists. But they are now paying much more 

 attention to the teachings of experience." W. H. Preece, F.fi.S. 



THE proper ventilation of public buildings is a matter in 

 which we are all personally interested; for who has not 

 suffered at some time or another from the polluted and 

 poisonous atmosphere which is usually found in every church, 

 hall, or theatre in the kingdom 1 ? It is true that many 

 efforts have been made to remedy this deplorable state of 

 things, but from one cause or another they have generally 

 proved abortive. 



To show, however, that it is not impossible to effectually 

 ventilate a large building, we may mention a striking 

 instance in the case of the London Custom House, 

 the bad ventilation of which was long notorious; indeed, 

 so far back as thirty years ago, when a Royal Commission, 

 composed of the most eminent scientific and practical men 



