IMPROVEMENTS IN THEATER SANITATION. 89 



increased temperature in the flues. It becomes necessary to adopt 

 mechanical means of ventilation by using either exhaust fans or 

 pressure blowers or both, these being driven either by steam en- 

 gines or by electric motors. In the older theaters, which were 

 lighted by gas, the heat of the flames could be utilized to a certain 

 extent in creating ascending currents in outlet shafts, and this 

 accomplished some air renewal. But nowadays the central chan- 

 delier is almost entirely dispensed with; glowing carbon lamps, fed 

 by electric currents, replace the gas flames; hence mechanical 

 ventilation seems all the more indicated. 



Two principal methods of theater ventilation may be arranged : 

 in one the fresh air enters at or near the floor and rises upward to 

 the ceiling, to be removed by suitable outlet flues; in this method 

 the incoming air follows the naturally existing air currents; in the 

 other method pure air enters at the top through perforated cor- 

 nices or holes in the ceiling, and gradually descends, to be removed 

 by outlets located at or near the floor line. The two systems are 

 known as the "upward" and the "downward" systems; each of 

 them has been successfully tried, each offers some advantages, and 

 each has its advocates. In both systems separate means for sup- 

 plying fresh air to the boxes, balconies, and galleries are required. 

 Owing to the different opinions held by architects and engineers, 

 the two systems have often been made the subject of inquiry by 

 scientific and government commissions in France, England, Ger- 

 many, and the United States. 



A French scientist, Darcet, was the first to suggest a scientific 

 system of theater ventilation. He made use of the heat from the 

 central chandelier for removing the foul air, and admitted the air 

 through numerous openings in the floor and through inlets in the 

 front of the boxes. 



Dr. Reid, an English specialist in ventilation, is generally re- 

 garded as the originator of the upward method in ventilation. He 

 applied the same with some success to the ventilation of the Houses 

 of Parliament in London. Here fresh air is drawn in from high 

 towers, and is conducted to the basement, where it is sprayed and 

 moistened. A part of the air is warmed by hot-water coils in a 

 sub-basement, while part remains cold. The warm and the cold 

 air are mixed in special mixing chambers. From here the tem- 

 pered air goes to a chamber located directly under the floor of 

 the auditorium, and passes into the hall at the floor level through 

 numerous small holes in the floor. The air enters with low velocity, 

 and to prevent unpleasant draughts the floor is covered in one 

 hall with hair carpet and in the other with coarse hemp matting, 

 both of which are cleaned every ^ay. The removal of the foul 



VOL. LTI. — 8 



