WARMING AND VENTILATION. 327 



more, in order ttat this stage-veiitilation may not interfere with that of 

 the body of the house, it is necessary to connect the two systems with 

 each other. 



For this purpose, a chimney or an auxiliary ventilating-flue should be 

 made above the stage and joined with the main chimney, the draught 

 of which should be increased by means of gas-jets lighted at the propel 

 time, a little while before the smoke is produced. 



129. Precautions to be taken to prevent re-entry of the external air on the 

 stage. — The introduction of external cold air on the stage should also be 

 avoided, in order that currents from the stage to the hall may not be 

 produced, which would be disagreeable both ro the actors and to the 

 audience. This result has taken place at the Theatre du Cirque, where 

 large openings in direct communication with a court and public way 

 have not been closed. 



130. Lighting -a2Jparatiis for the auditorium. — Without wishing to spec- 

 ify here the arrangements to be adopted for lighting theaters, we will 

 confine ourselves to stating that glass ceilings, which require to 

 be ornamented with colored designs, occasion a considerable loss of 

 light, while they produce in the room an amount of heat very unpleasant 

 for the spectators in the upper tiers, and which is also very expensive 

 for the directors, who are naturally led unduly to restrict the number 

 of gas-jets, thus rendering useless the expense gone to in introducing 

 this method of illumination. Although this consumption, even when 

 thus restricted, assists the removal of foul air, the amount carried off 

 is seldom more than 450 cubic feet to a cubic foot of gas burned, while 

 with suitable arrangements the amount of GOOtoSOOcubic feetof airmight 

 be carried off to every cubic foot of gas. 



131. Arrangements to hemade to secure and regulate the amount of warmth 

 and ventilation. — Warmtti and ventilation can only be properly secured 

 by an attentive observation of atmospheric conditions and of the num- 

 ber of spectators, and by prompt application of the proper means. There 

 is, in fact, no difficulty in the arrangement or the management of the 

 apparatus; but it is necessary to take care, and not to trust to ordinary 

 firemen, nor even to the managers of theaters, always interested iu 

 using as little coal and gas as possible. 



It is then indispensable to confide this trust to special agents, respon- 

 sible directly for the authority and the regularity of the service, and 

 obliged to make daily reports. Without such control, independent of 

 theatrical managers, the best apparatus may give imperfect results or 

 even fail entirely. 



132. Application. — The preceding rules have been adopted, after long 

 discussion and many experiments,* to serve as bases for the plans to 

 be adopted at the Lyric Theater and the Chatelet Theater. The city 



* The commission charged with the investigatiou of the question and the examina- 

 tion of projects was composed of Dumas, member of the Institute, president ; Chais- 

 d'Est-Ange, Pelouso, Rayer, Gilbert, Caristie, Baltard, General Morin, members of the 

 Institute; Grassi, chemist. 



