254 



Popular Science Monthly 



Mr. Harold Edel, 

 Managing Director 

 of the Strand Thea- 

 ter, New York city, 

 attending to busi- 

 ness in his office 

 and following the 

 progress of the show 

 at the same time. 

 At right is shown 

 the details of the 

 electrical devices by 

 means of which the 

 director can keep 

 in touch with the 

 stage and audience 



Directing a Motion Picture Show 

 From the Manager's Office 



THE problem of keeping in touch with 

 the audience and the stage while 

 attending to the affairs of his own 

 private office, has been solved 

 in a very Twentieth Century 

 way by Mr. Harold Edel, 

 managing director of the 

 Strand Theater, New York 

 City. He sits in his office 

 physically; he sits with 

 the crowd electrically. 



A detectagraph leads from 

 the footlights of the stage to 

 a loud-speaking receiver 

 mounted in a box on 

 the manager's desk. 

 This transmitter is like 

 the concealed tele- 

 phone instrument by 

 means of which detec- 

 tives listen to the con- 

 versations of criminals. 

 By the throwing of a 



switch, the director can hear the 

 orchestra and the soloists as 

 well as if he were one of the 

 audience. 



When a certain motion picture 

 is scheduled on the screen, the 

 director connects up the 

 speedometer near him with die 

 motion picture projector in the 

 gallery. This meter is similar 

 to those used on automobiles, 

 except that it indicates feet of 

 film per second instead of miles 

 per hour. Hence, the director 

 instantly can find out when the 

 operator fails to run his picture 

 at the proper speed. The opera- 

 tor can then expect 

 to hear from the 

 d i rec tor — who 

 merely speaks into 

 the telephone trans- 

 mitter mounted in 

 the same box as the 

 detectaphone re- 

 ceiver. By means 

 of this same trans- 

 mitter the director 

 can get in touch 

 with any part of his 

 theater when giving 

 his orders to "ginger 

 up" the show. 



The waterworks of the clock depend 

 upon the evaporation of the water 

 and the expansion of the ether vapor 



The Evaporation of Water Drives This 

 Remarkable Clock 



A CLOCK designed by M. Bernardi, a 

 German watchmaker, is run by ether 

 and water. The driving wheel 

 consists of three glass tubes 

 having light glass balls fused 

 to their ends. Some ether 

 vapor is contained in each 

 tube system. The water is 

 contained in a reservoir, 

 through which the balls 

 pass when turning. 



An outside covering of 

 cloth on the balls carries 

 up a film of water when the 

 balls turn out of the reser- 

 voir. When water begins 

 to evaporate the tempera- 

 ture lowers. This lowers 

 the pressure within the 

 upper balls. The ether 

 vapor in the lower balls 

 rises upward as each cooled 

 ball rises. 



