Page:Popular Science Monthly Volume 91.djvu/270

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��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.

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