The Montgomery advertiser., 1909-06-06

from there the time Is sent up and down the Pacific coast, just as it is from here to the Eastern part of the United States. In the cities where the central time is used the flash marks II Eo'clock. An hour later the local opera tors drop the time balls.
 The mean time Is determined by as- tfomical observations. When certain stars pass the 75th meridian. called the meridian of Washingtoh, it is eer- tain time. The operator watches for the stars through a telescope. the Held of which is covered with fine wires.
 As the stars reach certain point in transit the operator presses a key in his hand. A contact is made and re- corded on a chronostaph. The chrono@ graph consists of cylinder covered with paper. A fountain pen rests on the paper. It is held by an arm at- taehed to the mechanism. The cylin- der revolves once a minute and the pen moves along the surface of the paper. making a spiral line.
 A sidereal clock of the finest make Is running in a vault underneath the ob- servatory, With each tick of the clock there Is a contact of two points. These two points are attached to wires that lead to an electro-magnet attached to the arm that holds the pen of tlfe chronograph. The clock is so adjusted that each minute the pen is made to jump to one side, consequently there is a break In the line.
 There are other breaks, too. when the observer watches the stars cross the lines in the field of the telescope. The mean times thus recorded for each star after being corrected for errors, is the clock time of the stars transit. whatever difference there is between, this clock time and the sidereal time marked by the transit of the stars is the error of the clock. From these as- tronomical observations the 'sidereal time is obtained. The error amounts to but little, rarely being more than from i've one-hundredths to ten one- hundredths of a second.
 The sidereal clocks are wonderful pieces of work. They we're made in Berlin by a man named Riefer. There are two of the clocks in the observa- tory building here. and third Rieher clock is in the room from which the time is sent out to the world.
 Tho sidereaI clocks in the observa- tory are beneath the ground, In the basement of the building. The room which contains them is small. There are three walls surrounding it. with space between them. The effort is n1GGe LO keep In0 t6tupoE0tuEC WiLuih the room always the same. For this purpose there Is a 'thermostat. so deli cately made that the increase In heat caused by the presence of a human be- ing in the room. if only for 6 minute. will be indicated.
 The clocks are in large glass cyIin- ders, four or five feet high and heFmst- Ically sealed. The cylinders are fast ened to stone pillars which reach down Into the ground and do not touch any part of the flooring. Thus there is no chance of vibrations affecting the clock. except from beyond the control of the scientists.
 The clock winds itself every thirty seconds by means of a small weight. The fail of the weight moves the clock. When the weight reaches a certain point a small electro-magnet becomes operative, and the weight Is picked up to start on its downward course again. giving enough power to keep the clock going.
 There are two clocks which may be nsSd in automatically sendIng out the time. 60 if one should break down the other could be ready for emergency. These clociss are made accurate by coaaparison wish the sidereai clocks.
 The time of sending q flash over the wires Is practically notilng. At one