Show STAI TIKE TIMM AND SUN TIME the aitay binti oat out from t 10 star stars cherl vi lien it Is noon tho the time for sending out tho tile noon signal from washington is tho the instant tho the sun crosses the seventy fifth meridian this however Js is not tho the sun bun which gives us light and heat beat but an invisible imaginary one because foi certain reasons the true sun does not ere cross the tile meri meridian diall at tile same moment every day but during ono one part of the year he lie gets over it at little mora more ahead of time each day and during the pat pait t he lie is correspond correspondingly ing ly behind time and so this fictitious sun is used be cause its apparent path around tile ea earth rth brings it exactly over tho the same line ile at the same moment every day lay now at just what instant this sun crosses the tile meridian is determined by means of the stars for time at tho the observatory is not reckoned by the sun but by the stars every clear nigh tan astronomer at the observatory looks through a largo large telescope for certain stars which lie knows must cross a certain line at certain t times I 1 mea and by the use of an electrical mac machine aline ho lie makes a record of the time each star passes as shown by a clock which ice keeps eps sidereal or star time lie ile then consults a printed table which shows him at just what time each star must have passed and by as much as this timo time differs from fron that recorded by the clock the tile latter is wrong and in that way tho tile sidereal clock is regulated this star timo time is then reduced to sun time which requires some calculation as there is a difference between tho the two of about four minutes each day these two clocks the tho one keeping stai stat time and the oilier other sun time are of very fine quality and aro are as near perfection as possible although they cannot help being affected by changes of tem temperature pera and different conditions of tho the atmosphere mo sphere they very rarely are more than a fractional part of a second out of the way no attempt is ever made to correct such errors but they aro are carefully noted and allowed for in mak making I 1 ng calculations for the purpose of distributing time a third clock known as a transmitter is 13 used this is set to keep ciulo by the tile seventy fifth meridian and is regulated by the standard clock before mentioned it is in all respects similar to the other clocks except that it has lim attached to it an all ingenious device by which an electric circuit may bo be alternately opened and closed with each beat of the pendulum clifford howard in ladies homo llomo journal |