192 LABORATORY LESSONS IN GENERAL SCIENCE 



This difference, amounting at different times of year to 

 values varying from seconds to about 16 minutes, is the 

 "equation of time " (or the "sun fast," "sun slow") of the 

 almanacs. It must be taken into account in comparing 

 clock time and sun time. Clock or "local" noon is deter- 

 mined from true noon by adding (or subtracting) the equa- 

 tion of time for what particular date ? 



10. What is true of noon local time for you and for places 

 (a) eastward; (6) westward? What will be true of the 



STANDARD TIME IN THE UNITED STATES 



FIG. 85. 



watch readings of people keeping local time in towns east 

 and west of one another ? What is meant by standard time ? 

 With the sun neither slow nor fast, by what amount will a 

 clock that keeps standard time vary from the true local 

 time? 



