Grandfather clauses were designed to

The intent and effect of such rules was to prevent African-American former slaves and their descendants from voting, but without denying poor and illiterate whites the right to vote.

Explanation:

basically to stop blacks from voting without having to hard themselves like the white people have not meet the age requirement, but their father was a civil war hero for south, they they were allowed to vote.

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation:

george kidding