Most post offices will close at noon July 3rd but this will not affect regular mail delivery. July 4th is the federal holiday and post offices will be closed with no mail delivery.
20th May would be a Sunday.
Well this year May 3, 2010 is a Monday. So yes there is school.
3 quarts is 6 pints6 pints is 12 cups3 quarts is 12 cups
1863 see http://www.usps.com/postalhistory/_pdf/DeliveryMondaythroughSaturday.pdf#search='saturday mail delivery'