The notation  hydrated compound ânH2O , where n is the number of water molecules per formula unit of the salt, is commonly used to show that a salt is hydrated. The n is usually a low integer, though it is possible for fractional values to occur. For example, in a monohydrate n is one, and in a hexahydrate n is 6.
When does spring start? How you define the first day of spring depends on whether you follow the astronomical or meteorological seasons. This year, spring will take place between March 20 and June 21, if you use the astronomical method. But it starts slightly earlier, between March 1 and May 31, if you follow the meteorological calendar.
He finally comes up with a solution: Have the wedding on March 21 - the first day of spring!. Unfortunately, if George had gone through with the nuptials (and Seinfeld aficionados know why he never did), he would have been a full day late. You see, in America, spring no longer falls on March 21. In 2005, for instance, the vernal equinox, the first day of spring for the Northern Hemisphere, comes on Sunday, March 20 at 12:33 GMT, or 7:33 a.m. EST (4:33 a.m. PST). Now this doesn't seem right.