Simplify the following text for a Grade 8 native English-speaking person.
Original: In Alaska , the change took place when Friday , 6 October 1867 was followed again by Friday , 18 October after the US purchase of Alaska from Russia , which was still on the Julian calendar .
Simplified: In Alaska , Friday , October 6 , 1867 was followed by Friday , October 18 1867 . The day was still called Friday because when the US bought Alaska from Russia , the International Date Line was changed when the Gregorian calendar was adopted .