The years 1700, 1800 and 1900 were

The years 1700, 1800 and 1900 were not leap years. A normal year is defined as 365 days. Putting all of these rules together, you can see that a year is a leap year not only if it is divisible by 4, it also has to be divisible by 400 if it is a centurial year. So 1700, 1800 and 1900 were not leap years.