C++: Rethrowing exceptions

Consider the following piece of code

catch (Base& w)
{
...
throw;
}
catch (Base& w)
{
...
throw w;
}

What do you think is the difference between the 2 approaches above .

In the first case , the exception is re thrown . In the second case a copy is made and a new exception is thrown . Also the copy is based on the static type i.e
Base (copy constructor is called )