I'm partial to dry laid, think it holds up better to time, and have seen, more than a few times, good stonework react violently to being needlessly pointed up with Portland. But if we're gonna throw lime into the mix...

Here's the first of a ten part primer from the Virginia Lime Works - http://www.youtube.com/watch?v=7xBzrjKAsTs&feature=channel

But start with their vid on slaking - http://www.youtube.com/watch?v=eSKX0gzESwI&feature=channel

"We build too many walls and not enough bridges" - Isaac Newton

http://bridgewright.wordpress.com/