Subject: How did Cannizarro use use Avogardo's Principle to determine atomic mass?

Everywhere I look I find that Avogadro's "equal volumes have equal number of 
molecules" stated and Cannizaro used that to help determine atomic mass. 
Students have asked me how "Avogadro's number" was determined. More interesting 
is how it was first proposed. the reasoning behind it. ANd how were atomic 
masses first determined by Cannizarro? Can you tie all this together in a 
simple way that my high school Science History class will "get it." I found 
Cannizarro's 3 part paper online that explained how he did this, but it was 
frankly so specific and detailed that we simply don't comprehend his procedure. 
Please help us. 

Re: How did Cannizarro use use Avogardo's Principle to determine atomic mass?