Question

Fresh grass does n 't catch fire easily but dry grass catches fire easily ? Why?

Answer 1

 Green leaves have moisture in them . But in dried leaf the cells are dead and it is combustible to fire. 

Answer 2

answer:

I know one foundry that has been burnt four times by this means ; and many foundries, for this reason, have given up grinding their coal. What makes this material most dangerous is, it takes fire very easily from a strong spark when fine and dry, but does not show itself for several hours, and sometimes days after.