Darby on Post-Millenialism

I have been following DyspraxicFundamentalist for a while reading his Darby quotes. We grew up on Darby but I don't remember reading much of his Collected Writings myself. So here is a question put to me that I cannot answer. Is there an online archive of his Collected Writings. I have seen the Synopsis of the Bible online, but not the rest. Help appreciated.

Let me ask you a question: you seem to know John Nelson Darby's works very well. I remember reading somewhere an essay by him in which he attacked the idea of Christian moral suasion being used to reform a whole community. I think his point was to show the absurdity of the post-millennial idea of a truly Christian world. I remember it was very well argued. Do you have a web-source for it?