What always amazes me is that these people-without having any modern instrument and not knowing the true nature of atoms and bonding- did great job in preparing, analyzing and quantifying their findings. I don't think I can do the same today. They also had to explain all the details and (just like today) the chemistry had to be reproducible. Look at Zeise's paper that was 46 pages long. I can't even imagine how much work went to that research.
Another interesting thing that I learned from this paper is that ethylene was called "olefiant gas" in 1794!
And finally, I was able to find who really called it "organometallic" compounds. It was Sir Edward Frankland who coined the term. Here we can see how smart he was to understand the importance of these compounds :
I suggest everyone who calls himself an organometallic or inorganic chemist should read this article.
"...procured cannot fail to cause its employment for a great variety of transformations in organic compounds"