The problem with Google Books, though, is that their algorithms suck. I typed in the following search phrase:
"Robert D. Kohn" "H. Black & Co."
I got 10 hits back. Variations on the ampersand and "company" abbreviation did not help. Typing in
"Robert D. Kohn" Black factory
turned up more than 100 hits. Almost all of them including the phrase "H. Black & Co." It seems that Google Books either can't search for the term "H. Black & Co." in the poorly scanned images (but can search for the term "Robert D. Kohn", amazingly), or that Google Books has a crappy search algorithm that truncated my search results because Google thinks it knows better than I what I'm looking for.