I found a free manual download for this machine at, of all places,
http://www.singer.com ! If the link below doesn't work, go there and click on "customer support" and then on "instruction manuals" and enter 1919 in the search. It will come up with w1919 which is the White machine! Maybe that model was made by Singer??? Anyway, here is the link I found:
http://www.singerco.com/accessories/manuals.html . You need Adobe Acrobat to download. It downloads as a PDF which can then be printed out.
I did a search through the manual but did not find anything referencing dropping the feed dogs. As I mentioned before, I would look for a knob (at the base of the machine, usually around the stitch selection column) or a lever (in the bobbin area, with the bobbin cover open) with the teeth mark logo on it.