Wow.... cool machine. Yes, it's a long bobbin machine. Can't tell without seeing a picture of the whole head/face... if it's 3/4 size or full sized. I would check out the ISMACS website, to look at dates, which machines were manufactured when in the Singer lineup. Being that old, it's not the 'newer' Vibrating Shuttle machine, has to be earlier than that with a S/N dating to 1898.
The Sphinx decals were very popular and used on a lot of different Singers. It's interesting to me, that the feet are side clampers, it's got the bobbin winder mech. low down on the pillar, add on motor for sure. Awesome spoke wheel.
I'd say you found a beauty. And like someone else said, treadle her. Also, post some more pics if you can.... that show the whole machine?