This is a Wheeler and Wilson D9 made c. 1900 before Singer took over in 1905. I'm sure Joe will second this but these are fantastic sewing machines though needles and bobbins are a bit of a tough find. Like 10x mentioned they use 127x1 needles and use an obsolete "bagel bobbin". MY1014 needles will work as a replacement though sizes are limited. Shank is too large on a 15x1 needle to use unless the machine has been modified. After Singer took control of W&W they kept making these machine for a couple years and them modified the model to fit in Singer cabinets along with new decals. In 1913 the Singer 9W was replaced with the 115 which was also a Rotary.
Jon