If you’re one of history’s greatest electrical inventors, it is only suitable to have stationery that’s equal to your stature.
The central image is of the unfinished Wardenclyffe Tower; other inventions pictured include the oscillation transformer, steam-and-gas turbine and a telautomaton (that is, a remote-controlled device; this one is a boat).
Found via (where else?) Letterheady.com, an archive of interesting letterheads.