Newtonian Forms for Dilaton Spacetimes in String Theory

We show that the Newtonian forms for the motion of particles in mechanics and for light in geometrical optics can be extend to the Gibbons-Meada and the Garfinkle-Horne dilaton spacetimes in string theory. As an example, we study the bending of the light rays, the perihelion advance of a planet, and the radar echo delay in the dilaton spacetimes. The results show that the gravitational effects arising from the dilaton can be observed provided that the dilaton is large enough.