 Brown developed this into large high-voltage capacitors that would produce a tiny propulsive force causing the capacitor to jump in one direction when the power was turned on.In 1929 Brown published "How I Control Gravitation," in "Science and Invention" where he claimed the capacitors were producing a mysterious force that interacted with the pull of gravity.He envisions a future where, if his device could be scaled up, "Multi-impulse gravitators weighing hundreds of tons may propel the ocean liners of the future" or even "fantastic 'space cars'" to Mars.