  Using atomic hydrogen (HI) data from the VLA Galactic Plane Survey we measure
the HI terminal velocity as a function of longitude for the first quadrant of
the Milky Way. We use these data, together with our previous work on the fourth
Galactic quadrant, to produce a densely sampled, uniformly measured, rotation
curve of the Northern and Southern Milky Way between $3~{\rm kpc} < R < 8~{\rm
kpc}$. We determine a new joint rotation curve fit for the first and fourth
quadrants, which is consistent with the fit we published in McClure-Griffiths
\& Dickey (2007) and can be used for estimating kinematic distances interior to
the solar circle. Structure in the rotation curves is now exquisitely well
defined, showing significant velocity structure on lengths of $\sim 200$ pc,
which is much greater than the spatial resolution of the rotation curve.
Furthermore, the shape of the rotation curves for the first and fourth
quadrants, even after subtraction of a circular rotation fit shows a surprising
degree of correlation with a roughly sinusoidal pattern between $4.2 < R < 7$
kpc.
