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We present three-dimensional kinematics of Sagittarius (Sgr) trailing tidaldebris in six fields located 70-130 degrees along the stream from the Sgr dwarfgalaxy core. The data are from our proper-motion (PM) survey of Kapteyn'sSelected Areas, in which we have measured accurate PMs to faint magnitudes in40x40 arcmin fields evenly spaced across the sky. The radial velocity (RV)signature of Sgr has been identified among our follow-up spectroscopic data infour of the six fields and combined with mean PMs ofspectroscopically-confirmed members to derive space motions of Sgr debris basedon 15-64 confirmed stream members per field. These kinematics are compared topredictions of the Law & Majewski (2010) model of Sgr disruption; we findreasonable agreement with model predictions in RVs and PMs along Galacticlatitude. However, an upward adjustment of the Local Standard of Rest velocityTheta_LSR from its standard 220 km/s to at least $232\pm14$ km/s (and possiblyas high as $264\pm23$ km/s) is necessary to bring 3-D model debris kinematicsand our measurements into agreement. Satisfactory model fits thatsimultaneously reproduce known position, distance, and radial velocity trendsof the Sgr tidal streams, while significantly increasing Theta_LSR}, could onlybe achieved by increasing the Galactic bulge and disk mass while leaving thedark matter halo fixed to the best-fit values from Law & Majewski (2010). Wederive low-resolution spectroscopic abundances along this stretch of the Sgrstream and find a constant [Fe/H] = -1.15 (with ~0.5 dex scatter in each field-- typical for dwarf galaxy populations) among the four fields with reliablemeasurements. A constant metallicity suggests that debris along the ~60-degreespan of this study was all stripped from Sgr on the same orbital passage.

Kinematics and Chemistry of Stars Along the Sagittarius Trailing Tidal Tail and Constraints on the Milky Way Mass Distribution