PROBLEMS IN ASTROMETRY: The present status of double star astronomy

. A general survey has been made of the present status of double star astronomy in regard to discoveries of new pairs, the measurements of relative and absolute motions of known pairs, as well as their magnitudes and radial velocities. It is proposed that more emphasis should be placed on obtaining photographic observations of the wider pairs. The visual observers should be allowed the facilities of large refractors and reflectors for the difficult pairs most in need of ob- servations. Further progress in the field also depends upon accurate data on parallaxes, mass ratios, magnitudes, spectral types and radial velocities.