Key points are not available for this paper at this time.
The spectral characteristics, velocity-curves, and spectrographic orbital elements are given for SS Librae, TJIJ Ophiuchi, W Scuti, RZ Draconis, U Scuti, QY Aquilae, VW Cygni, AQ Pegasi, XX Cephei, WW Andromedae, and XY Cephei. Two stars, VW Cyg and AQ Peg, have bright H lines during principal eclipse, and these undergo eclipses as in RW Persei and several other stars
Otto Struve (Tue,) studied this question.