Five Spectroscopic Binaries.

SX Aurigae.-Spectroscopic observations yield K1 = 172, K2 = 322 km/sec, and the photographic luminosity ratio of the two components, 12/11 = 0.45. These results are combined with Oosterhoff's ac- curate light-curve to obtain values of the masses, radii, and luminosities and estimates of their uncertain- ties. V Puppis.-We find K1 = 199, K2 =342 km/sec, and 12/11=0.57. The value of K1+K2 is significantly smaller than that obtained by Miss Maury. New values of the masses, radii, and luminosities of the corn- ponents are adopted, though the light-curves of Roberts and van Gent are in poor agreement. ~ Centauri.----Here also K1(111 km/sec)+K2(159 km/sec) is smaller than Miss Maury's older deter- mination. An improved value of the period is obtained. RY Scuti.-With the exceptions of X 4026 and X 4088, all strong lines show stationary displacements and originate in a shell. If the variations of the positions of these two lines, which are in phase with Gaposchkin's light-elements, represent orbital motion, the mass of the system is well in excess of 1000. i Bootis B.-WefindK1= 115, K2=231 km/sec, andl2/li~O.6. Aperiod 15X lO7dayslonger than that obtained by Plaut from the photometric data is required to satisfy the spectroscopic observations