MOUNT WILSON SOLAR OBSERVATORY. 1 73 



(8) An attempt to detect the Zeeman effect caused by the general mag- 

 netic field of the sun gives promising results. 



(9) A working hypothesis of sun-spots has been developed as a guide to 

 further research. 



(10) A new and more accurate determination has been made of the cor- 

 rection to observed magnitudes which depends upon the distances of stars 

 from the axis of the 60-inch reflector. 



(11) An independent determination of the magnitude scale of the North 

 Polar Sequence gives results in excellent agreement with those of Pickering 

 from magnitude 10.5 to 15.5. For fainter stars there is some divergence, 

 which is still under investigation. 



(12) Photographs of the Algol variable RR Draconis show this star to be 

 of unusual interest because of its great range of variation, which extends 

 from magnitude 9.70 to 13.50. 



(13) Visual and photographic observations of Mars, made with the 60- 

 inch reflector, give no evidence of the existence of a geometrical system of 

 straight "canals." 



( 14) About 850 photographs of stellar spectra, taken with the Cassegrain 

 spectrograph, have yielded the radial velocities of about 250 stars. 



(15) About 45 new spectroscopic binaries have been discovered, and 

 many other suspected cases are under observation. 



(16) The star Lalande 15290 has been found to have the largest appar- 

 ently constant radial velocity hitherto observed ( — 248 km. per second). 



(17) A study of the remarkable new star in Gemini indicates a constant 

 radial velocity of about +10 km. per second, a marked resemblance of its 

 spectrum to that of certain Wolf-Rayet stars, the probable presence of the 

 nitrogen lines, and no marked evidence of radium. The star passed through 

 the series of changes characteristic of Nova. 



(18) A classification of 453 stellar spectra, based upon about 1,500 spec- 

 trograms obtained with the 60-inch reflector, gives results in good agreement 

 with the Harvard classification. Some interesting new subdivisions have 

 been found. 



(19) Stars with strong enhanced lines seem to have a greater absolute 

 luminosity than those in which these lines are fainter. 



(20) In eleven cases of composite spectra belonging to spectroscopic 

 binaries, the spectrum of the brighter component is always of the earlier 

 type. 



(21) Photographs of the integrated spectrum of certain regions of the 

 Milky Way indicate that the greater part of its light probably comes from 

 solar stars. 



(22) A new determination has been made of the velocities of the helium 

 stars of Stream I and the A stars of Streams I and II, and the positions of 

 the vertices have been greatly improved. 



(23) Certain helium stars have been found which apparently belong to 

 Stream II. 



