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INTERNATIONAL ASTRONOMICAL UNION Proc. N. A. S. 
letters at present employed to denote certain characteristics are not used 
in the same sense in different spectral classes. 
The remaining recommendations explain themselves, and all the recom- 
mendations have received the unanimous approval of the members of the 
Committee, either during preliminary discussion, or in their final form. 
H N. RussEJLL, Chairman, W. S. Adams, A. J. Cannon, R. H. Curtiss. 
REPORT OF THE COMMITTEE ON RADIAL VELOCITIES 
We beg to recommend to the American Section of the International 
Astronomical Union: 
1. The formation of a Committee on Radial Velocities, in the Interna- 
tional Astronomical Union, whose duty it shall be to encourage and pro- 
mote research in this field. 
2. There should be cooperation among radial velocity observers to 
the ends that duplication may be limited to necessary and desirable de- 
grees, that the resources of the various observatories may be applied chiefly 
to those problems for which they are the more uniquely adapted, and that 
the accumulation of accurate and homogeneous results may be expedited. 
It is not proposed that the individuality of investigators, as to selection 
of problems and methods, be interfered with, even by suggestion, but only 
that the evident advantages of cooperation be available to all qualified 
observers who seek them. 
3. A Committee of the American Astronomical Society, embracing 
the leading radial velocity observers, or their representatives, in 1910-11 
gave careful consideration to the proposal that radial velocity determina- 
tions should be extended to several thousand stars in the Harvard Re- 
vised Photometry fainter than those previously observed for this purpose, 
on the basis of cooperative division of effort. All of the members but one 
were of the opinion that, however strongly they might desire to engage 
in the suggested cooperative plan, their telescopic resources were too weak 
to give promise of coping successfully with many additional stars. In 
the meantime a 60-inch and a 73-inch reflecting telescope have engaged 
heavily in this work, and other great reflectors are under construction or 
nearing completion. We are of the opinion that cooperation is now prac- 
ticable and desirable. We recommend that those institutions engaged 
extensively in measuring the radial velocities of stars should endeavor so 
to coordinate their programs that the work of determining the radial ve- 
locities of the stars in Boss's Preliminary General Catalogue shall be 
divided amongst them on the basis of their latitudes, the light gathering 
powers of their telescopes, etc. 
4. The present situation in the Southern Hemisphere closely resembles 
that in the Northern Hemisphere in the year 1910. The intensive use 
of very large reflecting telescopes in the Northern Hemisphere will soon 
leave radial velocity determinations in the southern sky far behind, and 
