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INTERNATIONAL ASTRONOMICAL UNION Proc. N. A. S. 
to the fact that the gradual increase in color with increasing magnitude 
makes it difficult to distinguish the influence of the color equation of the 
instrument from that of an error in the scale. 
The visual and photovisual standards now available also require further 
attention. These will most conveniently be considered in connection with 
the photographic standards. 
When once it is clear that all serious systematic errors have been elim- 
inated, the committee may with propriety consider the combination of the 
results of the different investigations for the formation of series of inter- 
national standards, which doubtless would then require revision only at 
infrequent intervals. 
It would be a convenience to observers if the adopted values were re- 
ferred to alternative systems of color: in the case of photographic magni- 
tudes, for example, to the color system of an average objective, say, that 
of the 8-inch Draper telescope which is essentially that of the Harvard 
Polar Sequence, and also to the color system of the reflector, which very 
likely is constant or nearly so for all instruments of this type. The visual 
standards should be referred to the color system of the Harvard Photom- 
etry; but photovisual standards based on the reflector should also be avail- 
able. The standardization of a plate and filter for use with the reflector 
may not prove feasible; but having chosen an isochromatic plate which 
is easily obtainable it doubtless would not prove too difficult to construct 
a filter such that the combination reproduces the adopted standards. Be- 
cause of its bearing upon various physical questions such as stellar tem- 
peratures, the spectral intensity-curves corresponding to the color-system 
used should in all cases be published. 
2. Reduction of the magnitudes of the Carte du Ciel to the normal scale. — 
This undertaking has been in the hands of the Committee on Magnitudes 
of the Carte du Ciel. In case the work of this committee is merged with 
that of the organization under discussion, the investigation will immediately 
become one of the most important and pressing questions before the newly 
organized committee. 
Two methods of procedure are possible: (a) Await the results of (1) 
above, and then use the resulting standards ; {h) establish the scale for the 
Astrographic Zones with the aid of the valuable counts recently published 
by Turner. This would require a knowledge of the star-density as a func- 
tion of galactic latitude and longitude for each interval of magnitude. 
Each of these methods has its advantages and disadvantages which will 
require the attention of the committee. 
3. Nomenclature of newly discovered variable stars. — Hitherto in the 
hands of the Astronomische Gesellschaft. An important question of 
policy must be faced in this connection. Probably the Argelander nota- 
tion should be continued, because of its convenience. For catalogue 
purposes, however, the Harvard notation has important advantages, be- 
