Helen B. Sawyer A Bibliography of Individual Globular Clusters

394 Publications of the David Dunlap Observatory
therein. For some of the longer works this has been a rather diffi-
cult procedure. For Shapley's Star Clusters and his article Stellar
Clusters in the Handbuch der Astrophysik, which provide such a
comprehensive summary of information, only material not pre-
viously published by the same author has been indexed.
In cases where the same author has published more than one
paper in a given year, these are differentiated by an italicized Roman
numeral following the year. A long series of papers forming an
obvious whole, such as that of Bigourdan, has been indexed under
the first year of the series with a dash following the date, i.e., 1891
Bigourdan. Certain volumes which appeared in several editions
such as Webb, Celestial Objects for Common Telescopes, have been
indexed under the date of the edition which I used, with a cross
reference to the date of the first edition. The titles of Shaplex s
two series, Studies of Color and Magnitude in Stellar Clusters, in
Mt. Wilson Communications, and Studies of Magnitudes in Star
Clusters, in Mt. Wilson Contributions, have been condensed simply
to Studies. Readers will find convenient access to the papers of
three famous astronomers in the collected volumes of their work, as
follows: The Scientific Papers of Sir William Herschel, 2 vols.,
London, 1912; The Scientific Papers of William Parsons, Third Earl
of Rosce, London, 1926; The Scientific Papers of Sir William
Huggins, London, 1909.
The abbreviations employed have been selected to combine
minimum printing space with maximum ease of identification for
the reader. Certain abbreviations, such as M.\. , A.N.,
etc., arc
so well-known in astronomical literature as to cause no confusion.
Abbreviations for other periodicals have been constructed in accord-
ance with principles from the I.A.U. Transactions, vol. Ill, pp.
19-39, 1928, in conjunction with the Union List of Serials. The
latter list has been used extensively in locating the whereabouts on
this continent of many of the rarer volumes.
In general the word Observatory has been omitted from the
abbreviation, and taken as understood. Where publications are
from academies or societies, however, this is always indicated. For
most publications the abbreviation has been chosen for ease of
locating the reference in the Union List; that is, the place of publi-
cation appears first, followed by the series, such as bulletin, circular,
etc. We might note that the publication Comptes Rendus is to be