32 
referred to that the apostrophe should be used 
to indicate an omitted 18, never an omitted 19. 
It then occurred to me that a comma might be 
similarly used to denote the omission of 19; 
but there seemed to be such important objec- 
tions to this, that I dismissed the matter without 
further thought until, a few weeks ago, I re- 
ceived a letter from Mr. R. Pearl of the Uni- 
versity of Michigan, in which he urged the 
desirability of adopting some method of abbre- 
viation, and suggested the use of a period. 
There are, however, quite as serious objections 
to a period as toacomma. After some corre- 
spondence on the matter it has seemed to both 
of us that the colon so used would afford the 
best solution to the problem; but in order to 
avail ourselves of other possible suggestions, 
we desire to call attention to the matter in 
SCIENCE. 
The signs hitherto considered and some of 
the more obvious objections to them are the 
following: The comma would be objectionable 
because in almost every citation two commas— 
one for punctuation, the other to mark the 
elision—would be brought together, and no 
proof-reader could be expected to accustom 
himself to the anomaly; thus in a recent publi- 
cation, if the dates had been 1993, etc., instead 
of 1898, etc., the use of the comma would have 
given this undesirable result: ‘‘In Anurida, 
as in Orthoptera (Wheeler, ,93; Heymons, 
,95) and Lepisma (Heymons, ,97*), ete.’’? The 
period is so commonly used as a decimal point, 
that .98 or .97°, for example, would be mislead- 
ing. It would clearly be of some advantage to 
have a character that should stand, like the 
apostrophe, on a line with the tops of the 
figures; but the various signs which usually 
have that position, as the asterisk, obelisk, etc., 
have such a fixed usage, as a means of referring 
to footnotes, that it seems unwise to employ 
any of them for this purpose. An “inverted 
period would be open to the objection that a 
defective apostrophe could not be distinguished 
from it. The dash takes up too much room; 
the hyphen, though shorter, is not better in this 
respect than the colon, and has the disadvan- 
tage that, in the case of papers occupying more 
than a single year in publication, it now has to 
serve for omitted digits which might, or might 
SCIENCE. 
[N.S. Vou. XIII, No. 314. 
not, be the figures 19, for which we should 
wish it invariably to stand. 
So far as I recall, there is only one usage, 
except that of ordinary punctuation, to which 
the colon has been put that would be liable to 
interfere with its use for the purpose contem- 
plated here. It has been used to separate the 
number designating a volume from that desig- 
nating the first page of an article in that volume 
—a substitute for the letter p. Since in the 
proposed usage the colon would stand between 
the name of the author cited (not a number) 
and the last two figures of the year in which 
his paper was published, I think no ambi- 
guity could arise. If, however, serious objec- 
tions to the use the colon, or a better plan, 
occurs to any one interested in the matter, 
both Mr. Pearl and the writer would be glad 
to profit by suggestions communicated through 
SCIENCE or directly. BE. L. Mark. 
HARVARD UNIVERSITY, 
December 13, 1900. 
ASTRONOMISCHER JAHRESBERICHT. 
EAcH year there is being issued under the 
editorship of Professor Dr. W. Wislicenus, from 
the press of Georg Reimer, an Astronomischer 
Jahresbericht, or annual review of all kinds of 
astronomical publications, including writings on 
geodesy and navigation if not too remotely con- 
nected with astronomy. This work is carried 
on under the supervision of the Astronomische 
Gesellschaft. The first volume contains the 
publications of 1899, and consists of xxiv + 537 
pages, 8vo. This was issued in the spring of 
1900. 
In the interests of publishers, of readers and 
of the nation which he represents, the associate- 
editor for the United States desires to make the 
compilation and review of American publica- 
tions on the above named subjects as complete 
as possible. To this end he invites authors and 
publishers to favor him with the title and place 
of publication of each book or article issued 
during 1901 and each subsequent year or a 
copy of the same if convenient that it may be 
reviewed for this purpose. The reviews are 
merely explanatory—unot critical. 
HERMAN 8S. Davis. 
INTERNATIONAL LATITUDE OBSERVATORY 
GAITHERSBURG, MARYLAND. 
