The spectra of all stars of the sixth magnitude and brighter will
generally be found upon these plates, except in the case of red stars.
Many fainter blue stars also appear. Three or four exposures are made
upon a single plate. The entire sky north of -24° would be covered
twice, according to this plan, with 180 plates and 690 exposures. It is
found preferable in some cases to make only two exposures; and when the
plate appears to be a poor one, the work is repeated. The number of
plates is therefore increased. Last summer the plates appeared to be
giving poor results. Dust on the prisms seemed to be the explanation of
this difficulty. Many regions were reobserved on this account. The first
cycle, covering the entire sky from zero to twenty-four hours of right
ascension, has been completed.

The work will be finished during the coming year by a second cycle of
observations, which has already been begun. The first cycle contains 257
plates, all of which have been measured, and a large part of the
reduction completed. 8,313 spectra have been measured on them, nearly
all of which have been identified, and the places of a greater portion
of the stars brought forward to the year 1900, and entered in catalogue
form. In the second cycle, 64 plates have been taken, and about as many
more will be required. 51 plates have been measured and identified,
including 2,974 spectra. A study of the photographic brightness and
distribution of the light in the spectra will also be made.

The results will be published in the form of a catalogue resembling the
Photometric Catalogue given in volume xiv. of the Annals of Harvard
College Observatory. It will contain the approximate place of each star
for 1900, its designation, the character of the spectrum as derived from
each of the plates in which it was photographed, the references to these