8 REPORT OF THE SECRETARY. 
for the particular class of work in view, has been received, and was the 
last of the principal pieces of apparatus (provided for from the Smith- 
sonian fund) to be putin place. The outfit is now in the main com- 
plete. : 
This country has no observatory devoted exclusively to astro-physical 
research, though England, France, and Germany have maintained for 
a number of years at a considerable expense observatories for the study 
of the physical condition of celestial bodies. I therefore indulged 
the hope that, in presenting the matter to Congress as previously re- 
ported, a request for a small annual appropriation for the maintenance 
of the observatory thus founded and equipped might meet with favor- 
able consideration. I may say that the amount asked for ($10,000 for 
annual maintenance) has been appropriated, and will be available dur- 
ing the coming fiscal year. 
In adjusting and determining the constants of the instruments, a work 
involving considerable labor, I have had the valuable assistance of Prof. 
C. ©. Hutchins, of Bowdoin College, during a portion of the summer 
vacation. No permanent appointments of the assistants who will be 
required to carry on the investigations contemplated will be made until 
after the appropriation shall have become available. 
EXPLORATIONS. 
The explorations of chief importance carried on by the Institution 
have been conducted by the Bureau of Ethnology and by the National 
Museum, and to the reports of these departments reference should be 
made for details. 
PUBLICATIONS. 
The publications for the year have continued to represent the usual 
standard both in the number and in the general character of the sey- 
eral issues. 
Smithsonian Contributions to Knowledge.—Mention may be made here 
of a publication embracing a collection of twenty-three colored plates 
illustrating the forest trees of North America, an unfinished work un- 
dertaken by the late Dr. Asa Gray, many years ago, which although in 
the quarto form of the Contributions to Knowledge, will not be in- 
cluded in volumes of that series. While no memoir has been actually 
published during the year, a paper presenting an account of some new 
experiments in aero-dynamies (already referred to) is in course of prep- 
aration, and will probably be through the pressin Augnst. It will not 
much exceed 100 quarto pages of letterpress, and will be illustrated by 
about ten plates. 
Smithsonian Miscellaneous Collections.—A memoir on ‘The Corrections 
of Sextants for errors of Eccentricity and Gravitation,” by Mr. Joseph 
A. Rogers, of this city, presents a good discussion of the subject, and 
has a practical as well as a theoretical value. A “ Bibliography of the 
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