The daily exchange. [volume] (Baltimore, Md.) 1858-1861, 1858-02-23
IMPORTANT SCIENTIFIC INTELLIGENCE.
We copy the following from the onion of the 10th
instant.
Washington, February IS. 1853.

Washington, February Is, 1853.
SIR: have the honor to communicate to YOU the
result OF the observations specially made by the
United States naval astronomical expedition to de-
termine the solar paraax-the suns distance from
the earth.
1t will be remembered by the department that
DR.. Gerling-an eminent geometer of Germany
suggested the practicability of determining this
fundamental astronomical datum from observations
OF Venus near the inferior conjunction instead of
awaiting the rare phenomena of transits of the
planet across the suns disc; that an expedition to
the southern hemisphere was proposed to the de-
partment by myself for the purpose of making these
observations which. in connection with similar oh
servations to be made at the Naval Observatory
would test the method and that the earnest com
mendatlons of the measure by PHYSICISTS both in
Europe and this country, induced Congress to au-
thorlze the expedition by special grant in the APP
preparation bill approved Sd August lS4S
We were absent from the United States nearly
three and half years, and the observations consti
tuting the more immediate object of the expedition
extended through parts of each of the years from
November, lS49, to September, 1852, inclusive
So many classes of observations were embraced
In the plan of operations adopted by the department
that our small party was almost constantly occu-
pied IN observatory duty proper, and it was not
possible to prepare any of the data for the final
computations until after the return of the expedi-
ton to the United States. Then our first efforts
were to put in proper form for the computer all the
observations of the planets Venus and Mars and the
stars with which they had been compared
Whilst our men of science had been unanimous
IN advocating the organization of an expedition
because of the additional mass of important infor
nation certain to be collected by it, there were
some who entertained opinion that the method
OF determining the parallax proposed by DR.. Ger
ling would not afford result so reliable as had
been derived from the transits of Venus in l76l and
1863.
For obvious reasons, therefore, it was proper that
the discussion OF the result from our observations
should be Entrusted to astronomer thoroughly
competent to appreciate the problem, vet wholly
uncommtted as to the comparative merits of the
two methods.
Under the sanction of the department Dr. B. A.
Could Jr, of Cambridge, Massachusetts was selected
for the purposes and the elaborate refinement with
which he has executed this difficult and delicate
task is ample proof that the confidence of the de-
partment not misplaced. His report does him
great honor. 1t will fill from $50 to l40 pages in
volume Sd of the results of the expedition-the lar
ger portions of it and all the remainder of the vol
ume being already printed.
The result obtained by him for the suns equatorial
horizontal paraUac is 1885, or o. 0762 less than
the value commonly adopted; and he concludes that
we may assume with advantage 81 5000 correspond
ing to assistance for that unary of &c. l60 900 statute
miles,
As the information is of high interest to astrono-
mers, have the honor to suggest that it may be
made known in advance of the publication of the
volume
have the honor to be your obedient servant,
j. NJ GILLIss,
- Superintendent
Hon. l. Toucey,
Secretary Of the Navy.