REPORT ON ASTRONOMY. 
153 
markable conclusion, that the Moon is not homogeneous, and 
has not the form which it would have, had it been originally fluid. 
In 1813, Lindenau published Tables of Mercury. They were 
founded principally on a discussion of 17 transits over the sun’s 
disk. Lindenau concluded from these that a considerable in¬ 
crease of the mass of Venus was necessary to reconcile theory 
with observation. The Tables for perturbations are arranged 
on Carlini’s system. 
In 1810, Lindenau published Tables of Venus. They are 
founded entirely on Bradley’s observations, and on continental 
observations of the present century, with the three observed 
transits. Lindenau would doubtless have preferred a continuous 
series of observations made at Greenwich, but the observation 
of Venus has been almost entirely neglected there. The secu¬ 
lar variations of the orbit deduced from these observations do 
not agree with those given by Laplace’s (or Lagrange’s) theory; 
and Lindenau thinks that the mass of Mercury ought to be 
much increased. In Zach’s Correspondance , vol. 13, Plana as¬ 
serts that this difficulty is at present insuperable. Olbers 
(. Monat. Corr. vol. 22,) prefers the theoretical variations. I 
may mention that it appears from my comparison of observations 
with the Berlin Bphemeris , that these Tables admit of sensible 
improvement. These Tables of Venus (and Bouvard’s of Jupi¬ 
ter,) were compared with late Greenwich observations, by order 
of the English Board of Longitude. In 1811, Reboul published 
Tables founded on the elements given by Lindenau, Mon. Corr . 
vol. 10. Elaborate discussions of the transits of 1761 and 1769 
have since been published by Encke, in separate works. 
In the Milan Epliemeris 1801, and the Mon. Corr. vol. 2, are 
discussions of the elements and perturbations of Mars by Oriani 
and Wurm. In 1811, Lindenau published Tables of Mars. The 
Greenwich observations were used as far as possible ; but as 
the observation of Mars was finally abandoned there, he had re¬ 
course to continental observations. The variations of the ele¬ 
ments agree nearly with Laplace’s. In the Ast. Nachr. No. 191, 
are physical observations of Mars at the opposition of 1830, 
by Beer and Madler; they have fixed his time of rotation at 
24 h 39 m . Many physical observations of Mercury, Venus, and 
Mars, by Schroter, at the beginning of the century, are to be 
found in his works and in the Berliner Jahrbuch. In the PhiL 
Trans. 1831, are remarks on Mars by Sir James South ; two 
observations on stars seen very near the planet, lead him to 
doubt the existence of any extensive atmosphere. In No. 
29 Ast. Nachr. are observations by Rumker at Paramatta, for 
the parallax of Mars. Tables of Jupiter and Saturn, founded 
