REPORT ON ASTRONOMY. 
151 
denau’s value of nutation, (and therefore smaller than any other 
received mass,) he put in a tabular form the corrections to be 
applied to Carlini’s Tables. (Some numerical results of these 
had been published about half a year before.) These have 
been adopted in the Berlin and other ephemerides ; in that of 
Milan they are adopted, excepting the mass of the Moon, for 
which mine is substituted. Nothing was added by Bessel to 
the theory. In Nos. 172, 179, and 217 of the Ast. Nachr. the 
corrected Tables are compared with observations; in the last 
place Bessel conceives that something is still wanting to the 
theory. I have also compared more than 200 Cambridge ob¬ 
servations with the Berlin Ephemeris, and I think that this 
suspicion is well founded. It is understood that Bessel is em¬ 
ployed on more complete solar Tables. 
The change in the obliquity of the ecliptic, and the length 
of the solar year, are obtained from discussions of solstices and 
of solar Tables. The former of these are scattered about very 
much ; but a most able discussion of all the valuable conclusions, 
with reference to both these objects, is contained in Cacciatore’s 
observations. The annual diminution of obliquity is now almost 
fixed at 0 ,/ *4<5. The mass of Venus given by this number 
agrees nearly enough with that obtained from the inequalities 
of the Sun’s longitude. 
Little has been done in observing the solar spots, &c. Some 
observations are contained in the Conn, des Temps 1805, and 
the Berliner Jahrbuch 1828: one of the best papers is perhaps 
that by Mosotti in the Milan Epliemeris 1821. In 1827, the 
Frankfort Society published some figures &c. of spots observed 
by Sommerring. 
During this century, several astronomers, (in the German 
periodicals,) from comparisons of the duration of the sun’s transit 
with the difference of zenith distance of the upper and lower 
limbs, had been led to the conclusion that the Sun’s figure is 
that of a prolate spheroid. As two observers seldom give the 
same duration to the Sun’s passage, this notion seemed in itself 
to deserve little attention. In the Milan Ephemeris , however, 
for 1821, is a series of observations with a divided object-glass 
by M. Mosotti, which seem to establish the sphericity of the Sun. 
In 1806, the French Board of Longitude published Burg’s 
Lunar Tables. In these the arguments of the inequalities 
were taken from Laplace’s theory, and the coefficients from the 
Greenwich observations. In one instance only were so few as 
668 equations of condition used to determine the value of a 
coefficient. They were compared with observations, and re¬ 
ceived the prize of the French Institute. In these, for the first 
time, Laplace’s (or rather D’Alembert’s) equation of long period 
