68 
SCIENTIFIC SUMMARY. 
ASTEONOMY. 
The Secular Acceleration in the Mean Motion of the Moon. — In tlie 
Astronomical Summary of the last number of this Revieio, reference was made 
to a paper by Sir G. Airy on this subject, in which he arrived at results con- 
tradictory to those which had been admitted to be correct by all the great 
mathematicians of the day. At the same time it was pointed out that the 
result obtained by the Astronomer Koyal was unquestionably erroneous, his 
investigations being vitiated by fundamental errors. The supplementary 
number of the Monthly Notices of the Royal Astronomical Society contains 
a further paper by Sir G. Airy, in which, by rectifying most of these errors, 
he arrives at the same result as that found by Prof. Adams, and which has 
been now admitted to be correct for nearly twenty years. Curiously enough, 
Sir G. Airy, in his last paper, does not acknowledge his error, except 
implicitly by giving results diametrically opposed to those of the previous 
paper. 
Nautical Almanac for 1884. — This volume has been just published. Like 
the preceding volume, the places of the Moon have been derived from 
Hansen’s Table with the addition of the empirical corrections deduced by 
Prof. Newcomb, and published in 1878. There may be some doubt as to 
the advisability of introducing these empirical corrections, for they have 
already commenced to deviate from observation. 
Jupiter. — During the autumn the planet Jupiter has been giving evidence 
of considerable activity, and a large number of interesting observations 
have been made.* The famous red spot has faded in colour, and is no 
longer so vivid as during last year, though it is practically as large and as 
conspicuous. Quite lately, however, it has shown traces of a woolly texture, 
not improbably the incipient signs of its gradual disappearance. Prof. Julius 
F. Schmidt, of Athens, has carefully discussed the observations of the time of 
transit of this spot across the apparent central meridian of the planet, with 
the view of determining the time of rotation. From the observations made 
during 1870, he obtains the value — 
9 h 55 m 34 8 -42 
for the time of rotation, and from the observations made during 1880 he 
finds the value — 
9 h 55 m 34 8, 43 
* See also an article by Mr. W. F. Denning in the present number. 
