464 Scientific Proceedings, Royal Dublin Society. 
advantage above all others hitherto published, that it was to be 
the work of a single individual, observing all the stars in both 
hemispheres visible to the naked eye within a short space of 
time. He accordingly commenced working on January 28, 1875, 
and the work was finished on February 28, 1876. He had first 
prepared maps, on which all the stars were plotted down without 
regard to magnitude ; then every region was gone over two or 
‘three times, and the magnitudes carefully estimated, the six usual 
classes being used, but each class only divided into two halves. 
The atlas thus formed consists of five plates, on which the stars, 
their letters, the names and limits of the constellations (but not 
their figures), and the milky way are depicted. The latter has 
been attended to with great care, the deeper or paler hue of the 
light-ereen colour representing greater or lesser brightness. The 
equatorial zone between +45° is drawn on a cylindrical projec- 
tion, the circles of R.A. and Decl. being equidistant parallel lines, 
and the two polar calots on a polar projection, the parallels being 
equidistant circles. The catalogue of stars for 1880 is divided 
into four sections, separated by the equator and the parallels of 
45°, It contains 5719 stars. M. Houzeau has examined the dis- 
tribution of the stars in four ways: 1, with respect to the solar 
equator; 2, with respect to the direction of the sun’s proper 
motion ; 8, perpendicular to this direction; 4, with respect to 
the milky way. No law whatever was found in the first three 
ways, while the fourth mode of proceeding confirmed W. Struve’s 
conclusion that the density of stellar layers parallel to the plane 
of the milky way decreases very regularly and gradually towards 
the poles of the latter. 
Another Uranometry which has been looked forward to for a 
long time, Gould’s “ Uranometria Argentina,” has been published, 
and copies arrived in Europe about the end of the year. Not 
yet having seen this most important work, we borrow the 
following account of it from the Buenos Ayres “Standard,” 
quoted in The Observatory for December. This Uranometry was 
intended to embrace all stars within 100° of the South Pole 
down to the seventh magnitude, the limit of visibility in the 
clear sky of Cordoba. Four assistants were engaged on the 
work since 1870, and each region was independently mapped 
down by at least two of them, and the magnitude of each star 
