420 Analysts of Books, [J uly, 
adjust the level, and point the telescope of the instrument as 
nearly to the true meridian as can be guessed. The time of 
passage of any two stars across the centre wire is then noted, 
selecting from the Tables in the book two which differ decidedly 
in their altitude. If both pass corredtly to the time given in the 
Tables, the instrument is rightly fixed. If the lower star passes 
too soon, the transit instrument has been pointed to the east of 
the true meridian. If, on the contrary, the lower star passes too 
late, the conclusion is that the instrument is turned to the 
westward. 
When once the adjustment is completed the correct local time 
may easily be found by noting the stars which pass the meridian 
and comparing their transit with the time given in the Tables. 
A correction is then made to find Greenwich time, accordingly 
as the place of observation lies to the east or west of Greenwich. 
The difference of longitude is converted into time at the rate of 
4 minutes per degree and 4 seconds per minute of longitude. 
If the place of observation is westward of Greenwich this differ- 
ence is added to the time given in the tables, but if it is situate 
eastwards it is subtracted. 
The Tables show the transits of the sun, and of five of the 
principal stars for every day of the current year, and also the 
transits, altitude, and declination of a number of additional 
stars. 
The second part of the book shows, for each day of the year, 
the rising and setting of the sun ; the rising, transit, and setting 
of the moon ; the sidereal time at mean noon ; and the mean 
temperature at 9 a.m. The opposite page shows the rise, transit, 
and setting of Mercury, Venus, Mars, Jupiter, and Saturn for six 
days in each month, and their relative positions to the moon and 
to different constellations. 
The work before us will aid in popularising astronomical ob- 
servation. 
From the Molecular World * Heidelberg : Carl Winter. 
This remarkable book appears without the name of the author, 
though to anyone acquainted with the modern chemical literature 
of Germany the secret of its origin will be exceedingly open. 
The author represents himself as on a visit to Naples, and as 
viewing with no small interest the Aquarium, which by the way 
— unlike certain establishments of the same name nearer home — 
is a genuine scientific institution, and not a place of assembly 
* Aus der Molecular-Welt, 
