Notices respecting New Books. 299 



sufficiently extended to allow any detailed deductions to be 

 made ; and the effects of annealing will form one of the chief 

 parts of subsequent investigations. 



From Table II. it will be seen that the greater part of the 

 magnetism has been shaken out by the first fall ; this holds 

 throughout, except in the case of magnet No. 10. I am in- 

 clined to think that this is due to an error in placing the magnet 

 in position ; in this case also the percentage loss was calcu- 

 lated from a diminished deflection of one scale-division only. 



XXXIY. Notices respecting New Books. 



Annual Companion to the 'Observatory,' a Monthly Revieiv of Astro- 

 nomy. Edited by E. W. Maunder, F.R.A.S., A. M. "W. Down- 

 ing, M.A., F.B.A.S., and T. Lewis, F.R.A.S. London : Taylor 

 and Francis. 1887. 



OUR contemporary ' The Observatory,' which was started, some 

 ten years ago, by the present Astronomer Boyal, to supply a 

 want then very greatly felt, used to supply its readers every month 

 with an Astronomical Ephemeris. 



This Ephemeris was useless to its many subscribers in the 

 Colonies and other distant parts of the world. Partly for this 

 reason, and partly in order to extend the scope of the work, the 

 Editors resolved to prepare all the information desirable more than 

 a year in advance, and this they have carried out in the ' Companion 

 to the Observatory.' The idea suggested itself to them towards 

 the end of 1885, and, acting upon it at once, the ' Companion ' for 

 1886 appeared in time. The present number, for 1887, is so com- 

 plete, so well arranged, and so admirably suited to the wants of the 

 practical Astronomer, that it is difficult to suggest any improve- 

 ment to it. 



It begins with a short Introduction, stating the sources whence 

 the Ephemerides have been derived, frequently such as are not 

 generally available to the English reader ; such as the Annuaire du 

 Bureau des Longitudes, the 'American Nautical Almanac,' the 

 Astronomische Naehriehten, &c. 



The first part of the work is a Calendar, giving for every day the 

 times of rising, culminating, and setting of the Sun and Moon ; 

 the Equation of Time, in the form of Mean Time at Apparent 

 Noon ; the Sidereal Time at Mean Noon ; the fraction of the year 

 elapsed since January 1 ; the quarterings of the Moon ; and the 

 principal showers of Shooting-stars. 



Next follow the places, diameters, times of rising, culminating, 

 and setting of the major Planets ; particulars of Eclipses and of 

 Occultations of fixed Stars by the Moon, visible at Greenwich, in 

 which a better mode of reckoning the angles is introduced. The 

 phenomena of Jupiter's Satellites are given in extenso from the 



