200 ASTRONOMY. 



The following stars (among others) are too small in the Paris chart: 



E. A. 10^ 16°^ 0« 



8 11 



10 22 



10 12 



18 25 



18 29 



10 18 39 



8 + 120 lO'.O 



12 42 .5 



12 42 .0 



12 23 .5 



12 56 .5 



12 51 .5 



+ 12 50 .2 



The following stars (among many others) are too large in the Paris 

 chart : 



E. A. lO'^ lO'" 13«; +130 27'.5. Paris G°', reallv O-" 



10 2 30 ; + 11 24 .0. Paris 8™, really 9-10 ™, 

 and many others. 



The configurations of the Paris chart are often quite wrong ; perhaps 

 the worst cases are at 



E. A. 10^^ 4'^ 30»-60«; (5+10O 15'-25'. 

 10 14 ; +11 30-45. 



In every one of these cases the Hamilton College chart was correct; 

 and after a careful examination of nearly every star on this latter chart 

 I found only one case in which the chart seemed to me in the least 

 erroneous. One faint star seemed to me about 1™ too bright. 



This chart was not only an accurate map of the stars, it was also a 

 picture of them, and a configuration of stars in the sky would at oncej 

 catch the eye on the maj), and vice versa. It need hardly be said tha 

 this is not true of any other series of charts existing, not even of the maps 

 of Argelander's Burclimiisterung. 



The exj^lanation is not far to seek, and lies in the perpetual revision to 

 which the Hamilton College charts have been subjected. It is only 

 fair to say that this excellence would appear somewhat less striking if 

 the charts were used in connection with a telescope different from that 

 by means of which they were constructed. They would, in any case, 

 remain the most admirable series now existing ; and they would be of 

 great value and would save much time and labor. For instance, in 

 the observation of asteroids with the transit- circle of the Naval Observa- 

 tory, much time is now wasted in finding the asteroid with the 9-inch 

 equatorial. This amounts, in some cases, almost to a new discovery. If 

 these maps were available at the Naval Observatory^, this labor would be 

 materially lightened. Astronomers are to be congratulated that Dr. 

 Peters has decided to publish these beautiful charts. 



Schoenfeld's Durchmustenmg of all stars to the tenth magnitude, in- 

 clusive, from —2° to —23° of declination, is very nearly finished ; 

 350,000 observations have been made, and the map of Hour XIII has 

 been finished. It contains 4,233 stars. It is probable that the whole 

 work will be finished by 1883. 



For the convenience of those who are using star charts, the following 



i 

 1 



