i>0 



Astronomical Science ; 



[July 



Last, though not least, Astronomers, in various parts of Europe, 

 have lately been simultaneously employed in laying down the approxi- 

 mate place upon a chart, of all the stars in the heavens, within cer- 

 tain limits of declination, down to the I2th magnitude ; each Astrono- 

 mer undertaking one hour of right ascension, or one twenty-fourth 

 part of the work. The purpose for which these observations were 

 undertaken, was to determine if any planets yet remained undiscover- 

 ed in our system. Up to the present time none have been discovered, 

 but we may hope, in a few years, when this examination shall have 

 been repeated, that we shall be able to pronounce, with certainty, the 

 number of planets which compose the solar system ; for, it is almost 

 needless 10 remark, many planets may possibly exist, of small 

 dimensions, of which we now have no knowledge. 



In addition to the above, there are several points to which attention, 

 at a well appointed observatory, might advantageously be directed, 

 which from their importance may properly be called the desiderata in 

 astronomy. 



At present Astronomers consider the following points among the 

 desiderata : 



1st. A large catalogue of the right ascension and declinations of the 

 principal fixed stars. The catalogue should contain at least 3,000 stars, 

 judiciously selected, and should attain to an accuracy of half a tenth of 

 a second of time, for the right ascension, and be correct to one second 

 of space, for the declination. 



2d. A set of accurate observations, at various points upon the sur- 

 face of the earth, of the altitude of the fixed stars, from fifteen degrees of 

 altitude down to the horizon; the observations should comprehend all 

 possible varieties of temperature and pressure, and the most scrupu- 

 lous care be paid to the states of the barometer, thermometer and 

 hygrometer. 



3rd. Accurate observations of the planet Mars, and of stars near to 

 his path at the time of the opposition, for the purpose of finding his 

 parallax. 



4th. Observations for a more accurate determination, than we at 

 present possess, of the amount of the nutation of the earth's axis, 

 caused by the action of the moon. 



5th. Observations directed to the determination of the density of the 

 planet Saturn. At present its density is assumed to be one eighth of the 

 density of the earth; but this requires verification. 



6th. Observations tending to point out the nature of the discrepancies, 

 which at present affect the tables of the Sun, Moon and planets, gene- 

 rally. ■; 



7th. Observations tending to establish, or refute, the at present re- 

 ceived opinion, « that the solar system is replete with an ether." The 



