366 



ANNUAL OF SCIENTIFIC DISCOVERY. 



Other astronomers have before conceived that they have detected a 

 second satellite of Nepture, but have been deceived, and no other 

 notice of the above having been published, it is probable that Mr. Las- 

 sell was mistaken. Editors. 



OBSERVATIONS OF NEPTUNE BEFORE ITS DISCOVERY AS A 



PLANET. 



DR. PETERSEN writes to the Astronomical Journal, No. 6, that Dr. 

 Lament has twice recorded the planet Neptune as a fixed star, in his 

 zones. The first time was October 25, 1845, when he estimated it as 

 of the ninth magnitude ; he observed its transit over the middle thread 

 at 21 h> 42 m> 43 !- .l ; the second time was September 7, 1846, when 

 it crossed the second thread at 21 h< 54 m> 24 S \9, and was entered as of 

 the eighth magnitude. 



SPOTS IN JUPITER. 



PROF. SCHUMACHER, in a letter in the Astronomical Journal, No. 10, 

 states that Mr. Lassell, on March 27, with his twenty-foot refractor 

 (twenty-four inches' aperture and a magnifying power of 430), ob- 

 served four or five remarkable white spots in the belt directly above 

 the middle belt on Jupiter's disk. "The principal spot is exactly 

 half way over at llh. (Greenwich M. T.) They are all perfectly 

 round, distinct, and bright. The largest is as plain as I have seen 

 with the nine- foot telescope the disk of a satellite just entered within 

 the limb, and as well defined. They keep their relative positions as 

 they are carried along by Jupiter's rotation ; and there are no other 

 similar spots anywhere on the disk." 



The announcement to the Royal Astronomical Society of London 

 makes the number of spots six. 



COMETS OF 1850. 



DURING the year 1850, several comets have been discovered. The 

 first one, known as Petersen's comet, was first discovered by Dr. 

 Petersen, at the Altona Observatory, on May 1. After the first an- 

 nouncement in the Astronomische Nachrichten, observations were mul- 

 tiplied with great rapidity, both before and after it became visible to 

 the naked eye. From its first appearance, as seen at Cambridge 

 through the great refractor, it presented a bright stellar point in its 

 centre. On July 10, a tail of 4 or 5 was visible in the comet-seeker, 

 with an evident curvature, the convexity presented to the zenith. 

 This comet was discovered near the north pole, and disappeared near 

 the south pole. Its minimum distance from the earth was about 

 thirty-eight millions of miles. The first European observations were 

 represented by elements which made the probability of a collision with 

 our planet a matter of serious apprehension, but subsequent observa- 

 tions disclosed their error. 



Mr. George P. Bond, of the Cambridge Observatory, discovered a 



