376 Astronomy and Photography at Rome. 



the specula employed ; the effect is wonderful, and is heightened 

 by being thrown on a beautiful deep azure ground. A globe must 

 have upwards of fifty yards diameter, equal to the width of our 

 Exchange area, to have room for so large a representation of the 

 nebula in question. The same process has been applied, and 

 with equal success, to the nebula in the Girdle of Andromeda. 

 Altogether, it is a discovery of the highest importance to astro- 

 nomical research. 



The account of the labors of the Roman and Neapolitan astron- 

 omers upon these different objects is highly interesting, as an ex- 

 ample of successful care and diligence. Besides a mass of lunar 

 and planetary observations made with micrometrical accuracy, 

 and those on the falling stars, for the purpose of ascertaining the 

 difference of the longitude of their two observatories, the Signor 

 De Vico has drawn up a table, by micrometrical measurement, 

 of the apparent right ascension and declination of twenty six 

 stars encircling the double star Theta, in the nebula of the 

 Sword of Orion, and contained in a space hardly exceeding 

 that of half the apparent disc of the sun. This table, com- 

 bined with the corresponding photographic portrait, will detect 

 any changes that time may effect in that which has been just- 

 ly styled the " transcendently beautiful Queen of the Nebulas." 

 By using a magnifying power of 824 on some nights of ex- 

 treme purity of atmosphere, Signor De Vico has also succeeded 

 in resolving the nucleus of the nebula of Andromeda into a num- 

 ber of luminous points equal in splendor, and very close to one 

 another. He promises to give hereafter the positions of some of 

 the principal of the great number of exceedingly minute stars 

 scattered over this nebula, which since the year 1612, when it 

 was first observed by Simon Marius, has engaged so much of the 

 attention of astronomers. Neither Marius, nor Messier, nor Le 

 Gentil could discern any star in it ; and even Sir John F. W. 

 Herschel could not recognize " the slightest appearance to give 

 ground for a suspicion of its consisting of stars." But a happily 

 constructed telescope, with a purer sky, has led the Roman astron- 

 omers to a different result. Here again the Daguerreotype comes 

 with powerful aid to assist their investigations, and numerous 

 minute stars are seen distinctly sprinkled over the beautiful pho- 

 tographic portrait. 



