ACCOUNT 



RECENT RESEARCHES RELATIVE TO THE NEBULJl. 



BY PROFESSOR GAUTIER 



Translated for the Smitlisoniau Institution from the Archives des Sciences Physiques el Natu- 



relies, Geneva, 1862. 



There is no part of the vast field of the astronomy of observation which is 

 not at present the object of persevering explorations. I propose on this occa- 

 sion to give a cursory view of those which relate to a widely extended and 

 highly curious class of celestial objects, which was first made a subject of 

 special study by the distinguished astrononiers Herschel and Messier, and 

 since by Lord Ross, by Fathers De Vico and Secchi, and by MM. Lamont, 

 Lassell, and Bond ; a subject which presents peculiar difiiculties, and respecting 

 which there remains much to be cleared up. I allude to the nebulae, those 

 small whitish patches, of feeble light, which the telescope reveals to us in great 

 numbers in the heavens, and which powerful instruments enable us, for the 

 most part, to recognize as assemblages of stars, situated at enormous distances 

 from the earth. 



In this rapid review I shall follow, in general, the order of dates, and I shall 

 commence by saying a few words of a catalogue of the positions in the heavena 

 of fit\y-three nebulae, the result of observations made at the observatory of 

 Paris by M. Langier, principally in 1848 and 1849, and by him presented to 

 the Academy of Sciences of Paris at its sitting of December 12, 1853. This 

 catalogue, published in the Compte Rendu of that sittiug, gives with the precision 

 of seconds of a degree the right ascensions and mean declinations of the centre 

 or most brilliant point of those nebulee to January 1, 1850, as well as the 

 differences between these positions and those resulting from the catalogues of 

 Herschel and Messier. It is a first attempt at precise determinations of the 

 position of a certain number of nebulae, undertaken with a view of serving to 

 decide, in the sequel, the question whether these bodies are really situated 

 beyond the fixed stars which are visible to us. 



RESEARCHES RELATIVE TO THE NEBULA OF ORION. 



M. Liapounoff, director of the observatory of Kazan, in the beginning of 1856 

 presented to the Academy of Sciences of Petersburg!!, through the medium of 

 M. W. Struve, a memoir on the great nebula of Orion, being the result of 

 observations made for four years with an equatorial telescope of the power 

 of that of Dorpat and a meridian circle of Repsold.* He has applied himself 



* I know this memoir only from a very succinct mention of it at the entl of the number of 

 the Monthly Notices of the Astronomical Society of Loudon for March 14, 18.')G, vol. xvi, 

 p. 139. As I shall frequently have to cite this compilation, as well as that published at 

 Altona by Dr. Peters under the title of Astronumische Nachrichten, 1 shall designate them 

 respectively by then initial letters, M. N. and A. N. 



