26o 



THE POPULAR SCIENCE MONTHLY. 



on the whole, we shall find that the number and faintness of the small 

 stars, seen by any astronomer in any one limited region, are a very 

 fan- test of his own assiduity, and of the excellence of his telescope. 



It will be seen that Le Gen til has made of the star (9 Orionis 

 four stars, adding one to the number seen by Huyghens. These four 

 are the celebrated trapezium of Orion, and they constitute one of the 

 most remarkable multiple stars of the wliole heavens. 



Nebula Orionis. (Le Gentil, 1758.) 



Messier, who examined the nebula carefully, in 1771, gives these 

 four stars, and a very good drawing of the nebula, in " Histoire de 

 1' Academic," 17 VI. This work was extremely creditable, considering 

 his instrumental means, and the comparatively short time spent 

 upon it. 



This trapezium was destined to become famous, for, in 1826, the 

 elder Struve found, close to one of the large stars of the trapezium, a 

 small companion— the " fifth star." This was for a long time consid- 

 ered as a delicate test for an instrument; but, in December, 1832, 

 Herschel found yet another small star— the " sixth star." The tra- 

 pezium now was seen (with suitable means) as in Fig. 3. 



Let us follow the history of the whole nebula for a time, and we 

 shall see what additions have been made to our knowledge of the 

 space near this remarkable group. 



It may be here remarked that the grouping of these six stars is in 

 all probability not accidental, but that they are physically connected : 

 Struve has shown that the chances are 9,000 to one against anv two 



