THE NEBULA ABOUT e ORIONIS. 95 



minates abruptly and roughly at No. 50, and the nebula immedi- 

 ately assumes a totally different and a milder character. 



Again, on the preceding side of the Messierian branch, near No. 

 75 of my catalogue, I do not find so bold an indenture as he has 

 given. It is in this neighbourhood only that I have found any 

 difficulty in identifying his stars. I presume that I have here two 

 new stars, but neither No. 75, nor the two next south of it, 

 agrees in position with any of the stars in his catalogue. 



The preceding side of the Huygenian region in his figure has 

 the light gradually softened away into the " Regio Gentiliana." 

 I here see a strong irregular outline, extending from the " Sinus 

 Gentilii" to a little beyond No. 10. 



The positions of the stars marked with an asterisk, in the an- 

 nexed catalogue, were determined by alignment only, from stars 

 in their neighbourhood which had been subjected to micrometrical 

 measurement. This approximate method was considered suffi- 

 ciently accurate in this case, as the stars in question were, from 

 their situation, of minor importance in regard to the principal ob- 

 ject which I had in view, namely, a true delineation of the nebula. 

 In this catalogue the stars are numbered in the order of their 

 right ascensions, and are all referred, in seconds and decimals of 

 seconds, of arc, to 6' (No. 22) of the Trapezium. 



In the column headed x, — signifies that the star precedes, and 

 + that it follows d\ by so many seconds, measured in the direction 

 of AR. 



In the column headed y, + signifies that the star has greater, 

 and — that it has less, north polar distance than dK 



