E. S. Holden— Proper Metin of the Trifid Nebula M.20. 451 
Ill. The line age wi dah pc ~ IIerschel, cannot be traced ; 
Mason—cannot be traced ; Lassell (1)—is i involved in A; Las- 
sell (2)-—is eee in A; apieye ts not involved in 4; Trou: 
velot—is not involved's in A; Holden—is involved in 
e line 10-1; the evidence under this head corroborates 
that ides I, except in the case of Harvard College, 1 
. The line 35-3: He rschel, star 35 not laid lowh: Mason, 
star 35 not lai d down; Lassell (1), stars Bees: about tangent to 
35-3 intersects the fainter nebulosity A, te is about tangent to 
the brighter part of A near the triple sta 
. In these points I-V, it appears that there are few discrepan- 
cies A the difference i in telescopes will not explain, and infer- 
ence % is con 
General notes on the brighter portions of the Nebula. 
The brighter portions only are considered, in order to avoid 
as much as poss gt => discrepancies arising from differences 
of instrumental 
In this sxnnsietrian again it will be convenient to derive a 
series of api ges from each drawing in succession, which 
can afterwards be compared. 
The following anal yats may be made of the figure of Her- 
schel (1837). 
A. The brightest nebulosity i is that following 1-2-19, that called 
B, and that called C. The bounding line of C is stra angely different 
in Herschel and Mason’s figures, as remarked b on former. Mason 
refers in his notes to the outline as given b hel. 
B To understand the distribution of the aiten nebulosity, 
C. { a reference must be made to ox drawing. 
D. Star 12 is on the very edge of the following side of B. 
might even be supposed to have been intended to be laid down in 
the channel y. 13 is immersed, but not muc 
E. Star 11 is immersed in 
G. Star 6 in immersed in A. 
H. Star 5 is on the preceding side of A 
J. The —— defined by stars 40, ‘44, 21 [these stars not 
Herschel makes this inference somewhat 
7 se ee 
the aiesh ies of C near where star 21 would be, is 1 
