E. 8. Holden— Proper Motion of the Trifid Nebula M.20. 453 
From the MS. observations and ae of Professor Lang- 
ley the following conclusions may be draw 
A. “The brightest nebulosity is about 1” ie ~ “ The 
region south of 1 is judged to be the brightest” (Sept. 10). 
C. See the observations in detail. 
D. Stars 12, 13 are immersed. 
E. Star 11 is, if wupthinas muses of A. 
F. Star 26 not laid down. 
G, Star 6 is, if anything, outside of A. 
H. Star 5 is near the Niel edge of A, but immersed. 
J. 40, 44, 21 not laid dow 
K. Stars 30 ? 35? are immersed in C south of the channel a. 
L. No measures — on the sketches, but it in general 
agrees with ‘Trouve 
From the drawing of M. Trouvelot, which gives the general 
effect of the nebula to the eye bett ter than any other, we 
deduce what follows: 
A. The brightest part of the nebula is in A south following 
tae ae 8 8 
"B. Next in order of brightness is the nebulosity about star 40. 
C. The northern borders of C are next in order of brightness. 
D. Stars 12 and 13 are immersed in B, 
E. Star 11 follows the extreme edge os me a little (see his out- 
line- go of stars in Annals H. C. Obs., 
F. Star 26 is teitoanly surrounded ee cleats light nebu- 
losity. 
G. Star 6 is within the padersiiing edge of A (outline-map). 
H. Star 5 is within A (outline-map). 
J. triangle 40, 44, 21 contains a considerable amount of 
pretty bright nebulosit 
Star ie is on may northern border of C, Stars 35 and 36 are 
not laid dow 
The resu aa Are, oo is K, for the Washington observa- 
tions are laid down in the detailed transcription of those obser- 
vations (1877, July 30) and need not be repeated here. “As to 
L, we may say that the 46 of the north shore of C, 7* preceding 
lis about —65”. 
We may summarize the foregoing results as follows: First 
as to the distribution of the brightest portions 
In all of the drawings the pace wigs closely pes the triple 
star is of the first order of brightness, while in the Washington 
observations between 1 and 10 a ag Se lead exists. J am 
Fetnces g 1, exists. 
