E. S. Holden—Proper Motion of the Trifid Nebula M. 20. 489 
_ Observations at the Harvard College Observatory. 
1866. July 31. 
Prof. Sie discovered the 4th star of Sh. 379 Sa ra which he 
estimated 13 mag., and whi ae ue described as “blue.” inde- 
pendently seen ea Prof. Winlock, Measures of codr Saas made, 
— August 
[The following ree are copied verbatim from the original 
observing books, orca that. I have replaced the letters which are 
assigned to the stars by Prof. Langley, by Lassell’s numbers, for - 
the fee of antfoemit ty. The peptone’ in square brackets are 
m 
1866. August 11. 
Méxsulds of coérdinates of stars [omitted]. ‘Observed just 
south of 1, 10, 7, a faint, straight, narrow channel nearly filled up 
with nebulous matter. Was less confident to-night that the nebula 
surrounded the quadruple star, which seemed to be in the channel 
with blackness on each side, less in the preceding than in the fol- 
lowing side. 
1866. August 13 
Fifth component (E) of Sh. 379 discovered by. Prof. Langley. 
1866. September 10 
The entire region south of 1 [C] is judged, as before, to be the 
brightest part of the nebula, Ge nearly so, Cannot fe el sure that 
there is any nebulosity about 1. The channel [south of] 1, 10, 7, 
is rather suspected than seen 
The drawing of M. Trouvelot was made with the aid of the 
Harvard College refractor (of 15 inches aperture) in 1874, and is 
published in the Annals of the Harvard College Observatory, 
as 
proper p place. The following oe ae made by me with the 
26-inch refractor of the U. 8S. Nay al Observatory “pbdalate 
the materials at our — 
in detail.* 
I give the Washington pisces almost literally from the 
* Printed b fee ssion of pontine John Rodgers, U. 8. N., Superinten- 
dent of the U. 8. Naval Observato 
