E. S. Holden—Proper Motion of the Trifid Nebula M.20. 449 
FY, thee line 10-1 is involved in nebulosity preceding 1 by 
about 167°6. 
Vv. The line 35-3 is nearly tangent to the preceding edge of the 
nebula 
Lasseli’s second figure. 
This figure is the result of repeated observations and is to 
be considered as more trustworthy than the former. 
I. Stars 1, 2, 19 are immersed in A. 
IL. The line of stars 12-13 prolonged passes through the nebu- 
losity A preceding 1, and is involved in the nebula A for about 
25” of its length. 
IL. The line 14-20 is involved in A for about 17”, It is to be 
noted here that all of A which precedes the line 1, 2, 19 is in this 
rawing nappueoee fainter than that just on the border of 
which 1, , 19 are situate 
This is “fot so given in the earlier figure, but probably this 
second figure represents more exactly the careful observations 
of Lassell himself. Returning to the second figure we find : 
IV. hoo line 10-1 is inv olved in nebulosity preceding 1 by 
about 16 
. The “line 35-3 is approximately tangent to the preceding 
shore o 
From the Hareecd College observations by Professor Langley 
and from sketches accompanying them the following conclusions 
may bedrawn. As remarked by Prof. Langley these tain 
are not of ae sre = as the micrometric observa 
I. Stars not immersed in A, but wa in “the ‘duck 
channel waick, jotta is filled with faint nebulosi 
he line 12-13 prolonged i is not involved in he nebulosity A, 
IIL. Stars 14-20 not laid down. 
IV. Line 1-10 not sips preceding a: 
V. 35 not laid dow 
In the drawing ads by M. Trouvelot at Harvard College 
Observatory*— 
L Stars 1, 2, 19 are immersed in 4. 
IL The line the does not intersect A, but passes west of it 
by many secon 
UL. lags line 14-20 is not csic eras in A at all. 
IV. The 1-10 preceding 1 is involved in A. 
Vi The. star 35 is not laid 
- From the Washington hediats it appears that— 
I, 1, 2, 19 are immersed in 
IL The line 12-13 pechongel passes through A, Half way 
from this line to the line 1, 2, 19 the nebulosity becomes brighter, 
* Annals Harvard College Observatory, vol. viii, plate 32. This — is not 
copied, as it is but lately published and is in the hands of cpap 
Am. Jour. Sot SS Vou. XIV, No. 84.—DeEc. 
