436 E. 8. Holden—Proper Motion of the Trifid Nebula M. 20. 
Observations of MASON and SMITH. 
August 1: “The double star is certainly not as figured in 
Phil. Trans; 1833, but rather adhering to the |eastern| of the vies 
i ns.’ 
839. yey 9..: “The triple star is certainly not central, ore 
involved * ” Trans. Amer. Phil. Soc y, vol. vii, pp. 175- 
N. 
Fig. 3. HerscHen, 1834-8. 
Observations of Sir Joun Hersener at the Cape of Good Hope. 
1835. August...: “I have been rather unfortunate in my fig- 
r Y “ 
ures of this “nebula. That given in my Northern Catalogue (our 
figure 1) is not to be taken as more than an attempt, and that a 
most rude and imperfect one, to show the situation of the fine 
triple star in its center with respect to the nearer portions of the 
three principal surrounding nebulous masses. 
oe then speaks of the drawing of Mason (our figure 2) 
as follow 
